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freebsd-dev/sys/kern/kern_malloc.c

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/* -> /*- for copyright notices, minor format tweaks as necessary
2005-01-06 23:35:40 +00:00
/*-
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
* Copyright (c) 1987, 1991, 1993
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
* The Regents of the University of California.
struct malloc_type has had a 'magic' field statically initialized to M_MAGIC by MALLOC_DEFINE() for a long time; add assertions that malloc_type's passed to malloc(), free(), etc have that magic set. MFC after: 2 weeks
2009-04-19 12:41:37 +00:00
* Copyright (c) 2005-2009 Robert N. M. Watson
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
* All rights reserved.
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_malloc.c 8.3 (Berkeley) 1/4/94
*/
Expand comments for malloc(9) to better describe the design and statistics / memory types model.
2006-07-23 19:51:39 +00:00
/*
* Kernel malloc(9) implementation -- general purpose kernel memory allocator
* based on memory types. Back end is implemented using the UMA(9) zone
* allocator. A set of fixed-size buckets are used for smaller allocations,
* and a special UMA allocation interface is used for larger allocations.
* Callers declare memory types, and statistics are maintained independently
* for each memory type. Statistics are maintained per-CPU for performance
* reasons. See malloc(9) and comments in malloc.h for a detailed
* description.
*/
Use __FBSDID().
2003-06-11 00:56:59 +00:00
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
Add a "show malloc" command to DDB, which prints out the current stats for available kernel malloc types. Quite useful for post-mortem debugging of memory leaks without a dump device configured on a panicked box. MFC after: 2 weeks
2005-10-20 17:41:47 +00:00
#include "opt_ddb.h"
Try to dynamically size the VM_KMEM_SIZE (but is still able to be overridden in a way identically as before.) I had problems with the system properly handling the number of vnodes when there is alot of system memory, and the default VM_KMEM_SIZE. Two new options "VM_KMEM_SIZE_SCALE" and "VM_KMEM_SIZE_MAX" have been added to support better auto-sizing for systems with greater than 128MB.
1998-02-23 07:41:23 +00:00
#include "opt_vm.h"
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
#include <sys/param.h>
The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch. Reviewed by: Rodney W. Grimes Submitted by: John Dyson and David Greenman
1994-05-25 09:21:21 +00:00
#include <sys/systm.h>
Update for the KDB framework: o Make debugging code conditional upon KDB instead of DDB. o Call kdb_enter() instead of Debugger(). o Call kdb_backtrace() instead of db_print_backtrace() or backtrace(). kern_mutex.c: o Replace checks for db_active with checks for kdb_active and make them unconditional. kern_shutdown.c: o s/DDB_UNATTENDED/KDB_UNATTENDED/g o s/DDB_TRACE/KDB_TRACE/g o Save the TID of the thread doing the kernel dump so the debugger knows which thread to select as the current when debugging the kernel core file. o Clear kdb_active instead of db_active and do so unconditionally. o Remove backtrace() implementation. kern_synch.c: o Call kdb_reenter() instead of db_error().
2004-07-10 21:36:01 +00:00
#include <sys/kdb.h>
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
#include <sys/kernel.h>
Undo part of the tangle of having sys/lock.h and sys/mutex.h included in other "system" header files. Also help the deprecation of lockmgr.h by making it a sub-include of sys/lock.h and removing sys/lockmgr.h form kernel .c files. Sort sys/*.h includes where possible in affected files. OK'ed by: bde (with reservations)
2001-05-01 08:13:21 +00:00
#include <sys/lock.h>
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
#include <sys/malloc.h>
- machine/mutex.h -> sys/mutex.h - Use MUTEX_DECLARE() and MTX_COLD for the malloc_mtx mutex
2000-10-20 07:29:16 +00:00
#include <sys/mutex.h>
Untangled the vm.h include file spaghetti.
1995-12-07 12:48:31 +00:00
#include <sys/vmmeter.h>
Make intr_nesting_level per-process, rather than per-cpu. Setup interrupt threads to run with it always >= 1, so that malloc can detect M_WAITOK from "interrupt" context. This is also necessary in order to context switch from sched_ithd() directly. Reviewed By: peter
2001-01-21 19:25:07 +00:00
#include <sys/proc.h>
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
#include <sys/sbuf.h>
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
#include <sys/sysctl.h>
Introduce malloc_last_fail() which returns the number of seconds since malloc(9) failed last time. This is intended to help code adjust memory usage to the current circumstances. A typical use could be: if (malloc_last_fail() < 60) reduce_cache_by_one();
2002-11-01 18:58:12 +00:00
#include <sys/time.h>
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
#include <sys/vmem.h>
Don't #include <sys/proc.h>, since machine/mutex.h does it now.
2000-09-23 00:01:37 +00:00
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
#include <vm/vm.h>
- Split UMA_ZFLAG_OFFPAGE into UMA_ZFLAG_OFFPAGE and UMA_ZFLAG_HASH. - Remove all instances of the mallochash. - Stash the slab pointer in the vm page's object pointer when allocating from the kmem_obj. - Use the overloaded object pointer to find slabs for malloced memory.
2002-09-18 08:26:30 +00:00
#include <vm/pmap.h>
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
#include <vm/vm_pageout.h>
Untangled the vm.h include file spaghetti.
1995-12-07 12:48:31 +00:00
#include <vm/vm_param.h>
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
#include <vm/vm_kern.h>
Untangled the vm.h include file spaghetti.
1995-12-07 12:48:31 +00:00
#include <vm/vm_extern.h>
Get rid of the ad-hoc memory allocator for vm_map_entries, in lieu of a simple, clean zone type allocator. This new allocator will also be used for machine dependent pmap PV entries.
1997-08-05 00:02:08 +00:00
#include <vm/vm_map.h>
- Split UMA_ZFLAG_OFFPAGE into UMA_ZFLAG_OFFPAGE and UMA_ZFLAG_HASH. - Remove all instances of the mallochash. - Stash the slab pointer in the vm page's object pointer when allocating from the kmem_obj. - Use the overloaded object pointer to find slabs for malloced memory.
2002-09-18 08:26:30 +00:00
#include <vm/vm_page.h>
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
#include <vm/uma.h>
#include <vm/uma_int.h>
Add a new UMA debugging facility. This will overwrite freed memory with 0xdeadc0de and then check for it just before memory is handed off as part of a new request. This will catch any post free/pre alloc modification of memory, as well as introduce errors for anything that tries to dereference it as a pointer. This code takes the form of special init, fini, ctor and dtor routines that are specificly used by malloc. It is in a seperate file because additional debugging aids will want to live here as well.
2002-04-30 07:54:25 +00:00
#include <vm/uma_dbg.h>
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
Bring in MemGuard, a very simple and small replacement allocator designed to help detect tamper-after-free scenarios, a problem more and more common and likely with multithreaded kernels where race conditions are more prevalent. Currently MemGuard can only take over malloc()/realloc()/free() for particular (a) malloc type(s) and the code brought in with this change manually instruments it to take over M_SUBPROC allocations as an example. If you are planning to use it, for now you must: 1) Put "options DEBUG_MEMGUARD" in your kernel config. 2) Edit src/sys/kern/kern_malloc.c manually, look for "XXX CHANGEME" and replace the M_SUBPROC comparison with the appropriate malloc type (this might require additional but small/simple code modification if, say, the malloc type is declared out of scope). 3) Build and install your kernel. Tune vm.memguard_divisor boot-time tunable which is used to scale how much of kmem_map you want to allott for MemGuard's use. The default is 10, so kmem_size/10. ToDo: 1) Bring in a memguard(9) man page. 2) Better instrumentation (e.g., boot-time) of MemGuard taking over malloc types. 3) Teach UMA about MemGuard to allow MemGuard to override zone allocations too. 4) Improve MemGuard if necessary. This work is partly based on some old patches from Ian Dowse.
2005-01-21 18:09:17 +00:00
#ifdef DEBUG_MEMGUARD
#include <vm/memguard.h>
#endif
Add buffer corruption protection (RedZone) for kernel's malloc(9). It detects both: buffer underflows and buffer overflows bugs at runtime (on free(9) and realloc(9)) and prints backtraces from where memory was allocated and from where it was freed. Tested by: kris
2006-01-31 11:09:21 +00:00
#ifdef DEBUG_REDZONE
#include <vm/redzone.h>
#endif
Bring in MemGuard, a very simple and small replacement allocator designed to help detect tamper-after-free scenarios, a problem more and more common and likely with multithreaded kernels where race conditions are more prevalent. Currently MemGuard can only take over malloc()/realloc()/free() for particular (a) malloc type(s) and the code brought in with this change manually instruments it to take over M_SUBPROC allocations as an example. If you are planning to use it, for now you must: 1) Put "options DEBUG_MEMGUARD" in your kernel config. 2) Edit src/sys/kern/kern_malloc.c manually, look for "XXX CHANGEME" and replace the M_SUBPROC comparison with the appropriate malloc type (this might require additional but small/simple code modification if, say, the malloc type is declared out of scope). 3) Build and install your kernel. Tune vm.memguard_divisor boot-time tunable which is used to scale how much of kmem_map you want to allott for MemGuard's use. The default is 10, so kmem_size/10. ToDo: 1) Bring in a memguard(9) man page. 2) Better instrumentation (e.g., boot-time) of MemGuard taking over malloc types. 3) Teach UMA about MemGuard to allow MemGuard to override zone allocations too. 4) Improve MemGuard if necessary. This work is partly based on some old patches from Ian Dowse.
2005-01-21 18:09:17 +00:00
KASSERT that we cannot use M_WAITOK in interrupt context. Reviewed by: bde
1999-09-19 08:40:11 +00:00
#if defined(INVARIANTS) && defined(__i386__)
#include <machine/cpu.h>
#endif
Add a "show malloc" command to DDB, which prints out the current stats for available kernel malloc types. Quite useful for post-mortem debugging of memory leaks without a dump device configured on a panicked box. MFC after: 2 weeks
2005-10-20 17:41:47 +00:00
#include <ddb/ddb.h>
Add support for the DTrace malloc provider which can enable probes on a per-malloc type basis.
2008-05-23 00:43:36 +00:00
#ifdef KDTRACE_HOOKS
#include <sys/dtrace_bsd.h>
dtrace_malloc_probe_func_t dtrace_malloc_probe;
#endif
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
/*
* When realloc() is called, if the new size is sufficiently smaller than
* the old size, realloc() will allocate a new, smaller block to avoid
* wasting memory. 'Sufficiently smaller' is defined as: newsize <=
* oldsize / 2^n, where REALLOC_FRACTION defines the value of 'n'.
*/
#ifndef REALLOC_FRACTION
#define REALLOC_FRACTION 1 /* new block if <= half the size */
#endif
Expand comments for malloc(9) to better describe the design and statistics / memory types model.
2006-07-23 19:51:39 +00:00
/*
* Centrally define some common malloc types.
*/
Before we start to mess with the VFS name-cache clean things up a little bit: Isolate the namecache in its own file, and give it a dedicated malloc type.
1999-10-03 12:18:29 +00:00
MALLOC_DEFINE(M_CACHE, "cache", "Various Dynamically allocated caches");
Get rid of MALLOC_INSTANTIATE and MALLOC_MAKE_TYPE(). Just handle the 3 malloc types declared in <sys/malloc.h> like other global malloc types.
1999-09-11 16:41:39 +00:00
MALLOC_DEFINE(M_DEVBUF, "devbuf", "device driver memory");
MALLOC_DEFINE(M_TEMP, "temp", "misc temporary data buffers");
Have MALLOC_DECLARE() initialize malloc types explicitly, and have them removed at module unload (if in a module of course). However; this introduces a new dependency on <sys/kernel.h> for things that use MALLOC_DECLARE(). Bruce told me it is better to add sys/kernel.h to the handful of files that need it rather than add an extra include to sys/malloc.h for kernel compiles. Updates to follow in subsequent commits.
1998-11-10 08:46:24 +00:00
static struct malloc_type *kmemstatistics;
Introduce a new sysctl, kern.malloc_stats, which exports kernel malloc statistics via a binary structure stream: - Add structure 'malloc_type_stream_header', which defines a stream version, definition of MAXCPUS used in the stream, and a number of malloc_type records in the stream. - Add structure 'malloc_type_header', which defines the name of the malloc type being reported on. - When the sysctl is queried, return a stream header, followed by a series of type descriptions, each consisting of a type header followed by a series of MAXCPUS malloc_type_stats structures holding per-CPU allocation information. Typical values of MAXCPUS will be 1 (UP compiled kernel) and 16 (SMP compiled kernel). This query mechanism allows user space monitoring tools to extract memory allocation statistics in a machine-readable form, and to do so at a per-CPU granularity, allowing monitoring of allocation patterns across CPUs in order to better understand the distribution of work and memory flow over multiple CPUs. While here: - Bump statistics width to uint64_t, and hard code using fixed-width type in order to be more sure about structure layout in the stream. We allocate and free a lot of memory. - Add kmemcount, a counter of the number of registered malloc types, in order to avoid excessive manual counting of types. Export via a new sysctl to allow user-space code to better size buffers. - De-XXX comment on no longer maintaining the high watermark in old sysctl monitoring code. A follow-up commit of libmemstat(3), a library to monitor kernel memory allocation, will occur in the next few days. Likewise, similar changes to UMA.
2005-07-14 11:52:06 +00:00
static int kmemcount;
Fix null-pointer dereference crash when the system is intentionally run out of KVM through a mmap()/fork() bomb that allocates hundreds of thousands of vm_map_entry structures. Add panic to make null-pointer dereference crash a little more verbose. Add a new sysctl, vm.max_proc_mmap, which specifies the maximum number of mmap()'d spaces (discrete vm_map_entry's in the process). The value defaults to around 9000 for a 128MB machine. The test is scaled for the number of processes sharing a vmspace (aka linux threads). Setting the value to 0 disables the feature. PR: kern/16573 Approved by: jkh
2000-02-16 21:11:33 +00:00
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
#define KMEM_ZSHIFT 4
#define KMEM_ZBASE 16
#define KMEM_ZMASK (KMEM_ZBASE - 1)
Re-instate UMA cached backend for 4K - 64K allocations. New consumers like geli(4) uses malloc(9) to allocate temporary buffers that gets free'ed shortly, causing frequent TLB shootdown as observed in hwpmc supported flame graph. Discussed with: jeff, alfred MFC after: 1 week
2014-08-14 05:13:24 +00:00
#define KMEM_ZMAX 65536
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
#define KMEM_ZSIZE (KMEM_ZMAX >> KMEM_ZSHIFT)
Use ISO C99 integer types in sys/kern where possible. There are only about 100 occurences of the BSD-specific u_int*_t datatypes in sys/kern. The ISO C99 integer types are used here more often.
2010-06-21 09:55:56 +00:00
static uint8_t kmemsize[KMEM_ZSIZE + 1];
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
#ifndef MALLOC_DEBUG_MAXZONES
#define MALLOC_DEBUG_MAXZONES 1
#endif
static int numzones = MALLOC_DEBUG_MAXZONES;
Expand comments for malloc(9) to better describe the design and statistics / memory types model.
2006-07-23 19:51:39 +00:00
/*
* Small malloc(9) memory allocations are allocated from a set of UMA buckets
* of various sizes.
*
* XXX: The comment here used to read "These won't be powers of two for
* long." It's possible that a significant amount of wasted memory could be
* recovered by tuning the sizes of these buckets.
*/
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
struct {
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
int kz_size;
char *kz_name;
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
uma_zone_t kz_zone[MALLOC_DEBUG_MAXZONES];
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
} kmemzones[] = {
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
{16, "16", },
{32, "32", },
{64, "64", },
{128, "128", },
{256, "256", },
{512, "512", },
{1024, "1024", },
{2048, "2048", },
{4096, "4096", },
{8192, "8192", },
{16384, "16384", },
{32768, "32768", },
{65536, "65536", },
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
{0, NULL},
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
};
Expand comments for malloc(9) to better describe the design and statistics / memory types model.
2006-07-23 19:51:39 +00:00
/*
* Zone to allocate malloc type descriptions from. For ABI reasons, memory
* types are described by a data structure passed by the declaring code, but
* the malloc(9) implementation has its own data structure describing the
* type and statistics. This permits the malloc(9)-internal data structures
* to be modified without breaking binary-compiled kernel modules that
* declare malloc types.
*/
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
static uma_zone_t mt_zone;
export VM_MIN_KERNEL_ADDRESS and VM_MAX_KERNEL_ADDRESS via sysctl. On several platforms the are determined by too many nested #defines to be easily discernible. This will aid in development of auto-tuning.
2012-11-06 04:10:32 +00:00
Enable the creation of a kmem map larger than 4GB. Submitted by: Tz-Huan Huang Make several variables related to kmem map auto-sizing static. Found by: CScout
2008-07-05 19:34:33 +00:00
u_long vm_kmem_size;
kmem_size* sysctls: hint that these are also tunables MFC after: 1 week
2010-09-30 16:45:27 +00:00
SYSCTL_ULONG(_vm, OID_AUTO, kmem_size, CTLFLAG_RDTUN, &vm_kmem_size, 0,
Rename the kern.vm.kmem.size tunable to the more logical vm.kmem_size. To assure backward compatibility (conditional on !BURN_BRIDGES), look it up by its old name first, and log a warning (but accept the setting) if it was found. If both the old and new name are defined, the new name takes precedence. Also export vm.kmem_size as a read-only sysctl variable; I find it hard to tune a parameter when I don't know its default value, especially when that default value is computed at boot time.
2004-01-27 15:59:38 +00:00
"Size of kernel memory");
malloc/free(9) no longer require Giant. Use the malloc_mtx to protect the mallochash. Mallochash is going to go away as soon as I introduce the kfree/kmalloc api and partially overhaul the malloc wrapper. This can't happen until all users of the malloc api that expect memory to be aligned on the size of the allocation are fixed.
2002-05-02 07:22:19 +00:00
Add a new loader tunable, vm.kmem_zmax which allows a system administrator to limit the maximum allocation size that malloc(9) would consider using the UMA cache allocator as backend. Suggested by: alfred MFC after: 2 weeks
2014-08-14 05:31:39 +00:00
static u_long kmem_zmax = KMEM_ZMAX;
SYSCTL_ULONG(_vm, OID_AUTO, kmem_zmax, CTLFLAG_RDTUN, &kmem_zmax, 0,
"Maximum allocation size that malloc(9) would use UMA as backend");
Enable the creation of a kmem map larger than 4GB. Submitted by: Tz-Huan Huang Make several variables related to kmem map auto-sizing static. Found by: CScout
2008-07-05 19:34:33 +00:00
static u_long vm_kmem_size_min;
kmem_size* sysctls: hint that these are also tunables MFC after: 1 week
2010-09-30 16:45:27 +00:00
SYSCTL_ULONG(_vm, OID_AUTO, kmem_size_min, CTLFLAG_RDTUN, &vm_kmem_size_min, 0,
Add support for specifying a minimal size for vm.kmem_size in the loader via vm.kmem_size_min. Useful when using ZFS to make sure that vm.kmem size will be at least 256mb (for example) without forcing a particular value via vm.kmem_size. Approved by: njl (mentor) Reviewed by: alc
2007-04-21 01:14:48 +00:00
"Minimum size of kernel memory");
Enable the creation of a kmem map larger than 4GB. Submitted by: Tz-Huan Huang Make several variables related to kmem map auto-sizing static. Found by: CScout
2008-07-05 19:34:33 +00:00
static u_long vm_kmem_size_max;
kmem_size* sysctls: hint that these are also tunables MFC after: 1 week
2010-09-30 16:45:27 +00:00
SYSCTL_ULONG(_vm, OID_AUTO, kmem_size_max, CTLFLAG_RDTUN, &vm_kmem_size_max, 0,
Turn VM_KMEM_SIZE_MAX and VM_KMEM_SIZE_SCALE into tunables. MFC after: 3 days
2004-09-29 14:21:40 +00:00
"Maximum size of kernel memory");
Compile fixes: Remove duplicate "debug_ktr.mask" sysctl definition. Remove now unused variable from "kern_ktr.c". This fixes build of "ktr" which was broken by r267961. Let the default value for "vm_kmem_size_scale" be zero. It is setup after that the sysctl has been initialized from "getenv()" in the "kmeminit()" function to equal the "VM_KMEM_SIZE_MAX" value, if zero. On Sparc64 the "VM_KMEM_SIZE_MAX" macro is not a constant. This fixes build of Sparc64 which was broken by r267961. Add a special macro to dynamically create SYSCTL root nodes, because root nodes have a special parent. This fixes build of existing OFED module and CANBUS module for pc98 which was broken by r267961. Add missing "sysctl.h" includes to get the needed sysctl header file declarations. This is needed after r267961. MFC after: 2 weeks
2014-06-28 17:36:18 +00:00
static u_int vm_kmem_size_scale;
kmem_size* sysctls: hint that these are also tunables MFC after: 1 week
2010-09-30 16:45:27 +00:00
SYSCTL_UINT(_vm, OID_AUTO, kmem_size_scale, CTLFLAG_RDTUN, &vm_kmem_size_scale, 0,
Turn VM_KMEM_SIZE_MAX and VM_KMEM_SIZE_SCALE into tunables. MFC after: 3 days
2004-09-29 14:21:40 +00:00
"Scale factor for kernel memory size");
vm.kmem_map_size: a sysctl to query current kmem_map->size Based on a patch from Sandvine Incorporated via emaste. Reviewed by: emaste MFC after: 1 week
2010-10-07 18:11:33 +00:00
static int sysctl_kmem_map_size(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_vm, OID_AUTO, kmem_map_size,
CTLFLAG_RD | CTLTYPE_ULONG | CTLFLAG_MPSAFE, NULL, 0,
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
sysctl_kmem_map_size, "LU", "Current kmem allocation size");
vm.kmem_map_size: a sysctl to query current kmem_map->size Based on a patch from Sandvine Incorporated via emaste. Reviewed by: emaste MFC after: 1 week
2010-10-07 18:11:33 +00:00
add kmem_map_free sysctl: query largest contiguous free range in kmem_map Suggested by: alc Reviewed by: alc MFC after: 1 week
2010-10-09 09:03:17 +00:00
static int sysctl_kmem_map_free(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_vm, OID_AUTO, kmem_map_free,
CTLFLAG_RD | CTLTYPE_ULONG | CTLFLAG_MPSAFE, NULL, 0,
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
sysctl_kmem_map_free, "LU", "Free space in kmem");
add kmem_map_free sysctl: query largest contiguous free range in kmem_map Suggested by: alc Reviewed by: alc MFC after: 1 week
2010-10-09 09:03:17 +00:00
malloc/free(9) no longer require Giant. Use the malloc_mtx to protect the mallochash. Mallochash is going to go away as soon as I introduce the kfree/kmalloc api and partially overhaul the malloc wrapper. This can't happen until all users of the malloc api that expect memory to be aligned on the size of the allocation are fixed.
2002-05-02 07:22:19 +00:00
/*
- Split UMA_ZFLAG_OFFPAGE into UMA_ZFLAG_OFFPAGE and UMA_ZFLAG_HASH. - Remove all instances of the mallochash. - Stash the slab pointer in the vm page's object pointer when allocating from the kmem_obj. - Use the overloaded object pointer to find slabs for malloced memory.
2002-09-18 08:26:30 +00:00
* The malloc_mtx protects the kmemstatistics linked list.
malloc/free(9) no longer require Giant. Use the malloc_mtx to protect the mallochash. Mallochash is going to go away as soon as I introduce the kfree/kmalloc api and partially overhaul the malloc wrapper. This can't happen until all users of the malloc api that expect memory to be aligned on the size of the allocation are fixed.
2002-05-02 07:22:19 +00:00
*/
struct mtx malloc_mtx;
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
Finish adding support code for sysctl kern.mprof. This dumps some malloc information related to bucket size effeciency. Three things are printed on each row: Size is the size the user actually asked for rounded to 16 bytes. Requests is the number of times this size was asked for. Real Size is the size we actually handed out. At the end the total memory used and total waste is displayed. Currently my system displays about 33% wasted memory. The intent of this code is to gather statistics for tuning the malloc bucket sizes. It is not intended to be run with INVARIANTS and it is not entirely mp safe. It can be enabled via 'options MALLOC_PROFILE' which was commited earlier.
2002-04-15 05:24:01 +00:00
#ifdef MALLOC_PROFILE
uint64_t krequests[KMEM_ZSIZE + 1];
static int sysctl_kern_mprof(SYSCTL_HANDLER_ARGS);
#endif
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
Introduce a new sysctl, kern.malloc_stats, which exports kernel malloc statistics via a binary structure stream: - Add structure 'malloc_type_stream_header', which defines a stream version, definition of MAXCPUS used in the stream, and a number of malloc_type records in the stream. - Add structure 'malloc_type_header', which defines the name of the malloc type being reported on. - When the sysctl is queried, return a stream header, followed by a series of type descriptions, each consisting of a type header followed by a series of MAXCPUS malloc_type_stats structures holding per-CPU allocation information. Typical values of MAXCPUS will be 1 (UP compiled kernel) and 16 (SMP compiled kernel). This query mechanism allows user space monitoring tools to extract memory allocation statistics in a machine-readable form, and to do so at a per-CPU granularity, allowing monitoring of allocation patterns across CPUs in order to better understand the distribution of work and memory flow over multiple CPUs. While here: - Bump statistics width to uint64_t, and hard code using fixed-width type in order to be more sure about structure layout in the stream. We allocate and free a lot of memory. - Add kmemcount, a counter of the number of registered malloc types, in order to avoid excessive manual counting of types. Export via a new sysctl to allow user-space code to better size buffers. - De-XXX comment on no longer maintaining the high watermark in old sysctl monitoring code. A follow-up commit of libmemstat(3), a library to monitor kernel memory allocation, will occur in the next few days. Likewise, similar changes to UMA.
2005-07-14 11:52:06 +00:00
static int sysctl_kern_malloc_stats(SYSCTL_HANDLER_ARGS);
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
Expand comments for malloc(9) to better describe the design and statistics / memory types model.
2006-07-23 19:51:39 +00:00
/*
* time_uptime of the last malloc(9) failure (induced or real).
*/
Introduce malloc_last_fail() which returns the number of seconds since malloc(9) failed last time. This is intended to help code adjust memory usage to the current circumstances. A typical use could be: if (malloc_last_fail() < 60) reduce_cache_by_one();
2002-11-01 18:58:12 +00:00
static time_t t_malloc_fail;
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
#if defined(MALLOC_MAKE_FAILURES) || (MALLOC_DEBUG_MAXZONES > 1)
Mark all SYSCTL_NODEs static that have no corresponding SYSCTL_DECLs. The SYSCTL_NODE macro defines a list that stores all child-elements of that node. If there's no SYSCTL_DECL macro anywhere else, there's no reason why it shouldn't be static.
2011-11-07 15:43:11 +00:00
static SYSCTL_NODE(_debug, OID_AUTO, malloc, CTLFLAG_RD, 0,
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
"Kernel malloc debugging options");
#endif
Add a new kernel option, MALLOC_MAKE_FAILURES, which compiles in a debugging feature causing M_NOWAIT allocations to fail at a specified rate. This can be useful for detecting poor handling of M_NOWAIT: the most frequent problems I've bumped into are unconditional deference of the pointer even though it's NULL, and hangs as a result of a lost event where memory for the event couldn't be allocated. Two sysctls are added: debug.malloc.failure_rate How often to generate a failure: if set to 0 (default), this feature is disabled. Otherwise, the frequency of failures -- I've been using 10 (one in ten mallocs fails), but other popular settings might be much lower or much higher. debug.malloc.failure_count Number of times a coerced malloc failure has occurred as a result of this feature. Useful for tracking what might have happened and whether failures are being generated. Useful possible additions: tying failure rate to malloc type, printfs indicating the thread that experienced the coerced failure. Reviewed by: jeffr, jhb
2003-03-26 20:18:40 +00:00
/*
Expand comments for malloc(9) to better describe the design and statistics / memory types model.
2006-07-23 19:51:39 +00:00
* malloc(9) fault injection -- cause malloc failures every (n) mallocs when
* the caller specifies M_NOWAIT. If set to 0, no failures are caused.
Add a new kernel option, MALLOC_MAKE_FAILURES, which compiles in a debugging feature causing M_NOWAIT allocations to fail at a specified rate. This can be useful for detecting poor handling of M_NOWAIT: the most frequent problems I've bumped into are unconditional deference of the pointer even though it's NULL, and hangs as a result of a lost event where memory for the event couldn't be allocated. Two sysctls are added: debug.malloc.failure_rate How often to generate a failure: if set to 0 (default), this feature is disabled. Otherwise, the frequency of failures -- I've been using 10 (one in ten mallocs fails), but other popular settings might be much lower or much higher. debug.malloc.failure_count Number of times a coerced malloc failure has occurred as a result of this feature. Useful for tracking what might have happened and whether failures are being generated. Useful possible additions: tying failure rate to malloc type, printfs indicating the thread that experienced the coerced failure. Reviewed by: jeffr, jhb
2003-03-26 20:18:40 +00:00
*/
Expand comments for malloc(9) to better describe the design and statistics / memory types model.
2006-07-23 19:51:39 +00:00
#ifdef MALLOC_MAKE_FAILURES
Add a new kernel option, MALLOC_MAKE_FAILURES, which compiles in a debugging feature causing M_NOWAIT allocations to fail at a specified rate. This can be useful for detecting poor handling of M_NOWAIT: the most frequent problems I've bumped into are unconditional deference of the pointer even though it's NULL, and hangs as a result of a lost event where memory for the event couldn't be allocated. Two sysctls are added: debug.malloc.failure_rate How often to generate a failure: if set to 0 (default), this feature is disabled. Otherwise, the frequency of failures -- I've been using 10 (one in ten mallocs fails), but other popular settings might be much lower or much higher. debug.malloc.failure_count Number of times a coerced malloc failure has occurred as a result of this feature. Useful for tracking what might have happened and whether failures are being generated. Useful possible additions: tying failure rate to malloc type, printfs indicating the thread that experienced the coerced failure. Reviewed by: jeffr, jhb
2003-03-26 20:18:40 +00:00
static int malloc_failure_rate;
static int malloc_nowait_count;
static int malloc_failure_count;
Pull in r267961 and r267973 again. Fix for issues reported will follow.
2014-06-28 03:56:17 +00:00
SYSCTL_INT(_debug_malloc, OID_AUTO, failure_rate, CTLFLAG_RWTUN,
Add a new kernel option, MALLOC_MAKE_FAILURES, which compiles in a debugging feature causing M_NOWAIT allocations to fail at a specified rate. This can be useful for detecting poor handling of M_NOWAIT: the most frequent problems I've bumped into are unconditional deference of the pointer even though it's NULL, and hangs as a result of a lost event where memory for the event couldn't be allocated. Two sysctls are added: debug.malloc.failure_rate How often to generate a failure: if set to 0 (default), this feature is disabled. Otherwise, the frequency of failures -- I've been using 10 (one in ten mallocs fails), but other popular settings might be much lower or much higher. debug.malloc.failure_count Number of times a coerced malloc failure has occurred as a result of this feature. Useful for tracking what might have happened and whether failures are being generated. Useful possible additions: tying failure rate to malloc type, printfs indicating the thread that experienced the coerced failure. Reviewed by: jeffr, jhb
2003-03-26 20:18:40 +00:00
&malloc_failure_rate, 0, "Every (n) mallocs with M_NOWAIT will fail");
SYSCTL_INT(_debug_malloc, OID_AUTO, failure_count, CTLFLAG_RD,
&malloc_failure_count, 0, "Number of imposed M_NOWAIT malloc failures");
#endif
vm.kmem_map_size: a sysctl to query current kmem_map->size Based on a patch from Sandvine Incorporated via emaste. Reviewed by: emaste MFC after: 1 week
2010-10-07 18:11:33 +00:00
static int
sysctl_kmem_map_size(SYSCTL_HANDLER_ARGS)
{
u_long size;
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
size = vmem_size(kmem_arena, VMEM_ALLOC);
vm.kmem_map_size: a sysctl to query current kmem_map->size Based on a patch from Sandvine Incorporated via emaste. Reviewed by: emaste MFC after: 1 week
2010-10-07 18:11:33 +00:00
return (sysctl_handle_long(oidp, &size, 0, req));
}
add kmem_map_free sysctl: query largest contiguous free range in kmem_map Suggested by: alc Reviewed by: alc MFC after: 1 week
2010-10-09 09:03:17 +00:00
static int
sysctl_kmem_map_free(SYSCTL_HANDLER_ARGS)
{
u_long size;
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
size = vmem_size(kmem_arena, VMEM_FREE);
add kmem_map_free sysctl: query largest contiguous free range in kmem_map Suggested by: alc Reviewed by: alc MFC after: 1 week
2010-10-09 09:03:17 +00:00
return (sysctl_handle_long(oidp, &size, 0, req));
}
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
/*
* malloc(9) uma zone separation -- sub-page buffer overruns in one
* malloc type will affect only a subset of other malloc types.
*/
#if MALLOC_DEBUG_MAXZONES > 1
static void
tunable_set_numzones(void)
{
TUNABLE_INT_FETCH("debug.malloc.numzones",
&numzones);
/* Sanity check the number of malloc uma zones. */
if (numzones <= 0)
numzones = 1;
if (numzones > MALLOC_DEBUG_MAXZONES)
numzones = MALLOC_DEBUG_MAXZONES;
}
SYSINIT(numzones, SI_SUB_TUNABLES, SI_ORDER_ANY, tunable_set_numzones, NULL);
Pull in r267961 and r267973 again. Fix for issues reported will follow.
2014-06-28 03:56:17 +00:00
SYSCTL_INT(_debug_malloc, OID_AUTO, numzones, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
&numzones, 0, "Number of malloc uma subzones");
/*
* Any number that changes regularly is an okay choice for the
* offset. Build numbers are pretty good of you have them.
*/
static u_int zone_offset = __FreeBSD_version;
TUNABLE_INT("debug.malloc.zone_offset", &zone_offset);
SYSCTL_UINT(_debug_malloc, OID_AUTO, zone_offset, CTLFLAG_RDTUN,
&zone_offset, 0, "Separate malloc types by examining the "
"Nth character in the malloc type short description.");
static u_int
mtp_get_subzone(const char *desc)
{
size_t len;
u_int val;
if (desc == NULL || (len = strlen(desc)) == 0)
return (0);
val = desc[zone_offset % len];
return (val % numzones);
}
#elif MALLOC_DEBUG_MAXZONES == 0
#error "MALLOC_DEBUG_MAXZONES must be positive."
#else
static inline u_int
mtp_get_subzone(const char *desc)
{
return (0);
}
#endif /* MALLOC_DEBUG_MAXZONES > 1 */
Introduce malloc_last_fail() which returns the number of seconds since malloc(9) failed last time. This is intended to help code adjust memory usage to the current circumstances. A typical use could be: if (malloc_last_fail() < 60) reduce_cache_by_one();
2002-11-01 18:58:12 +00:00
int
malloc_last_fail(void)
{
return (time_uptime - t_malloc_fail);
}
Reimplement contigmalloc(9) with an algorithm which stands a greatly- improved chance of working despite pressure from running programs. Instead of trying to throw a bunch of pages out to swap and hope for the best, only a range that can potentially fulfill contigmalloc(9)'s request will have its contents paged out (potentially, not forcibly) at a time. The new contigmalloc operation still operates in three passes, but it could potentially be tuned to more or less. The first pass only looks at pages in the cache and free pages, so they would be thrown out without having to block. If this is not enough, the subsequent passes page out any unwired memory. To combat memory pressure refragmenting the section of memory being laundered, each page is removed from the systems' free memory queue once it has been freed so that blocking later doesn't cause the memory laundered so far to get reallocated. The page-out operations are now blocking, as it would make little sense to try to push out a page, then get its status immediately afterward to remove it from the available free pages queue, if it's unlikely to have been freed. Another change is that if KVA allocation fails, the allocated memory segment will be freed and not leaked. There is a sysctl/tunable, defaulting to on, which causes the old contigmalloc() algorithm to be used. Nonetheless, I have been using vm.old_contigmalloc=0 for over a month. It is safe to switch at run-time to see the difference it makes. A new interface has been used which does not require mapping the allocated pages into KVA: vm_page.h functions vm_page_alloc_contig() and vm_page_release_contig(). These are what vm.old_contigmalloc=0 uses internally, so the sysctl/tunable does not affect their operation. When using the contigmalloc(9) and contigfree(9) interfaces, memory is now tracked with malloc(9) stats. Several functions have been exported from kern_malloc.c to allow other subsystems to use these statistics, as well. This invalidates the BUGS section of the contigmalloc(9) manpage.
2004-07-19 06:21:27 +00:00
/*
Expand comments for malloc(9) to better describe the design and statistics / memory types model.
2006-07-23 19:51:39 +00:00
* An allocation has succeeded -- update malloc type statistics for the
* amount of bucket size. Occurs within a critical section so that the
* thread isn't preempted and doesn't migrate while updating per-PCU
* statistics.
Reimplement contigmalloc(9) with an algorithm which stands a greatly- improved chance of working despite pressure from running programs. Instead of trying to throw a bunch of pages out to swap and hope for the best, only a range that can potentially fulfill contigmalloc(9)'s request will have its contents paged out (potentially, not forcibly) at a time. The new contigmalloc operation still operates in three passes, but it could potentially be tuned to more or less. The first pass only looks at pages in the cache and free pages, so they would be thrown out without having to block. If this is not enough, the subsequent passes page out any unwired memory. To combat memory pressure refragmenting the section of memory being laundered, each page is removed from the systems' free memory queue once it has been freed so that blocking later doesn't cause the memory laundered so far to get reallocated. The page-out operations are now blocking, as it would make little sense to try to push out a page, then get its status immediately afterward to remove it from the available free pages queue, if it's unlikely to have been freed. Another change is that if KVA allocation fails, the allocated memory segment will be freed and not leaked. There is a sysctl/tunable, defaulting to on, which causes the old contigmalloc() algorithm to be used. Nonetheless, I have been using vm.old_contigmalloc=0 for over a month. It is safe to switch at run-time to see the difference it makes. A new interface has been used which does not require mapping the allocated pages into KVA: vm_page.h functions vm_page_alloc_contig() and vm_page_release_contig(). These are what vm.old_contigmalloc=0 uses internally, so the sysctl/tunable does not affect their operation. When using the contigmalloc(9) and contigfree(9) interfaces, memory is now tracked with malloc(9) stats. Several functions have been exported from kern_malloc.c to allow other subsystems to use these statistics, as well. This invalidates the BUGS section of the contigmalloc(9) manpage.
2004-07-19 06:21:27 +00:00
*/
static void
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
malloc_type_zone_allocated(struct malloc_type *mtp, unsigned long size,
Reimplement contigmalloc(9) with an algorithm which stands a greatly- improved chance of working despite pressure from running programs. Instead of trying to throw a bunch of pages out to swap and hope for the best, only a range that can potentially fulfill contigmalloc(9)'s request will have its contents paged out (potentially, not forcibly) at a time. The new contigmalloc operation still operates in three passes, but it could potentially be tuned to more or less. The first pass only looks at pages in the cache and free pages, so they would be thrown out without having to block. If this is not enough, the subsequent passes page out any unwired memory. To combat memory pressure refragmenting the section of memory being laundered, each page is removed from the systems' free memory queue once it has been freed so that blocking later doesn't cause the memory laundered so far to get reallocated. The page-out operations are now blocking, as it would make little sense to try to push out a page, then get its status immediately afterward to remove it from the available free pages queue, if it's unlikely to have been freed. Another change is that if KVA allocation fails, the allocated memory segment will be freed and not leaked. There is a sysctl/tunable, defaulting to on, which causes the old contigmalloc() algorithm to be used. Nonetheless, I have been using vm.old_contigmalloc=0 for over a month. It is safe to switch at run-time to see the difference it makes. A new interface has been used which does not require mapping the allocated pages into KVA: vm_page.h functions vm_page_alloc_contig() and vm_page_release_contig(). These are what vm.old_contigmalloc=0 uses internally, so the sysctl/tunable does not affect their operation. When using the contigmalloc(9) and contigfree(9) interfaces, memory is now tracked with malloc(9) stats. Several functions have been exported from kern_malloc.c to allow other subsystems to use these statistics, as well. This invalidates the BUGS section of the contigmalloc(9) manpage.
2004-07-19 06:21:27 +00:00
int zindx)
{
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
struct malloc_type_internal *mtip;
struct malloc_type_stats *mtsp;
critical_enter();
mtip = mtp->ks_handle;
mtsp = &mtip->mti_stats[curcpu];
Fix the way how "InUse" column in 'vmstat -m' output works: - increase number of allocations count only on successfull malloc(9), so it doesn't confuse people; - because we need to check if 'size > 0', hide 'mtsp->mts_memalloced += size;' under the check as well, as for size=0 it is of course a no-op; - avoid critical_enter()/critical_exit() in case of failure in malloc_type_allocated() as there will be nothing to do. OK'ed by: rwatson MFC after: 2 days
2005-07-27 23:17:31 +00:00
if (size > 0) {
mtsp->mts_memalloced += size;
mtsp->mts_numallocs++;
}
Reimplement contigmalloc(9) with an algorithm which stands a greatly- improved chance of working despite pressure from running programs. Instead of trying to throw a bunch of pages out to swap and hope for the best, only a range that can potentially fulfill contigmalloc(9)'s request will have its contents paged out (potentially, not forcibly) at a time. The new contigmalloc operation still operates in three passes, but it could potentially be tuned to more or less. The first pass only looks at pages in the cache and free pages, so they would be thrown out without having to block. If this is not enough, the subsequent passes page out any unwired memory. To combat memory pressure refragmenting the section of memory being laundered, each page is removed from the systems' free memory queue once it has been freed so that blocking later doesn't cause the memory laundered so far to get reallocated. The page-out operations are now blocking, as it would make little sense to try to push out a page, then get its status immediately afterward to remove it from the available free pages queue, if it's unlikely to have been freed. Another change is that if KVA allocation fails, the allocated memory segment will be freed and not leaked. There is a sysctl/tunable, defaulting to on, which causes the old contigmalloc() algorithm to be used. Nonetheless, I have been using vm.old_contigmalloc=0 for over a month. It is safe to switch at run-time to see the difference it makes. A new interface has been used which does not require mapping the allocated pages into KVA: vm_page.h functions vm_page_alloc_contig() and vm_page_release_contig(). These are what vm.old_contigmalloc=0 uses internally, so the sysctl/tunable does not affect their operation. When using the contigmalloc(9) and contigfree(9) interfaces, memory is now tracked with malloc(9) stats. Several functions have been exported from kern_malloc.c to allow other subsystems to use these statistics, as well. This invalidates the BUGS section of the contigmalloc(9) manpage.
2004-07-19 06:21:27 +00:00
if (zindx != -1)
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
mtsp->mts_size |= 1 << zindx;
Add support for the DTrace malloc provider which can enable probes on a per-malloc type basis.
2008-05-23 00:43:36 +00:00
#ifdef KDTRACE_HOOKS
if (dtrace_malloc_probe != NULL) {
uint32_t probe_id = mtip->mti_probes[DTMALLOC_PROBE_MALLOC];
if (probe_id != 0)
(dtrace_malloc_probe)(probe_id,
(uintptr_t) mtp, (uintptr_t) mtip,
(uintptr_t) mtsp, size, zindx);
}
#endif
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
critical_exit();
Reimplement contigmalloc(9) with an algorithm which stands a greatly- improved chance of working despite pressure from running programs. Instead of trying to throw a bunch of pages out to swap and hope for the best, only a range that can potentially fulfill contigmalloc(9)'s request will have its contents paged out (potentially, not forcibly) at a time. The new contigmalloc operation still operates in three passes, but it could potentially be tuned to more or less. The first pass only looks at pages in the cache and free pages, so they would be thrown out without having to block. If this is not enough, the subsequent passes page out any unwired memory. To combat memory pressure refragmenting the section of memory being laundered, each page is removed from the systems' free memory queue once it has been freed so that blocking later doesn't cause the memory laundered so far to get reallocated. The page-out operations are now blocking, as it would make little sense to try to push out a page, then get its status immediately afterward to remove it from the available free pages queue, if it's unlikely to have been freed. Another change is that if KVA allocation fails, the allocated memory segment will be freed and not leaked. There is a sysctl/tunable, defaulting to on, which causes the old contigmalloc() algorithm to be used. Nonetheless, I have been using vm.old_contigmalloc=0 for over a month. It is safe to switch at run-time to see the difference it makes. A new interface has been used which does not require mapping the allocated pages into KVA: vm_page.h functions vm_page_alloc_contig() and vm_page_release_contig(). These are what vm.old_contigmalloc=0 uses internally, so the sysctl/tunable does not affect their operation. When using the contigmalloc(9) and contigfree(9) interfaces, memory is now tracked with malloc(9) stats. Several functions have been exported from kern_malloc.c to allow other subsystems to use these statistics, as well. This invalidates the BUGS section of the contigmalloc(9) manpage.
2004-07-19 06:21:27 +00:00
}
void
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
malloc_type_allocated(struct malloc_type *mtp, unsigned long size)
Reimplement contigmalloc(9) with an algorithm which stands a greatly- improved chance of working despite pressure from running programs. Instead of trying to throw a bunch of pages out to swap and hope for the best, only a range that can potentially fulfill contigmalloc(9)'s request will have its contents paged out (potentially, not forcibly) at a time. The new contigmalloc operation still operates in three passes, but it could potentially be tuned to more or less. The first pass only looks at pages in the cache and free pages, so they would be thrown out without having to block. If this is not enough, the subsequent passes page out any unwired memory. To combat memory pressure refragmenting the section of memory being laundered, each page is removed from the systems' free memory queue once it has been freed so that blocking later doesn't cause the memory laundered so far to get reallocated. The page-out operations are now blocking, as it would make little sense to try to push out a page, then get its status immediately afterward to remove it from the available free pages queue, if it's unlikely to have been freed. Another change is that if KVA allocation fails, the allocated memory segment will be freed and not leaked. There is a sysctl/tunable, defaulting to on, which causes the old contigmalloc() algorithm to be used. Nonetheless, I have been using vm.old_contigmalloc=0 for over a month. It is safe to switch at run-time to see the difference it makes. A new interface has been used which does not require mapping the allocated pages into KVA: vm_page.h functions vm_page_alloc_contig() and vm_page_release_contig(). These are what vm.old_contigmalloc=0 uses internally, so the sysctl/tunable does not affect their operation. When using the contigmalloc(9) and contigfree(9) interfaces, memory is now tracked with malloc(9) stats. Several functions have been exported from kern_malloc.c to allow other subsystems to use these statistics, as well. This invalidates the BUGS section of the contigmalloc(9) manpage.
2004-07-19 06:21:27 +00:00
{
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
Fix the way how "InUse" column in 'vmstat -m' output works: - increase number of allocations count only on successfull malloc(9), so it doesn't confuse people; - because we need to check if 'size > 0', hide 'mtsp->mts_memalloced += size;' under the check as well, as for size=0 it is of course a no-op; - avoid critical_enter()/critical_exit() in case of failure in malloc_type_allocated() as there will be nothing to do. OK'ed by: rwatson MFC after: 2 days
2005-07-27 23:17:31 +00:00
if (size > 0)
malloc_type_zone_allocated(mtp, size, -1);
Reimplement contigmalloc(9) with an algorithm which stands a greatly- improved chance of working despite pressure from running programs. Instead of trying to throw a bunch of pages out to swap and hope for the best, only a range that can potentially fulfill contigmalloc(9)'s request will have its contents paged out (potentially, not forcibly) at a time. The new contigmalloc operation still operates in three passes, but it could potentially be tuned to more or less. The first pass only looks at pages in the cache and free pages, so they would be thrown out without having to block. If this is not enough, the subsequent passes page out any unwired memory. To combat memory pressure refragmenting the section of memory being laundered, each page is removed from the systems' free memory queue once it has been freed so that blocking later doesn't cause the memory laundered so far to get reallocated. The page-out operations are now blocking, as it would make little sense to try to push out a page, then get its status immediately afterward to remove it from the available free pages queue, if it's unlikely to have been freed. Another change is that if KVA allocation fails, the allocated memory segment will be freed and not leaked. There is a sysctl/tunable, defaulting to on, which causes the old contigmalloc() algorithm to be used. Nonetheless, I have been using vm.old_contigmalloc=0 for over a month. It is safe to switch at run-time to see the difference it makes. A new interface has been used which does not require mapping the allocated pages into KVA: vm_page.h functions vm_page_alloc_contig() and vm_page_release_contig(). These are what vm.old_contigmalloc=0 uses internally, so the sysctl/tunable does not affect their operation. When using the contigmalloc(9) and contigfree(9) interfaces, memory is now tracked with malloc(9) stats. Several functions have been exported from kern_malloc.c to allow other subsystems to use these statistics, as well. This invalidates the BUGS section of the contigmalloc(9) manpage.
2004-07-19 06:21:27 +00:00
}
/*
Spell statistics more correctly in comments.
2007-06-14 03:02:33 +00:00
* A free operation has occurred -- update malloc type statistics for the
Expand comments for malloc(9) to better describe the design and statistics / memory types model.
2006-07-23 19:51:39 +00:00
* amount of the bucket size. Occurs within a critical section so that the
* thread isn't preempted and doesn't migrate while updating per-CPU
* statistics.
Reimplement contigmalloc(9) with an algorithm which stands a greatly- improved chance of working despite pressure from running programs. Instead of trying to throw a bunch of pages out to swap and hope for the best, only a range that can potentially fulfill contigmalloc(9)'s request will have its contents paged out (potentially, not forcibly) at a time. The new contigmalloc operation still operates in three passes, but it could potentially be tuned to more or less. The first pass only looks at pages in the cache and free pages, so they would be thrown out without having to block. If this is not enough, the subsequent passes page out any unwired memory. To combat memory pressure refragmenting the section of memory being laundered, each page is removed from the systems' free memory queue once it has been freed so that blocking later doesn't cause the memory laundered so far to get reallocated. The page-out operations are now blocking, as it would make little sense to try to push out a page, then get its status immediately afterward to remove it from the available free pages queue, if it's unlikely to have been freed. Another change is that if KVA allocation fails, the allocated memory segment will be freed and not leaked. There is a sysctl/tunable, defaulting to on, which causes the old contigmalloc() algorithm to be used. Nonetheless, I have been using vm.old_contigmalloc=0 for over a month. It is safe to switch at run-time to see the difference it makes. A new interface has been used which does not require mapping the allocated pages into KVA: vm_page.h functions vm_page_alloc_contig() and vm_page_release_contig(). These are what vm.old_contigmalloc=0 uses internally, so the sysctl/tunable does not affect their operation. When using the contigmalloc(9) and contigfree(9) interfaces, memory is now tracked with malloc(9) stats. Several functions have been exported from kern_malloc.c to allow other subsystems to use these statistics, as well. This invalidates the BUGS section of the contigmalloc(9) manpage.
2004-07-19 06:21:27 +00:00
*/
void
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
malloc_type_freed(struct malloc_type *mtp, unsigned long size)
Reimplement contigmalloc(9) with an algorithm which stands a greatly- improved chance of working despite pressure from running programs. Instead of trying to throw a bunch of pages out to swap and hope for the best, only a range that can potentially fulfill contigmalloc(9)'s request will have its contents paged out (potentially, not forcibly) at a time. The new contigmalloc operation still operates in three passes, but it could potentially be tuned to more or less. The first pass only looks at pages in the cache and free pages, so they would be thrown out without having to block. If this is not enough, the subsequent passes page out any unwired memory. To combat memory pressure refragmenting the section of memory being laundered, each page is removed from the systems' free memory queue once it has been freed so that blocking later doesn't cause the memory laundered so far to get reallocated. The page-out operations are now blocking, as it would make little sense to try to push out a page, then get its status immediately afterward to remove it from the available free pages queue, if it's unlikely to have been freed. Another change is that if KVA allocation fails, the allocated memory segment will be freed and not leaked. There is a sysctl/tunable, defaulting to on, which causes the old contigmalloc() algorithm to be used. Nonetheless, I have been using vm.old_contigmalloc=0 for over a month. It is safe to switch at run-time to see the difference it makes. A new interface has been used which does not require mapping the allocated pages into KVA: vm_page.h functions vm_page_alloc_contig() and vm_page_release_contig(). These are what vm.old_contigmalloc=0 uses internally, so the sysctl/tunable does not affect their operation. When using the contigmalloc(9) and contigfree(9) interfaces, memory is now tracked with malloc(9) stats. Several functions have been exported from kern_malloc.c to allow other subsystems to use these statistics, as well. This invalidates the BUGS section of the contigmalloc(9) manpage.
2004-07-19 06:21:27 +00:00
{
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
struct malloc_type_internal *mtip;
struct malloc_type_stats *mtsp;
critical_enter();
mtip = mtp->ks_handle;
mtsp = &mtip->mti_stats[curcpu];
mtsp->mts_memfreed += size;
mtsp->mts_numfrees++;
Add support for the DTrace malloc provider which can enable probes on a per-malloc type basis.
2008-05-23 00:43:36 +00:00
#ifdef KDTRACE_HOOKS
if (dtrace_malloc_probe != NULL) {
uint32_t probe_id = mtip->mti_probes[DTMALLOC_PROBE_FREE];
if (probe_id != 0)
(dtrace_malloc_probe)(probe_id,
(uintptr_t) mtp, (uintptr_t) mtip,
(uintptr_t) mtsp, size, 0);
}
#endif
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
critical_exit();
Reimplement contigmalloc(9) with an algorithm which stands a greatly- improved chance of working despite pressure from running programs. Instead of trying to throw a bunch of pages out to swap and hope for the best, only a range that can potentially fulfill contigmalloc(9)'s request will have its contents paged out (potentially, not forcibly) at a time. The new contigmalloc operation still operates in three passes, but it could potentially be tuned to more or less. The first pass only looks at pages in the cache and free pages, so they would be thrown out without having to block. If this is not enough, the subsequent passes page out any unwired memory. To combat memory pressure refragmenting the section of memory being laundered, each page is removed from the systems' free memory queue once it has been freed so that blocking later doesn't cause the memory laundered so far to get reallocated. The page-out operations are now blocking, as it would make little sense to try to push out a page, then get its status immediately afterward to remove it from the available free pages queue, if it's unlikely to have been freed. Another change is that if KVA allocation fails, the allocated memory segment will be freed and not leaked. There is a sysctl/tunable, defaulting to on, which causes the old contigmalloc() algorithm to be used. Nonetheless, I have been using vm.old_contigmalloc=0 for over a month. It is safe to switch at run-time to see the difference it makes. A new interface has been used which does not require mapping the allocated pages into KVA: vm_page.h functions vm_page_alloc_contig() and vm_page_release_contig(). These are what vm.old_contigmalloc=0 uses internally, so the sysctl/tunable does not affect their operation. When using the contigmalloc(9) and contigfree(9) interfaces, memory is now tracked with malloc(9) stats. Several functions have been exported from kern_malloc.c to allow other subsystems to use these statistics, as well. This invalidates the BUGS section of the contigmalloc(9) manpage.
2004-07-19 06:21:27 +00:00
}
contigmalloc(9) and contigfree(9) are now implemented in terms of other more general VM system interfaces. So, their implementation can now reside in kern_malloc.c alongside the other functions that are declared in malloc.h.
2011-10-27 02:52:24 +00:00
/*
* contigmalloc:
*
* Allocate a block of physically contiguous memory.
*
* If M_NOWAIT is set, this routine will not block and return NULL if
* the allocation fails.
*/
void *
contigmalloc(unsigned long size, struct malloc_type *type, int flags,
vm_paddr_t low, vm_paddr_t high, unsigned long alignment,
- Change contigmalloc() to use the vm_paddr_t type instead of an unsigned long for specifying a boundary constraint. - Change bus_dma tags to use bus_addr_t instead of bus_size_t for boundary constraints. These allow boundary constraints to be fully expressed for cases where sizeof(bus_addr_t) != sizeof(bus_size_t). Specifically, it allows a driver to properly specify a 4GB boundary in a PAE kernel. Note that this cannot be safely MFC'd without a lot of compat shims due to KBI changes, so I do not intend to merge it. Reviewed by: scottl
2012-03-01 19:58:34 +00:00
vm_paddr_t boundary)
contigmalloc(9) and contigfree(9) are now implemented in terms of other more general VM system interfaces. So, their implementation can now reside in kern_malloc.c alongside the other functions that are declared in malloc.h.
2011-10-27 02:52:24 +00:00
{
void *ret;
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
ret = (void *)kmem_alloc_contig(kernel_arena, size, flags, low, high,
contigmalloc(9) and contigfree(9) are now implemented in terms of other more general VM system interfaces. So, their implementation can now reside in kern_malloc.c alongside the other functions that are declared in malloc.h.
2011-10-27 02:52:24 +00:00
alignment, boundary, VM_MEMATTR_DEFAULT);
if (ret != NULL)
malloc_type_allocated(type, round_page(size));
return (ret);
}
/*
* contigfree:
*
* Free a block of memory allocated by contigmalloc.
*
* This routine may not block.
*/
void
contigfree(void *addr, unsigned long size, struct malloc_type *type)
{
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
kmem_free(kernel_arena, (vm_offset_t)addr, size);
contigmalloc(9) and contigfree(9) are now implemented in terms of other more general VM system interfaces. So, their implementation can now reside in kern_malloc.c alongside the other functions that are declared in malloc.h.
2011-10-27 02:52:24 +00:00
malloc_type_freed(type, round_page(size));
}
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
/*
This is a rather large commit that encompasses the new swapper, changes to the VM system to support the new swapper, VM bug fixes, several VM optimizations, and some additional revamping of the VM code. The specific bug fixes will be documented with additional forced commits. This commit is somewhat rough in regards to code cleanup issues. Reviewed by: "John S. Dyson" <root@dyson.iquest.net>, "David Greenman" <dg@root.com>
1999-01-21 08:29:12 +00:00
* malloc:
*
* Allocate a block of memory.
*
* If M_NOWAIT is set, this routine will not block and return NULL if
* the allocation fails.
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
*/
void *
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
malloc(unsigned long size, struct malloc_type *mtp, int flags)
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
{
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
int indx;
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
struct malloc_type_internal *mtip;
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
caddr_t va;
uma_zone_t zone;
Add buffer corruption protection (RedZone) for kernel's malloc(9). It detects both: buffer underflows and buffer overflows bugs at runtime (on free(9) and realloc(9)) and prints backtraces from where memory was allocated and from where it was freed. Tested by: kris
2006-01-31 11:09:21 +00:00
#if defined(DIAGNOSTIC) || defined(DEBUG_REDZONE)
Under #ifdef DIAGNOSTIC, fill malloc(9) allocations which do not have M_ZERO specified with 0x70. (malloc_flags=J for the kernel :-)
2003-02-01 10:07:49 +00:00
unsigned long osize = size;
#endif
Make malloc more extensible. The malloc type is now a pointer to the struct kmemstats that describes the type. This allows subsystems to declare their malloc types locally and <sys/malloc.h> doesn't need tweaked everytime somebody gets an idea. You can even have a type local to a lkm... I don't know if we really need the longdesc, comments welcome. TODO: There is a single nit in ext2fs, that will be fixed later, and I intend to remove all unused malloc types and distribute the rest closer to their use.
1997-10-10 14:06:34 +00:00
PHCC[1]: I had commented the #ifdef INVARIANTS checks out to make sure I ran this code in all kernels and forgot to comment the #ifdefs back in before I committed. Spotted by: bmilekic [1] PHCC = Pointy Hat Correction Commit
2003-03-10 20:24:54 +00:00
#ifdef INVARIANTS
struct malloc_type has had a 'magic' field statically initialized to M_MAGIC by MALLOC_DEFINE() for a long time; add assertions that malloc_type's passed to malloc(), free(), etc have that magic set. MFC after: 2 weeks
2009-04-19 12:41:37 +00:00
KASSERT(mtp->ks_magic == M_MAGIC, ("malloc: bad malloc type magic"));
Make malloc and mbuf allocation mode flags nonoverlapping. Under INVARIANTS whine if we get incompatible flags. Submitted by: imp
2003-03-10 19:39:53 +00:00
/*
Long overdue, keep up with mbuf.h,v 1.148.
2005-08-02 20:03:23 +00:00
* Check that exactly one of M_WAITOK or M_NOWAIT is specified.
Make malloc and mbuf allocation mode flags nonoverlapping. Under INVARIANTS whine if we get incompatible flags. Submitted by: imp
2003-03-10 19:39:53 +00:00
*/
Long overdue, keep up with mbuf.h,v 1.148.
2005-08-02 20:03:23 +00:00
indx = flags & (M_WAITOK | M_NOWAIT);
Make malloc and mbuf allocation mode flags nonoverlapping. Under INVARIANTS whine if we get incompatible flags. Submitted by: imp
2003-03-10 19:39:53 +00:00
if (indx != M_NOWAIT && indx != M_WAITOK) {
static struct timeval lasterr;
static int curerr, once;
if (once == 0 && ppsratecheck(&lasterr, &curerr, 1)) {
printf("Bad malloc flags: %x\n", indx);
Update for the KDB framework: o Make debugging code conditional upon KDB instead of DDB. o Call kdb_enter() instead of Debugger(). o Call kdb_backtrace() instead of db_print_backtrace() or backtrace(). kern_mutex.c: o Replace checks for db_active with checks for kdb_active and make them unconditional. kern_shutdown.c: o s/DDB_UNATTENDED/KDB_UNATTENDED/g o s/DDB_TRACE/KDB_TRACE/g o Save the TID of the thread doing the kernel dump so the debugger knows which thread to select as the current when debugging the kernel core file. o Clear kdb_active instead of db_active and do so unconditionally. o Remove backtrace() implementation. kern_synch.c: o Call kdb_reenter() instead of db_error().
2004-07-10 21:36:01 +00:00
kdb_backtrace();
Make malloc and mbuf allocation mode flags nonoverlapping. Under INVARIANTS whine if we get incompatible flags. Submitted by: imp
2003-03-10 19:39:53 +00:00
flags |= M_WAITOK;
once++;
}
}
PHCC[1]: I had commented the #ifdef INVARIANTS checks out to make sure I ran this code in all kernels and forgot to comment the #ifdefs back in before I committed. Spotted by: bmilekic [1] PHCC = Pointy Hat Correction Commit
2003-03-10 20:24:54 +00:00
#endif
Add a new kernel option, MALLOC_MAKE_FAILURES, which compiles in a debugging feature causing M_NOWAIT allocations to fail at a specified rate. This can be useful for detecting poor handling of M_NOWAIT: the most frequent problems I've bumped into are unconditional deference of the pointer even though it's NULL, and hangs as a result of a lost event where memory for the event couldn't be allocated. Two sysctls are added: debug.malloc.failure_rate How often to generate a failure: if set to 0 (default), this feature is disabled. Otherwise, the frequency of failures -- I've been using 10 (one in ten mallocs fails), but other popular settings might be much lower or much higher. debug.malloc.failure_count Number of times a coerced malloc failure has occurred as a result of this feature. Useful for tracking what might have happened and whether failures are being generated. Useful possible additions: tying failure rate to malloc type, printfs indicating the thread that experienced the coerced failure. Reviewed by: jeffr, jhb
2003-03-26 20:18:40 +00:00
#ifdef MALLOC_MAKE_FAILURES
if ((flags & M_NOWAIT) && (malloc_failure_rate != 0)) {
atomic_add_int(&malloc_nowait_count, 1);
if ((malloc_nowait_count % malloc_failure_rate) == 0) {
atomic_add_int(&malloc_failure_count, 1);
Update the "last malloc failure timestamp" also for simulated malloc errors.
2003-04-25 21:49:24 +00:00
t_malloc_fail = time_uptime;
Add a new kernel option, MALLOC_MAKE_FAILURES, which compiles in a debugging feature causing M_NOWAIT allocations to fail at a specified rate. This can be useful for detecting poor handling of M_NOWAIT: the most frequent problems I've bumped into are unconditional deference of the pointer even though it's NULL, and hangs as a result of a lost event where memory for the event couldn't be allocated. Two sysctls are added: debug.malloc.failure_rate How often to generate a failure: if set to 0 (default), this feature is disabled. Otherwise, the frequency of failures -- I've been using 10 (one in ten mallocs fails), but other popular settings might be much lower or much higher. debug.malloc.failure_count Number of times a coerced malloc failure has occurred as a result of this feature. Useful for tracking what might have happened and whether failures are being generated. Useful possible additions: tying failure rate to malloc type, printfs indicating the thread that experienced the coerced failure. Reviewed by: jeffr, jhb
2003-03-26 20:18:40 +00:00
return (NULL);
}
}
Add a basic sanity check on pointers passed to free(9). Should be improved by: jeff
2002-04-23 18:50:25 +00:00
#endif
Make malloc and mbuf allocation mode flags nonoverlapping. Under INVARIANTS whine if we get incompatible flags. Submitted by: imp
2003-03-10 19:39:53 +00:00
if (flags & M_WAITOK)
KSE Milestone 2 Note ALL MODULES MUST BE RECOMPILED make the kernel aware that there are smaller units of scheduling than the process. (but only allow one thread per process at this time). This is functionally equivalent to teh previousl -current except that there is a thread associated with each process. Sorry john! (your next MFC will be a doosie!) Reviewed by: peter@freebsd.org, dillon@freebsd.org X-MFC after: ha ha ha ha
2001-09-12 08:38:13 +00:00
KASSERT(curthread->td_intr_nesting_level == 0,
Back out M_* changes, per decision of the TRB. Approved by: trb
2003-02-19 05:47:46 +00:00
("malloc(M_WAITOK) in interrupt context"));
Don't make assertions about td_critnest when the scheduler is stopped. A panicking thread always executes with a critical section held, so any attempt to allocate or free memory while dumping will otherwise cause a second panic. This can occur, for example, if xpt_polled_action() completes non-dump I/O that was pending at the time of the panic. The fact that this can occur is itself a bug, but asserting in this case does little but reduce the reliability of kernel dumps. Suggested by: kib Reported by: pho
2015-12-11 20:05:07 +00:00
KASSERT(curthread->td_critnest == 0 || SCHEDULER_STOPPED(),
Consistently enforce the restriction against calling malloc/free when in a critical section. uma_zalloc_arg()/uma_zalloc_free() may acquire a sleepable lock on the zone. The malloc() family of functions may call uma_zalloc_arg() or uma_zalloc_free(). The malloc(9) man page currently claims that free() will never sleep. It also implies that the malloc() family of functions will not sleep when called with M_NOWAIT. However, it is more correct to say that these functions will not sleep indefinitely. Indeed, they may acquire a sleepable lock. However, a developer may overlook this restriction because the WITNESS check that catches attempts to call the malloc() family of functions within a critical section is inconsistenly applied. This change clarifies the language of the malloc(9) man page to clarify the restriction against calling the malloc() family of functions while in a critical section or holding a spin lock. It also adds KASSERTs at appropriate points to make the enforcement of this restriction more consistent. PR: 204633 Differential Revision: https://reviews.freebsd.org/D4197 Reviewed by: markj Approved by: gnn (mentor) Sponsored by: Juniper Networks
2015-11-19 14:04:53 +00:00
("malloc: called with spinlock or critical section held"));
Bring in MemGuard, a very simple and small replacement allocator designed to help detect tamper-after-free scenarios, a problem more and more common and likely with multithreaded kernels where race conditions are more prevalent. Currently MemGuard can only take over malloc()/realloc()/free() for particular (a) malloc type(s) and the code brought in with this change manually instruments it to take over M_SUBPROC allocations as an example. If you are planning to use it, for now you must: 1) Put "options DEBUG_MEMGUARD" in your kernel config. 2) Edit src/sys/kern/kern_malloc.c manually, look for "XXX CHANGEME" and replace the M_SUBPROC comparison with the appropriate malloc type (this might require additional but small/simple code modification if, say, the malloc type is declared out of scope). 3) Build and install your kernel. Tune vm.memguard_divisor boot-time tunable which is used to scale how much of kmem_map you want to allott for MemGuard's use. The default is 10, so kmem_size/10. ToDo: 1) Bring in a memguard(9) man page. 2) Better instrumentation (e.g., boot-time) of MemGuard taking over malloc types. 3) Teach UMA about MemGuard to allow MemGuard to override zone allocations too. 4) Improve MemGuard if necessary. This work is partly based on some old patches from Ian Dowse.
2005-01-21 18:09:17 +00:00
#ifdef DEBUG_MEMGUARD
Make memguard(9) capable to guard uma(9) allocations.
2011-10-12 18:08:28 +00:00
if (memguard_cmp_mtp(mtp, size)) {
Rework memguard(9) to reserve significantly more KVA to detect use-after-free over a longer time. Also release the backing pages of a guarded allocation at free(9) time to reduce the overhead of using memguard(9). Allow setting and varying the malloc type at run-time. Add knobs to allow: - randomly guarding memory - adding un-backed KVA guard pages to detect underflow and overflow - a lower limit on the size of allocations that are guarded Reviewed by: alc Reviewed by: brueffer, Ulrich Spörlein <uqs spoerlein net> (man page) Silence from: -arch Approved by: zml (mentor) MFC after: 1 month
2010-08-11 22:10:37 +00:00
va = memguard_alloc(size, flags);
if (va != NULL)
return (va);
/* This is unfortunate but should not be fatal. */
}
Bring in MemGuard, a very simple and small replacement allocator designed to help detect tamper-after-free scenarios, a problem more and more common and likely with multithreaded kernels where race conditions are more prevalent. Currently MemGuard can only take over malloc()/realloc()/free() for particular (a) malloc type(s) and the code brought in with this change manually instruments it to take over M_SUBPROC allocations as an example. If you are planning to use it, for now you must: 1) Put "options DEBUG_MEMGUARD" in your kernel config. 2) Edit src/sys/kern/kern_malloc.c manually, look for "XXX CHANGEME" and replace the M_SUBPROC comparison with the appropriate malloc type (this might require additional but small/simple code modification if, say, the malloc type is declared out of scope). 3) Build and install your kernel. Tune vm.memguard_divisor boot-time tunable which is used to scale how much of kmem_map you want to allott for MemGuard's use. The default is 10, so kmem_size/10. ToDo: 1) Bring in a memguard(9) man page. 2) Better instrumentation (e.g., boot-time) of MemGuard taking over malloc types. 3) Teach UMA about MemGuard to allow MemGuard to override zone allocations too. 4) Improve MemGuard if necessary. This work is partly based on some old patches from Ian Dowse.
2005-01-21 18:09:17 +00:00
#endif
Add buffer corruption protection (RedZone) for kernel's malloc(9). It detects both: buffer underflows and buffer overflows bugs at runtime (on free(9) and realloc(9)) and prints backtraces from where memory was allocated and from where it was freed. Tested by: kris
2006-01-31 11:09:21 +00:00
#ifdef DEBUG_REDZONE
size = redzone_size_ntor(size);
#endif
Add a new loader tunable, vm.kmem_zmax which allows a system administrator to limit the maximum allocation size that malloc(9) would consider using the UMA cache allocator as backend. Suggested by: alfred MFC after: 2 weeks
2014-08-14 05:31:39 +00:00
if (size <= kmem_zmax) {
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
mtip = mtp->ks_handle;
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
if (size & KMEM_ZMASK)
size = (size & ~KMEM_ZMASK) + KMEM_ZBASE;
indx = kmemsize[size >> KMEM_ZSHIFT];
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
KASSERT(mtip->mti_zone < numzones,
("mti_zone %u out of range %d",
mtip->mti_zone, numzones));
zone = kmemzones[indx].kz_zone[mtip->mti_zone];
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
#ifdef MALLOC_PROFILE
krequests[size >> KMEM_ZSHIFT]++;
#endif
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
va = uma_zalloc(zone, flags);
Reimplement contigmalloc(9) with an algorithm which stands a greatly- improved chance of working despite pressure from running programs. Instead of trying to throw a bunch of pages out to swap and hope for the best, only a range that can potentially fulfill contigmalloc(9)'s request will have its contents paged out (potentially, not forcibly) at a time. The new contigmalloc operation still operates in three passes, but it could potentially be tuned to more or less. The first pass only looks at pages in the cache and free pages, so they would be thrown out without having to block. If this is not enough, the subsequent passes page out any unwired memory. To combat memory pressure refragmenting the section of memory being laundered, each page is removed from the systems' free memory queue once it has been freed so that blocking later doesn't cause the memory laundered so far to get reallocated. The page-out operations are now blocking, as it would make little sense to try to push out a page, then get its status immediately afterward to remove it from the available free pages queue, if it's unlikely to have been freed. Another change is that if KVA allocation fails, the allocated memory segment will be freed and not leaked. There is a sysctl/tunable, defaulting to on, which causes the old contigmalloc() algorithm to be used. Nonetheless, I have been using vm.old_contigmalloc=0 for over a month. It is safe to switch at run-time to see the difference it makes. A new interface has been used which does not require mapping the allocated pages into KVA: vm_page.h functions vm_page_alloc_contig() and vm_page_release_contig(). These are what vm.old_contigmalloc=0 uses internally, so the sysctl/tunable does not affect their operation. When using the contigmalloc(9) and contigfree(9) interfaces, memory is now tracked with malloc(9) stats. Several functions have been exported from kern_malloc.c to allow other subsystems to use these statistics, as well. This invalidates the BUGS section of the contigmalloc(9) manpage.
2004-07-19 06:21:27 +00:00
if (va != NULL)
- Make the keg abstraction more complete. Permit a zone to have multiple backend kegs so it may source compatible memory from multiple backends. This is useful for cases such as NUMA or different layouts for the same memory type. - Provide a new api for adding new backend kegs to secondary zones. - Provide a new flag for adjusting the layout of zones to stagger allocations better across cache lines. Sponsored by: Nokia
2009-01-25 09:11:24 +00:00
size = zone->uz_size;
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
malloc_type_zone_allocated(mtp, va == NULL ? 0 : size, indx);
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
} else {
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
size = roundup(size, PAGE_SIZE);
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
zone = NULL;
va = uma_large_malloc(size, flags);
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
malloc_type_allocated(mtp, va == NULL ? 0 : size);
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
}
Don't pass NULL pointer to memset if we are compiled with DIAGNOSTIC Approved by: re/rwatson
2003-05-12 05:09:56 +00:00
if (flags & M_WAITOK)
Back out M_* changes, per decision of the TRB. Approved by: trb
2003-02-19 05:47:46 +00:00
KASSERT(va != NULL, ("malloc(M_WAITOK) returned NULL"));
Don't pass NULL pointer to memset if we are compiled with DIAGNOSTIC Approved by: re/rwatson
2003-05-12 05:09:56 +00:00
else if (va == NULL)
Introduce malloc_last_fail() which returns the number of seconds since malloc(9) failed last time. This is intended to help code adjust memory usage to the current circumstances. A typical use could be: if (malloc_last_fail() < 60) reduce_cache_by_one();
2002-11-01 18:58:12 +00:00
t_malloc_fail = time_uptime;
Under #ifdef DIAGNOSTIC, fill malloc(9) allocations which do not have M_ZERO specified with 0x70. (malloc_flags=J for the kernel :-)
2003-02-01 10:07:49 +00:00
#ifdef DIAGNOSTIC
Don't pass NULL pointer to memset if we are compiled with DIAGNOSTIC Approved by: re/rwatson
2003-05-12 05:09:56 +00:00
if (va != NULL && !(flags & M_ZERO)) {
Under #ifdef DIAGNOSTIC, fill malloc(9) allocations which do not have M_ZERO specified with 0x70. (malloc_flags=J for the kernel :-)
2003-02-01 10:07:49 +00:00
memset(va, 0x70, osize);
}
Add buffer corruption protection (RedZone) for kernel's malloc(9). It detects both: buffer underflows and buffer overflows bugs at runtime (on free(9) and realloc(9)) and prints backtraces from where memory was allocated and from where it was freed. Tested by: kris
2006-01-31 11:09:21 +00:00
#endif
#ifdef DEBUG_REDZONE
if (va != NULL)
va = redzone_setup(va, osize);
Under #ifdef DIAGNOSTIC, fill malloc(9) allocations which do not have M_ZERO specified with 0x70. (malloc_flags=J for the kernel :-)
2003-02-01 10:07:49 +00:00
#endif
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
return ((void *) va);
}
/*
This is a rather large commit that encompasses the new swapper, changes to the VM system to support the new swapper, VM bug fixes, several VM optimizations, and some additional revamping of the VM code. The specific bug fixes will be documented with additional forced commits. This commit is somewhat rough in regards to code cleanup issues. Reviewed by: "John S. Dyson" <root@dyson.iquest.net>, "David Greenman" <dg@root.com>
1999-01-21 08:29:12 +00:00
* free:
*
* Free a block of memory allocated by malloc.
*
* This routine may not block.
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
*/
void
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
free(void *addr, struct malloc_type *mtp)
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
{
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
uma_slab_t slab;
u_long size;
Make malloc more extensible. The malloc type is now a pointer to the struct kmemstats that describes the type. This allows subsystems to declare their malloc types locally and <sys/malloc.h> doesn't need tweaked everytime somebody gets an idea. You can even have a type local to a lkm... I don't know if we really need the longdesc, comments welcome. TODO: There is a single nit in ext2fs, that will be fixed later, and I intend to remove all unused malloc types and distribute the rest closer to their use.
1997-10-10 14:06:34 +00:00
struct malloc_type has had a 'magic' field statically initialized to M_MAGIC by MALLOC_DEFINE() for a long time; add assertions that malloc_type's passed to malloc(), free(), etc have that magic set. MFC after: 2 weeks
2009-04-19 12:41:37 +00:00
KASSERT(mtp->ks_magic == M_MAGIC, ("free: bad malloc type magic"));
Don't make assertions about td_critnest when the scheduler is stopped. A panicking thread always executes with a critical section held, so any attempt to allocate or free memory while dumping will otherwise cause a second panic. This can occur, for example, if xpt_polled_action() completes non-dump I/O that was pending at the time of the panic. The fact that this can occur is itself a bug, but asserting in this case does little but reduce the reliability of kernel dumps. Suggested by: kib Reported by: pho
2015-12-11 20:05:07 +00:00
KASSERT(curthread->td_critnest == 0 || SCHEDULER_STOPPED(),
Consistently enforce the restriction against calling malloc/free when in a critical section. uma_zalloc_arg()/uma_zalloc_free() may acquire a sleepable lock on the zone. The malloc() family of functions may call uma_zalloc_arg() or uma_zalloc_free(). The malloc(9) man page currently claims that free() will never sleep. It also implies that the malloc() family of functions will not sleep when called with M_NOWAIT. However, it is more correct to say that these functions will not sleep indefinitely. Indeed, they may acquire a sleepable lock. However, a developer may overlook this restriction because the WITNESS check that catches attempts to call the malloc() family of functions within a critical section is inconsistenly applied. This change clarifies the language of the malloc(9) man page to clarify the restriction against calling the malloc() family of functions while in a critical section or holding a spin lock. It also adds KASSERTs at appropriate points to make the enforcement of this restriction more consistent. PR: 204633 Differential Revision: https://reviews.freebsd.org/D4197 Reviewed by: markj Approved by: gnn (mentor) Sponsored by: Juniper Networks
2015-11-19 14:04:53 +00:00
("free: called with spinlock or critical section held"));
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
/* free(NULL, ...) does nothing */
if (addr == NULL)
return;
Bring in MemGuard, a very simple and small replacement allocator designed to help detect tamper-after-free scenarios, a problem more and more common and likely with multithreaded kernels where race conditions are more prevalent. Currently MemGuard can only take over malloc()/realloc()/free() for particular (a) malloc type(s) and the code brought in with this change manually instruments it to take over M_SUBPROC allocations as an example. If you are planning to use it, for now you must: 1) Put "options DEBUG_MEMGUARD" in your kernel config. 2) Edit src/sys/kern/kern_malloc.c manually, look for "XXX CHANGEME" and replace the M_SUBPROC comparison with the appropriate malloc type (this might require additional but small/simple code modification if, say, the malloc type is declared out of scope). 3) Build and install your kernel. Tune vm.memguard_divisor boot-time tunable which is used to scale how much of kmem_map you want to allott for MemGuard's use. The default is 10, so kmem_size/10. ToDo: 1) Bring in a memguard(9) man page. 2) Better instrumentation (e.g., boot-time) of MemGuard taking over malloc types. 3) Teach UMA about MemGuard to allow MemGuard to override zone allocations too. 4) Improve MemGuard if necessary. This work is partly based on some old patches from Ian Dowse.
2005-01-21 18:09:17 +00:00
#ifdef DEBUG_MEMGUARD
Rework memguard(9) to reserve significantly more KVA to detect use-after-free over a longer time. Also release the backing pages of a guarded allocation at free(9) time to reduce the overhead of using memguard(9). Allow setting and varying the malloc type at run-time. Add knobs to allow: - randomly guarding memory - adding un-backed KVA guard pages to detect underflow and overflow - a lower limit on the size of allocations that are guarded Reviewed by: alc Reviewed by: brueffer, Ulrich Spörlein <uqs spoerlein net> (man page) Silence from: -arch Approved by: zml (mentor) MFC after: 1 month
2010-08-11 22:10:37 +00:00
if (is_memguard_addr(addr)) {
Bring in MemGuard, a very simple and small replacement allocator designed to help detect tamper-after-free scenarios, a problem more and more common and likely with multithreaded kernels where race conditions are more prevalent. Currently MemGuard can only take over malloc()/realloc()/free() for particular (a) malloc type(s) and the code brought in with this change manually instruments it to take over M_SUBPROC allocations as an example. If you are planning to use it, for now you must: 1) Put "options DEBUG_MEMGUARD" in your kernel config. 2) Edit src/sys/kern/kern_malloc.c manually, look for "XXX CHANGEME" and replace the M_SUBPROC comparison with the appropriate malloc type (this might require additional but small/simple code modification if, say, the malloc type is declared out of scope). 3) Build and install your kernel. Tune vm.memguard_divisor boot-time tunable which is used to scale how much of kmem_map you want to allott for MemGuard's use. The default is 10, so kmem_size/10. ToDo: 1) Bring in a memguard(9) man page. 2) Better instrumentation (e.g., boot-time) of MemGuard taking over malloc types. 3) Teach UMA about MemGuard to allow MemGuard to override zone allocations too. 4) Improve MemGuard if necessary. This work is partly based on some old patches from Ian Dowse.
2005-01-21 18:09:17 +00:00
memguard_free(addr);
return;
}
#endif
Add buffer corruption protection (RedZone) for kernel's malloc(9). It detects both: buffer underflows and buffer overflows bugs at runtime (on free(9) and realloc(9)) and prints backtraces from where memory was allocated and from where it was freed. Tested by: kris
2006-01-31 11:09:21 +00:00
#ifdef DEBUG_REDZONE
redzone_check(addr);
addr = redzone_addr_ntor(addr);
#endif
- Split UMA_ZFLAG_OFFPAGE into UMA_ZFLAG_OFFPAGE and UMA_ZFLAG_HASH. - Remove all instances of the mallochash. - Stash the slab pointer in the vm page's object pointer when allocating from the kmem_obj. - Use the overloaded object pointer to find slabs for malloced memory.
2002-09-18 08:26:30 +00:00
slab = vtoslab((vm_offset_t)addr & (~UMA_SLAB_MASK));
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
if (slab == NULL)
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
panic("free: address %p(%p) has not been allocated.\n",
- Split UMA_ZFLAG_OFFPAGE into UMA_ZFLAG_OFFPAGE and UMA_ZFLAG_HASH. - Remove all instances of the mallochash. - Stash the slab pointer in the vm page's object pointer when allocating from the kmem_obj. - Use the overloaded object pointer to find slabs for malloced memory.
2002-09-18 08:26:30 +00:00
addr, (void *)((u_long)addr & (~UMA_SLAB_MASK)));
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
if (!(slab->us_flags & UMA_SLAB_MALLOC)) {
Hide a pointer to the malloc_type bucket at the end of the freed memory. If this memory is modified after it has been freed we can now report it's previous owner.
2002-05-02 09:07:04 +00:00
#ifdef INVARIANTS
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
struct malloc_type **mtpp = addr;
Hide a pointer to the malloc_type bucket at the end of the freed memory. If this memory is modified after it has been freed we can now report it's previous owner.
2002-05-02 09:07:04 +00:00
#endif
Bring in mbuma to replace mballoc. mbuma is an Mbuf & Cluster allocator built on top of a number of extensions to the UMA framework, all included herein. Extensions to UMA worth noting: - Better layering between slab <-> zone caches; introduce Keg structure which splits off slab cache away from the zone structure and allows multiple zones to be stacked on top of a single Keg (single type of slab cache); perhaps we should look into defining a subset API on top of the Keg for special use by malloc(9), for example. - UMA_ZONE_REFCNT zones can now be added, and reference counters automagically allocated for them within the end of the associated slab structures. uma_find_refcnt() does a kextract to fetch the slab struct reference from the underlying page, and lookup the corresponding refcnt. mbuma things worth noting: - integrates mbuf & cluster allocations with extended UMA and provides caches for commonly-allocated items; defines several zones (two primary, one secondary) and two kegs. - change up certain code paths that always used to do: m_get() + m_clget() to instead just use m_getcl() and try to take advantage of the newly defined secondary Packet zone. - netstat(1) and systat(1) quickly hacked up to do basic stat reporting but additional stats work needs to be done once some other details within UMA have been taken care of and it becomes clearer to how stats will work within the modified framework. From the user perspective, one implication is that the NMBCLUSTERS compile-time option is no longer used. The maximum number of clusters is still capped off according to maxusers, but it can be made unlimited by setting the kern.ipc.nmbclusters boot-time tunable to zero. Work should be done to write an appropriate sysctl handler allowing dynamic tuning of kern.ipc.nmbclusters at runtime. Additional things worth noting/known issues (READ): - One report of 'ips' (ServeRAID) driver acting really slow in conjunction with mbuma. Need more data. Latest report is that ips is equally sucking with and without mbuma. - Giant leak in NFS code sometimes occurs, can't reproduce but currently analyzing; brueffer is able to reproduce but THIS IS NOT an mbuma-specific problem and currently occurs even WITHOUT mbuma. - Issues in network locking: there is at least one code path in the rip code where one or more locks are acquired and we end up in m_prepend() with M_WAITOK, which causes WITNESS to whine from within UMA. Current temporary solution: force all UMA allocations to be M_NOWAIT from within UMA for now to avoid deadlocks unless WITNESS is defined and we can determine with certainty that we're not holding any locks when we're M_WAITOK. - I've seen at least one weird socketbuffer empty-but- mbuf-still-attached panic. I don't believe this to be related to mbuma but please keep your eyes open, turn on debugging, and capture crash dumps. This change removes more code than it adds. A paper is available detailing the change and considering various performance issues, it was presented at BSDCan2004: http://www.unixdaemons.com/~bmilekic/netbuf_bmilekic.pdf Please read the paper for Future Work and implementation details, as well as credits. Testing and Debugging: rwatson, brueffer, Ketrien I. Saihr-Kesenchedra, ... Reviewed by: Lots of people (for different parts)
2004-05-31 21:46:06 +00:00
size = slab->us_keg->uk_size;
Hide a pointer to the malloc_type bucket at the end of the freed memory. If this memory is modified after it has been freed we can now report it's previous owner.
2002-05-02 09:07:04 +00:00
#ifdef INVARIANTS
/*
* Cache a pointer to the malloc_type that most recently freed
* this memory here. This way we know who is most likely to
* have stepped on it later.
*
* This code assumes that size is a multiple of 8 bytes for
* 64 bit machines
*/
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
mtpp = (struct malloc_type **)
((unsigned long)mtpp & ~UMA_ALIGN_PTR);
mtpp += (size - sizeof(struct malloc_type *)) /
Hide a pointer to the malloc_type bucket at the end of the freed memory. If this memory is modified after it has been freed we can now report it's previous owner.
2002-05-02 09:07:04 +00:00
sizeof(struct malloc_type *);
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
*mtpp = mtp;
Hide a pointer to the malloc_type bucket at the end of the freed memory. If this memory is modified after it has been freed we can now report it's previous owner.
2002-05-02 09:07:04 +00:00
#endif
Bring in mbuma to replace mballoc. mbuma is an Mbuf & Cluster allocator built on top of a number of extensions to the UMA framework, all included herein. Extensions to UMA worth noting: - Better layering between slab <-> zone caches; introduce Keg structure which splits off slab cache away from the zone structure and allows multiple zones to be stacked on top of a single Keg (single type of slab cache); perhaps we should look into defining a subset API on top of the Keg for special use by malloc(9), for example. - UMA_ZONE_REFCNT zones can now be added, and reference counters automagically allocated for them within the end of the associated slab structures. uma_find_refcnt() does a kextract to fetch the slab struct reference from the underlying page, and lookup the corresponding refcnt. mbuma things worth noting: - integrates mbuf & cluster allocations with extended UMA and provides caches for commonly-allocated items; defines several zones (two primary, one secondary) and two kegs. - change up certain code paths that always used to do: m_get() + m_clget() to instead just use m_getcl() and try to take advantage of the newly defined secondary Packet zone. - netstat(1) and systat(1) quickly hacked up to do basic stat reporting but additional stats work needs to be done once some other details within UMA have been taken care of and it becomes clearer to how stats will work within the modified framework. From the user perspective, one implication is that the NMBCLUSTERS compile-time option is no longer used. The maximum number of clusters is still capped off according to maxusers, but it can be made unlimited by setting the kern.ipc.nmbclusters boot-time tunable to zero. Work should be done to write an appropriate sysctl handler allowing dynamic tuning of kern.ipc.nmbclusters at runtime. Additional things worth noting/known issues (READ): - One report of 'ips' (ServeRAID) driver acting really slow in conjunction with mbuma. Need more data. Latest report is that ips is equally sucking with and without mbuma. - Giant leak in NFS code sometimes occurs, can't reproduce but currently analyzing; brueffer is able to reproduce but THIS IS NOT an mbuma-specific problem and currently occurs even WITHOUT mbuma. - Issues in network locking: there is at least one code path in the rip code where one or more locks are acquired and we end up in m_prepend() with M_WAITOK, which causes WITNESS to whine from within UMA. Current temporary solution: force all UMA allocations to be M_NOWAIT from within UMA for now to avoid deadlocks unless WITNESS is defined and we can determine with certainty that we're not holding any locks when we're M_WAITOK. - I've seen at least one weird socketbuffer empty-but- mbuf-still-attached panic. I don't believe this to be related to mbuma but please keep your eyes open, turn on debugging, and capture crash dumps. This change removes more code than it adds. A paper is available detailing the change and considering various performance issues, it was presented at BSDCan2004: http://www.unixdaemons.com/~bmilekic/netbuf_bmilekic.pdf Please read the paper for Future Work and implementation details, as well as credits. Testing and Debugging: rwatson, brueffer, Ketrien I. Saihr-Kesenchedra, ... Reviewed by: Lots of people (for different parts)
2004-05-31 21:46:06 +00:00
uma_zfree_arg(LIST_FIRST(&slab->us_keg->uk_zones), addr, slab);
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
} else {
size = slab->us_size;
uma_large_free(slab);
Add sufficient braces to keep egcs happy about potentially ambiguous if/else nesting.
1999-05-06 18:13:11 +00:00
}
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
malloc_type_freed(mtp, size);
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
}
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
/*
* realloc: change the size of a memory block
*/
void *
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
realloc(void *addr, unsigned long size, struct malloc_type *mtp, int flags)
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
{
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
uma_slab_t slab;
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
unsigned long alloc;
void *newaddr;
struct malloc_type has had a 'magic' field statically initialized to M_MAGIC by MALLOC_DEFINE() for a long time; add assertions that malloc_type's passed to malloc(), free(), etc have that magic set. MFC after: 2 weeks
2009-04-19 12:41:37 +00:00
KASSERT(mtp->ks_magic == M_MAGIC,
("realloc: bad malloc type magic"));
Don't make assertions about td_critnest when the scheduler is stopped. A panicking thread always executes with a critical section held, so any attempt to allocate or free memory while dumping will otherwise cause a second panic. This can occur, for example, if xpt_polled_action() completes non-dump I/O that was pending at the time of the panic. The fact that this can occur is itself a bug, but asserting in this case does little but reduce the reliability of kernel dumps. Suggested by: kib Reported by: pho
2015-12-11 20:05:07 +00:00
KASSERT(curthread->td_critnest == 0 || SCHEDULER_STOPPED(),
Consistently enforce the restriction against calling malloc/free when in a critical section. uma_zalloc_arg()/uma_zalloc_free() may acquire a sleepable lock on the zone. The malloc() family of functions may call uma_zalloc_arg() or uma_zalloc_free(). The malloc(9) man page currently claims that free() will never sleep. It also implies that the malloc() family of functions will not sleep when called with M_NOWAIT. However, it is more correct to say that these functions will not sleep indefinitely. Indeed, they may acquire a sleepable lock. However, a developer may overlook this restriction because the WITNESS check that catches attempts to call the malloc() family of functions within a critical section is inconsistenly applied. This change clarifies the language of the malloc(9) man page to clarify the restriction against calling the malloc() family of functions while in a critical section or holding a spin lock. It also adds KASSERTs at appropriate points to make the enforcement of this restriction more consistent. PR: 204633 Differential Revision: https://reviews.freebsd.org/D4197 Reviewed by: markj Approved by: gnn (mentor) Sponsored by: Juniper Networks
2015-11-19 14:04:53 +00:00
("realloc: called with spinlock or critical section held"));
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
/* realloc(NULL, ...) is equivalent to malloc(...) */
if (addr == NULL)
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
return (malloc(size, mtp, flags));
/*
* XXX: Should report free of old memory and alloc of new memory to
* per-CPU stats.
*/
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
Bring in MemGuard, a very simple and small replacement allocator designed to help detect tamper-after-free scenarios, a problem more and more common and likely with multithreaded kernels where race conditions are more prevalent. Currently MemGuard can only take over malloc()/realloc()/free() for particular (a) malloc type(s) and the code brought in with this change manually instruments it to take over M_SUBPROC allocations as an example. If you are planning to use it, for now you must: 1) Put "options DEBUG_MEMGUARD" in your kernel config. 2) Edit src/sys/kern/kern_malloc.c manually, look for "XXX CHANGEME" and replace the M_SUBPROC comparison with the appropriate malloc type (this might require additional but small/simple code modification if, say, the malloc type is declared out of scope). 3) Build and install your kernel. Tune vm.memguard_divisor boot-time tunable which is used to scale how much of kmem_map you want to allott for MemGuard's use. The default is 10, so kmem_size/10. ToDo: 1) Bring in a memguard(9) man page. 2) Better instrumentation (e.g., boot-time) of MemGuard taking over malloc types. 3) Teach UMA about MemGuard to allow MemGuard to override zone allocations too. 4) Improve MemGuard if necessary. This work is partly based on some old patches from Ian Dowse.
2005-01-21 18:09:17 +00:00
#ifdef DEBUG_MEMGUARD
The realloc case for memguard(9) will copy too many bytes when reallocating to a smaller-sized allocation. Fix this issue. Noticed by: alc Reviewed by: alc Approved by: zml (mentor) MFC after: 3 weeks
2010-08-31 16:57:58 +00:00
if (is_memguard_addr(addr))
return (memguard_realloc(addr, size, mtp, flags));
Bring in MemGuard, a very simple and small replacement allocator designed to help detect tamper-after-free scenarios, a problem more and more common and likely with multithreaded kernels where race conditions are more prevalent. Currently MemGuard can only take over malloc()/realloc()/free() for particular (a) malloc type(s) and the code brought in with this change manually instruments it to take over M_SUBPROC allocations as an example. If you are planning to use it, for now you must: 1) Put "options DEBUG_MEMGUARD" in your kernel config. 2) Edit src/sys/kern/kern_malloc.c manually, look for "XXX CHANGEME" and replace the M_SUBPROC comparison with the appropriate malloc type (this might require additional but small/simple code modification if, say, the malloc type is declared out of scope). 3) Build and install your kernel. Tune vm.memguard_divisor boot-time tunable which is used to scale how much of kmem_map you want to allott for MemGuard's use. The default is 10, so kmem_size/10. ToDo: 1) Bring in a memguard(9) man page. 2) Better instrumentation (e.g., boot-time) of MemGuard taking over malloc types. 3) Teach UMA about MemGuard to allow MemGuard to override zone allocations too. 4) Improve MemGuard if necessary. This work is partly based on some old patches from Ian Dowse.
2005-01-21 18:09:17 +00:00
#endif
Add buffer corruption protection (RedZone) for kernel's malloc(9). It detects both: buffer underflows and buffer overflows bugs at runtime (on free(9) and realloc(9)) and prints backtraces from where memory was allocated and from where it was freed. Tested by: kris
2006-01-31 11:09:21 +00:00
#ifdef DEBUG_REDZONE
slab = NULL;
alloc = redzone_get_size(addr);
#else
- Split UMA_ZFLAG_OFFPAGE into UMA_ZFLAG_OFFPAGE and UMA_ZFLAG_HASH. - Remove all instances of the mallochash. - Stash the slab pointer in the vm page's object pointer when allocating from the kmem_obj. - Use the overloaded object pointer to find slabs for malloced memory.
2002-09-18 08:26:30 +00:00
slab = vtoslab((vm_offset_t)addr & ~(UMA_SLAB_MASK));
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
/* Sanity check */
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
KASSERT(slab != NULL,
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
("realloc: address %p out of range", (void *)addr));
/* Get the size of the original block */
In realloc(9), determine size of the original block based on UMA_SLAB_MALLOC flag. In some circumstances (I observed it when I was doing a lot of reallocs) UMA_SLAB_MALLOC can be set even if us_keg != NULL. If this is the case we have wonderful, silent data corruption, because less data is copied to the newly allocated region than should be. I'm not sure when this bug was introduced, it could be there undetected for years now, as we don't have a lot of realloc(9) consumers and it was hard to reproduce it... ...but what I know for sure, is that I don't want to know who introduce the bug:) It took me two/three days to track it down (of course most of the time I was looking for the bug in my own code).
2005-12-28 01:53:13 +00:00
if (!(slab->us_flags & UMA_SLAB_MALLOC))
Bring in mbuma to replace mballoc. mbuma is an Mbuf & Cluster allocator built on top of a number of extensions to the UMA framework, all included herein. Extensions to UMA worth noting: - Better layering between slab <-> zone caches; introduce Keg structure which splits off slab cache away from the zone structure and allows multiple zones to be stacked on top of a single Keg (single type of slab cache); perhaps we should look into defining a subset API on top of the Keg for special use by malloc(9), for example. - UMA_ZONE_REFCNT zones can now be added, and reference counters automagically allocated for them within the end of the associated slab structures. uma_find_refcnt() does a kextract to fetch the slab struct reference from the underlying page, and lookup the corresponding refcnt. mbuma things worth noting: - integrates mbuf & cluster allocations with extended UMA and provides caches for commonly-allocated items; defines several zones (two primary, one secondary) and two kegs. - change up certain code paths that always used to do: m_get() + m_clget() to instead just use m_getcl() and try to take advantage of the newly defined secondary Packet zone. - netstat(1) and systat(1) quickly hacked up to do basic stat reporting but additional stats work needs to be done once some other details within UMA have been taken care of and it becomes clearer to how stats will work within the modified framework. From the user perspective, one implication is that the NMBCLUSTERS compile-time option is no longer used. The maximum number of clusters is still capped off according to maxusers, but it can be made unlimited by setting the kern.ipc.nmbclusters boot-time tunable to zero. Work should be done to write an appropriate sysctl handler allowing dynamic tuning of kern.ipc.nmbclusters at runtime. Additional things worth noting/known issues (READ): - One report of 'ips' (ServeRAID) driver acting really slow in conjunction with mbuma. Need more data. Latest report is that ips is equally sucking with and without mbuma. - Giant leak in NFS code sometimes occurs, can't reproduce but currently analyzing; brueffer is able to reproduce but THIS IS NOT an mbuma-specific problem and currently occurs even WITHOUT mbuma. - Issues in network locking: there is at least one code path in the rip code where one or more locks are acquired and we end up in m_prepend() with M_WAITOK, which causes WITNESS to whine from within UMA. Current temporary solution: force all UMA allocations to be M_NOWAIT from within UMA for now to avoid deadlocks unless WITNESS is defined and we can determine with certainty that we're not holding any locks when we're M_WAITOK. - I've seen at least one weird socketbuffer empty-but- mbuf-still-attached panic. I don't believe this to be related to mbuma but please keep your eyes open, turn on debugging, and capture crash dumps. This change removes more code than it adds. A paper is available detailing the change and considering various performance issues, it was presented at BSDCan2004: http://www.unixdaemons.com/~bmilekic/netbuf_bmilekic.pdf Please read the paper for Future Work and implementation details, as well as credits. Testing and Debugging: rwatson, brueffer, Ketrien I. Saihr-Kesenchedra, ... Reviewed by: Lots of people (for different parts)
2004-05-31 21:46:06 +00:00
alloc = slab->us_keg->uk_size;
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
else
alloc = slab->us_size;
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
/* Reuse the original block if appropriate */
if (size <= alloc
&& (size > (alloc >> REALLOC_FRACTION) || alloc == MINALLOCSIZE))
return (addr);
Add buffer corruption protection (RedZone) for kernel's malloc(9). It detects both: buffer underflows and buffer overflows bugs at runtime (on free(9) and realloc(9)) and prints backtraces from where memory was allocated and from where it was freed. Tested by: kris
2006-01-31 11:09:21 +00:00
#endif /* !DEBUG_REDZONE */
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
/* Allocate a new, bigger (or smaller) block */
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
if ((newaddr = malloc(size, mtp, flags)) == NULL)
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
return (NULL);
/* Copy over original contents */
bcopy(addr, newaddr, min(size, alloc));
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
free(addr, mtp);
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
return (newaddr);
}
/*
* reallocf: same as realloc() but free memory on failure.
*/
void *
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
reallocf(void *addr, unsigned long size, struct malloc_type *mtp, int flags)
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
{
void *mem;
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
if ((mem = realloc(addr, size, mtp, flags)) == NULL)
free(addr, mtp);
Add realloc() and reallocf(), and make free(NULL, ...) acceptable. Reviewed by: alfred
2002-03-13 01:42:33 +00:00
return (mem);
}
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
/*
The vmem callback to reclaim kmem arena address space on low or fragmented conditions currently just wakes up the pagedaemon. The kmem arena is significantly smaller then the total available physical memory, which means that there are loads where kmem arena space could be exhausted, while there is a lot of pages available still. The woken up pagedaemon sees vm_pages_needed != 0, verifies the condition vm_paging_needed() which is false, clears the pass and returns back to sleep, not calling neither uma_reclaim() nor lowmem handler. To handle low kmem arena conditions, create additional pagedaemon thread which calls uma_reclaim() directly. The thread sleeps on the dedicated channel and kmem_reclaim() wakes the thread in addition to the pagedaemon. Reported and tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 2 weeks
2015-05-09 20:08:36 +00:00
* Wake the uma reclamation pagedaemon thread when we exhaust KVA. It
* will call the lowmem handler and uma_reclaim() callbacks in a
* context that is safe.
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
*/
Reviewed by: julian with quick glances by bruce and others Submitted by: terry (terry lambert) This is a composite of 3 patch sets submitted by terry. they are: New low-level init code that supports loadbal modules better some cleanups in the namei code to help terry in 16-bit character support some changes to the mount-root code to make it a little more modular.. NOTE: mounting root off cdrom or NFS MIGHT be broken as I haven't been able to test those cases.. certainly mounting root of disk still works just fine.. mfs should work but is untested. (tomorrows task) The low level init stuff includes a total rewrite of init_main.c to make it possible for new modules to have an init phase by simply adding an entry to a TEXT_SET (or is it DATA_SET) list. thus a new module can be added to the kernel without editing any other files other than the 'files' file.
1995-08-28 09:19:25 +00:00
static void
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
kmem_reclaim(vmem_t *vm, int flags)
{
The vmem callback to reclaim kmem arena address space on low or fragmented conditions currently just wakes up the pagedaemon. The kmem arena is significantly smaller then the total available physical memory, which means that there are loads where kmem arena space could be exhausted, while there is a lot of pages available still. The woken up pagedaemon sees vm_pages_needed != 0, verifies the condition vm_paging_needed() which is false, clears the pass and returns back to sleep, not calling neither uma_reclaim() nor lowmem handler. To handle low kmem arena conditions, create additional pagedaemon thread which calls uma_reclaim() directly. The thread sleeps on the dedicated channel and kmem_reclaim() wakes the thread in addition to the pagedaemon. Reported and tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 2 weeks
2015-05-09 20:08:36 +00:00
uma_reclaim_wakeup();
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
pagedaemon_wakeup();
}
On sparc64, VM_KMEM_SIZE_SCALE is not a constant expression, so it cannot be tested in a CTASSERT().
2014-02-23 17:37:24 +00:00
#ifndef __sparc64__
As of r257209, all architectures have defined VM_KMEM_SIZE_SCALE. In other words, every architecture is now auto-sizing the kmem arena. This revision changes kmeminit() so that the definition of VM_KMEM_SIZE_SCALE becomes mandatory and the definition of VM_KMEM_SIZE becomes optional. Replace or eliminate all existing definitions of VM_KMEM_SIZE. With auto-sizing enabled, VM_KMEM_SIZE effectively became an alternate spelling for VM_KMEM_SIZE_MIN on most architectures. Use VM_KMEM_SIZE_MIN for clarity. Change kmeminit() so that the effect of defining VM_KMEM_SIZE is similar to that of setting the tunable vm.kmem_size. Whereas the macros VM_KMEM_SIZE_{MAX,MIN,SCALE} have had the same effect as the tunables vm.kmem_size_{max,min,scale}, the effects of VM_KMEM_SIZE and vm.kmem_size have been distinct. In particular, whereas VM_KMEM_SIZE was overridden by VM_KMEM_SIZE_{MAX,MIN,SCALE} and vm.kmem_size_{max,min,scale}, vm.kmem_size was not. Remedy this inconsistency. Now, VM_KMEM_SIZE can be used to set the size of the kmem arena at compile-time without that value being overridden by auto-sizing. Update the nearby comments to reflect the kmem submap being replaced by the kmem arena. Stop duplicating the auto-sizing formula in every machine- dependent vmparam.h and place it in kmeminit() where auto-sizing takes place. Reviewed by: kib (an earlier version) Sponsored by: EMC / Isilon Storage Division
2013-11-08 16:25:00 +00:00
CTASSERT(VM_KMEM_SIZE_SCALE >= 1);
On sparc64, VM_KMEM_SIZE_SCALE is not a constant expression, so it cannot be tested in a CTASSERT().
2014-02-23 17:37:24 +00:00
#endif
As of r257209, all architectures have defined VM_KMEM_SIZE_SCALE. In other words, every architecture is now auto-sizing the kmem arena. This revision changes kmeminit() so that the definition of VM_KMEM_SIZE_SCALE becomes mandatory and the definition of VM_KMEM_SIZE becomes optional. Replace or eliminate all existing definitions of VM_KMEM_SIZE. With auto-sizing enabled, VM_KMEM_SIZE effectively became an alternate spelling for VM_KMEM_SIZE_MIN on most architectures. Use VM_KMEM_SIZE_MIN for clarity. Change kmeminit() so that the effect of defining VM_KMEM_SIZE is similar to that of setting the tunable vm.kmem_size. Whereas the macros VM_KMEM_SIZE_{MAX,MIN,SCALE} have had the same effect as the tunables vm.kmem_size_{max,min,scale}, the effects of VM_KMEM_SIZE and vm.kmem_size have been distinct. In particular, whereas VM_KMEM_SIZE was overridden by VM_KMEM_SIZE_{MAX,MIN,SCALE} and vm.kmem_size_{max,min,scale}, vm.kmem_size was not. Remedy this inconsistency. Now, VM_KMEM_SIZE can be used to set the size of the kmem arena at compile-time without that value being overridden by auto-sizing. Update the nearby comments to reflect the kmem submap being replaced by the kmem arena. Stop duplicating the auto-sizing formula in every machine- dependent vmparam.h and place it in kmeminit() where auto-sizing takes place. Reviewed by: kib (an earlier version) Sponsored by: EMC / Isilon Storage Division
2013-11-08 16:25:00 +00:00
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
/*
As of r257209, all architectures have defined VM_KMEM_SIZE_SCALE. In other words, every architecture is now auto-sizing the kmem arena. This revision changes kmeminit() so that the definition of VM_KMEM_SIZE_SCALE becomes mandatory and the definition of VM_KMEM_SIZE becomes optional. Replace or eliminate all existing definitions of VM_KMEM_SIZE. With auto-sizing enabled, VM_KMEM_SIZE effectively became an alternate spelling for VM_KMEM_SIZE_MIN on most architectures. Use VM_KMEM_SIZE_MIN for clarity. Change kmeminit() so that the effect of defining VM_KMEM_SIZE is similar to that of setting the tunable vm.kmem_size. Whereas the macros VM_KMEM_SIZE_{MAX,MIN,SCALE} have had the same effect as the tunables vm.kmem_size_{max,min,scale}, the effects of VM_KMEM_SIZE and vm.kmem_size have been distinct. In particular, whereas VM_KMEM_SIZE was overridden by VM_KMEM_SIZE_{MAX,MIN,SCALE} and vm.kmem_size_{max,min,scale}, vm.kmem_size was not. Remedy this inconsistency. Now, VM_KMEM_SIZE can be used to set the size of the kmem arena at compile-time without that value being overridden by auto-sizing. Update the nearby comments to reflect the kmem submap being replaced by the kmem arena. Stop duplicating the auto-sizing formula in every machine- dependent vmparam.h and place it in kmeminit() where auto-sizing takes place. Reviewed by: kib (an earlier version) Sponsored by: EMC / Isilon Storage Division
2013-11-08 16:25:00 +00:00
* Initialize the kernel memory (kmem) arena.
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
*/
void
kmeminit(void)
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
{
Pull in r267961 and r267973 again. Fix for issues reported will follow.
2014-06-28 03:56:17 +00:00
u_long mem_size;
u_long tmp;
As of r257209, all architectures have defined VM_KMEM_SIZE_SCALE. In other words, every architecture is now auto-sizing the kmem arena. This revision changes kmeminit() so that the definition of VM_KMEM_SIZE_SCALE becomes mandatory and the definition of VM_KMEM_SIZE becomes optional. Replace or eliminate all existing definitions of VM_KMEM_SIZE. With auto-sizing enabled, VM_KMEM_SIZE effectively became an alternate spelling for VM_KMEM_SIZE_MIN on most architectures. Use VM_KMEM_SIZE_MIN for clarity. Change kmeminit() so that the effect of defining VM_KMEM_SIZE is similar to that of setting the tunable vm.kmem_size. Whereas the macros VM_KMEM_SIZE_{MAX,MIN,SCALE} have had the same effect as the tunables vm.kmem_size_{max,min,scale}, the effects of VM_KMEM_SIZE and vm.kmem_size have been distinct. In particular, whereas VM_KMEM_SIZE was overridden by VM_KMEM_SIZE_{MAX,MIN,SCALE} and vm.kmem_size_{max,min,scale}, vm.kmem_size was not. Remedy this inconsistency. Now, VM_KMEM_SIZE can be used to set the size of the kmem arena at compile-time without that value being overridden by auto-sizing. Update the nearby comments to reflect the kmem submap being replaced by the kmem arena. Stop duplicating the auto-sizing formula in every machine- dependent vmparam.h and place it in kmeminit() where auto-sizing takes place. Reviewed by: kib (an earlier version) Sponsored by: EMC / Isilon Storage Division
2013-11-08 16:25:00 +00:00
Pull in r267961 and r267973 again. Fix for issues reported will follow.
2014-06-28 03:56:17 +00:00
#ifdef VM_KMEM_SIZE
if (vm_kmem_size == 0)
vm_kmem_size = VM_KMEM_SIZE;
#endif
#ifdef VM_KMEM_SIZE_MIN
if (vm_kmem_size_min == 0)
vm_kmem_size_min = VM_KMEM_SIZE_MIN;
#endif
#ifdef VM_KMEM_SIZE_MAX
if (vm_kmem_size_max == 0)
vm_kmem_size_max = VM_KMEM_SIZE_MAX;
#endif
Try to dynamically size the VM_KMEM_SIZE (but is still able to be overridden in a way identically as before.) I had problems with the system properly handling the number of vnodes when there is alot of system memory, and the default VM_KMEM_SIZE. Two new options "VM_KMEM_SIZE_SCALE" and "VM_KMEM_SIZE_MAX" have been added to support better auto-sizing for systems with greater than 128MB.
1998-02-23 07:41:23 +00:00
/*
As of r257209, all architectures have defined VM_KMEM_SIZE_SCALE. In other words, every architecture is now auto-sizing the kmem arena. This revision changes kmeminit() so that the definition of VM_KMEM_SIZE_SCALE becomes mandatory and the definition of VM_KMEM_SIZE becomes optional. Replace or eliminate all existing definitions of VM_KMEM_SIZE. With auto-sizing enabled, VM_KMEM_SIZE effectively became an alternate spelling for VM_KMEM_SIZE_MIN on most architectures. Use VM_KMEM_SIZE_MIN for clarity. Change kmeminit() so that the effect of defining VM_KMEM_SIZE is similar to that of setting the tunable vm.kmem_size. Whereas the macros VM_KMEM_SIZE_{MAX,MIN,SCALE} have had the same effect as the tunables vm.kmem_size_{max,min,scale}, the effects of VM_KMEM_SIZE and vm.kmem_size have been distinct. In particular, whereas VM_KMEM_SIZE was overridden by VM_KMEM_SIZE_{MAX,MIN,SCALE} and vm.kmem_size_{max,min,scale}, vm.kmem_size was not. Remedy this inconsistency. Now, VM_KMEM_SIZE can be used to set the size of the kmem arena at compile-time without that value being overridden by auto-sizing. Update the nearby comments to reflect the kmem submap being replaced by the kmem arena. Stop duplicating the auto-sizing formula in every machine- dependent vmparam.h and place it in kmeminit() where auto-sizing takes place. Reviewed by: kib (an earlier version) Sponsored by: EMC / Isilon Storage Division
2013-11-08 16:25:00 +00:00
* Calculate the amount of kernel virtual address (KVA) space that is
* preallocated to the kmem arena. In order to support a wide range
* of machines, it is a function of the physical memory size,
* specifically,
*
* min(max(physical memory size / VM_KMEM_SIZE_SCALE,
* VM_KMEM_SIZE_MIN), VM_KMEM_SIZE_MAX)
Try to dynamically size the VM_KMEM_SIZE (but is still able to be overridden in a way identically as before.) I had problems with the system properly handling the number of vnodes when there is alot of system memory, and the default VM_KMEM_SIZE. Two new options "VM_KMEM_SIZE_SCALE" and "VM_KMEM_SIZE_MAX" have been added to support better auto-sizing for systems with greater than 128MB.
1998-02-23 07:41:23 +00:00
*
As of r257209, all architectures have defined VM_KMEM_SIZE_SCALE. In other words, every architecture is now auto-sizing the kmem arena. This revision changes kmeminit() so that the definition of VM_KMEM_SIZE_SCALE becomes mandatory and the definition of VM_KMEM_SIZE becomes optional. Replace or eliminate all existing definitions of VM_KMEM_SIZE. With auto-sizing enabled, VM_KMEM_SIZE effectively became an alternate spelling for VM_KMEM_SIZE_MIN on most architectures. Use VM_KMEM_SIZE_MIN for clarity. Change kmeminit() so that the effect of defining VM_KMEM_SIZE is similar to that of setting the tunable vm.kmem_size. Whereas the macros VM_KMEM_SIZE_{MAX,MIN,SCALE} have had the same effect as the tunables vm.kmem_size_{max,min,scale}, the effects of VM_KMEM_SIZE and vm.kmem_size have been distinct. In particular, whereas VM_KMEM_SIZE was overridden by VM_KMEM_SIZE_{MAX,MIN,SCALE} and vm.kmem_size_{max,min,scale}, vm.kmem_size was not. Remedy this inconsistency. Now, VM_KMEM_SIZE can be used to set the size of the kmem arena at compile-time without that value being overridden by auto-sizing. Update the nearby comments to reflect the kmem submap being replaced by the kmem arena. Stop duplicating the auto-sizing formula in every machine- dependent vmparam.h and place it in kmeminit() where auto-sizing takes place. Reviewed by: kib (an earlier version) Sponsored by: EMC / Isilon Storage Division
2013-11-08 16:25:00 +00:00
* Every architecture must define an integral value for
* VM_KMEM_SIZE_SCALE. However, the definitions of VM_KMEM_SIZE_MIN
* and VM_KMEM_SIZE_MAX, which represent respectively the floor and
* ceiling on this preallocation, are optional. Typically,
* VM_KMEM_SIZE_MAX is itself a function of the available KVA space on
* a given architecture.
Try to dynamically size the VM_KMEM_SIZE (but is still able to be overridden in a way identically as before.) I had problems with the system properly handling the number of vnodes when there is alot of system memory, and the default VM_KMEM_SIZE. Two new options "VM_KMEM_SIZE_SCALE" and "VM_KMEM_SIZE_MAX" have been added to support better auto-sizing for systems with greater than 128MB.
1998-02-23 07:41:23 +00:00
*/
Rename global cnt to vm_cnt to avoid shadowing. To reduce the diff struct pcu.cnt field was not renamed, so PCPU_OP(cnt.field) is still used. pc_cnt and pcpu are also used in kvm(3) and vmstat(8). The goal was to not affect externally used KPI. Bump __FreeBSD_version_ in case some out-of-tree module/code relies on the the global cnt variable. Exp-run revealed no ports using it directly. No objection from: arch@ Sponsored by: EMC / Isilon Storage Division
2014-03-22 10:26:09 +00:00
mem_size = vm_cnt.v_page_count;
svn revisions r269964 and r269963 seemed to have impaired small memory footprint systems(32M/64M) and didn't leave enough free memory to load modules when it was setting up page tables that for sizes that are never used on these smallish boards. Set kmem_zmax to PAGE_SIZE on these smaller systems (< 128M) to keep this from happening. Verified on mips32 h/w. PR: 193465 Submitted by: delphij Reviewed by: adrian
2014-09-22 05:07:22 +00:00
if (mem_size <= 32768) /* delphij XXX 128MB */
kmem_zmax = PAGE_SIZE;
Try to dynamically size the VM_KMEM_SIZE (but is still able to be overridden in a way identically as before.) I had problems with the system properly handling the number of vnodes when there is alot of system memory, and the default VM_KMEM_SIZE. Two new options "VM_KMEM_SIZE_SCALE" and "VM_KMEM_SIZE_MAX" have been added to support better auto-sizing for systems with greater than 128MB.
1998-02-23 07:41:23 +00:00
As of r257209, all architectures have defined VM_KMEM_SIZE_SCALE. In other words, every architecture is now auto-sizing the kmem arena. This revision changes kmeminit() so that the definition of VM_KMEM_SIZE_SCALE becomes mandatory and the definition of VM_KMEM_SIZE becomes optional. Replace or eliminate all existing definitions of VM_KMEM_SIZE. With auto-sizing enabled, VM_KMEM_SIZE effectively became an alternate spelling for VM_KMEM_SIZE_MIN on most architectures. Use VM_KMEM_SIZE_MIN for clarity. Change kmeminit() so that the effect of defining VM_KMEM_SIZE is similar to that of setting the tunable vm.kmem_size. Whereas the macros VM_KMEM_SIZE_{MAX,MIN,SCALE} have had the same effect as the tunables vm.kmem_size_{max,min,scale}, the effects of VM_KMEM_SIZE and vm.kmem_size have been distinct. In particular, whereas VM_KMEM_SIZE was overridden by VM_KMEM_SIZE_{MAX,MIN,SCALE} and vm.kmem_size_{max,min,scale}, vm.kmem_size was not. Remedy this inconsistency. Now, VM_KMEM_SIZE can be used to set the size of the kmem arena at compile-time without that value being overridden by auto-sizing. Update the nearby comments to reflect the kmem submap being replaced by the kmem arena. Stop duplicating the auto-sizing formula in every machine- dependent vmparam.h and place it in kmeminit() where auto-sizing takes place. Reviewed by: kib (an earlier version) Sponsored by: EMC / Isilon Storage Division
2013-11-08 16:25:00 +00:00
if (vm_kmem_size_scale < 1)
vm_kmem_size_scale = VM_KMEM_SIZE_SCALE;
Pull in r267961 and r267973 again. Fix for issues reported will follow.
2014-06-28 03:56:17 +00:00
/*
* Check if we should use defaults for the "vm_kmem_size"
* variable:
*/
if (vm_kmem_size == 0) {
vm_kmem_size = (mem_size / vm_kmem_size_scale) * PAGE_SIZE;
Revert r267961, r267973: These changes prevent sysctl(8) from returning proper output, such as: 1) no output from sysctl(8) 2) erroneously returning ENOMEM with tools like truss(1) or uname(1) truss: can not get etype: Cannot allocate memory
2014-06-27 22:05:21 +00:00
Pull in r267961 and r267973 again. Fix for issues reported will follow.
2014-06-28 03:56:17 +00:00
if (vm_kmem_size_min > 0 && vm_kmem_size < vm_kmem_size_min)
vm_kmem_size = vm_kmem_size_min;
if (vm_kmem_size_max > 0 && vm_kmem_size >= vm_kmem_size_max)
vm_kmem_size = vm_kmem_size_max;
}
Try to dynamically size the VM_KMEM_SIZE (but is still able to be overridden in a way identically as before.) I had problems with the system properly handling the number of vnodes when there is alot of system memory, and the default VM_KMEM_SIZE. Two new options "VM_KMEM_SIZE_SCALE" and "VM_KMEM_SIZE_MAX" have been added to support better auto-sizing for systems with greater than 128MB.
1998-02-23 07:41:23 +00:00
Fixed sign and overflow bugs that caused the allocation size of the kernel malloc region (kmem_map) to be wrong and semi-random on systems with more than 1GB of RAM. This is not a complete fix, but is sufficient for machines with 4GB or less of memory. A complete fix will require some changes to the getenv stuff so that 64bit values can be passed around. NOT FIXED: machines with more than 4GB of RAM (e.g. some large Alphas) since we're still using ints to hold some of the values. Reviewed by: bde
2000-01-28 04:04:58 +00:00
/*
Pull in r267961 and r267973 again. Fix for issues reported will follow.
2014-06-28 03:56:17 +00:00
* The amount of KVA space that is preallocated to the
As of r257209, all architectures have defined VM_KMEM_SIZE_SCALE. In other words, every architecture is now auto-sizing the kmem arena. This revision changes kmeminit() so that the definition of VM_KMEM_SIZE_SCALE becomes mandatory and the definition of VM_KMEM_SIZE becomes optional. Replace or eliminate all existing definitions of VM_KMEM_SIZE. With auto-sizing enabled, VM_KMEM_SIZE effectively became an alternate spelling for VM_KMEM_SIZE_MIN on most architectures. Use VM_KMEM_SIZE_MIN for clarity. Change kmeminit() so that the effect of defining VM_KMEM_SIZE is similar to that of setting the tunable vm.kmem_size. Whereas the macros VM_KMEM_SIZE_{MAX,MIN,SCALE} have had the same effect as the tunables vm.kmem_size_{max,min,scale}, the effects of VM_KMEM_SIZE and vm.kmem_size have been distinct. In particular, whereas VM_KMEM_SIZE was overridden by VM_KMEM_SIZE_{MAX,MIN,SCALE} and vm.kmem_size_{max,min,scale}, vm.kmem_size was not. Remedy this inconsistency. Now, VM_KMEM_SIZE can be used to set the size of the kmem arena at compile-time without that value being overridden by auto-sizing. Update the nearby comments to reflect the kmem submap being replaced by the kmem arena. Stop duplicating the auto-sizing formula in every machine- dependent vmparam.h and place it in kmeminit() where auto-sizing takes place. Reviewed by: kib (an earlier version) Sponsored by: EMC / Isilon Storage Division
2013-11-08 16:25:00 +00:00
* kmem arena can be set statically at compile-time or manually
* through the kernel environment. However, it is still limited to
* twice the physical memory size, which has been sufficient to handle
* the most severe cases of external fragmentation in the kmem arena.
Fixed sign and overflow bugs that caused the allocation size of the kernel malloc region (kmem_map) to be wrong and semi-random on systems with more than 1GB of RAM. This is not a complete fix, but is sufficient for machines with 4GB or less of memory. A complete fix will require some changes to the getenv stuff so that 64bit values can be passed around. NOT FIXED: machines with more than 4GB of RAM (e.g. some large Alphas) since we're still using ints to hold some of the values. Reviewed by: bde
2000-01-28 04:04:58 +00:00
*/
Eliminate the possibility of 32-bit arithmetic overflow in the calculation of vm_kmem_size that may occur if the system administrator has specified a vm.vm_kmem_size tunable value that exceeds the hard cap. PR: 162741 Submitted by: Adam McDougall Reviewed by: bde@ MFC after: 3 weeks
2011-12-07 07:03:14 +00:00
if (vm_kmem_size / 2 / PAGE_SIZE > mem_size)
vm_kmem_size = 2 * mem_size * PAGE_SIZE;
Try to dynamically size the VM_KMEM_SIZE (but is still able to be overridden in a way identically as before.) I had problems with the system properly handling the number of vnodes when there is alot of system memory, and the default VM_KMEM_SIZE. Two new options "VM_KMEM_SIZE_SCALE" and "VM_KMEM_SIZE_MAX" have been added to support better auto-sizing for systems with greater than 128MB.
1998-02-23 07:41:23 +00:00
Instead of just trying to do it for arm, make sure vm_kmem_size is properly aligned in kmeminit(), where it'll work for any arch. Suggested by: alc
2013-08-09 22:30:54 +00:00
vm_kmem_size = round_page(vm_kmem_size);
Rework memguard(9) to reserve significantly more KVA to detect use-after-free over a longer time. Also release the backing pages of a guarded allocation at free(9) time to reduce the overhead of using memguard(9). Allow setting and varying the malloc type at run-time. Add knobs to allow: - randomly guarding memory - adding un-backed KVA guard pages to detect underflow and overflow - a lower limit on the size of allocations that are guarded Reviewed by: alc Reviewed by: brueffer, Ulrich Spörlein <uqs spoerlein net> (man page) Silence from: -arch Approved by: zml (mentor) MFC after: 1 month
2010-08-11 22:10:37 +00:00
#ifdef DEBUG_MEMGUARD
Fix a bug with memguard(9) on 32-bit architectures without a VM_KMEM_MAX_SIZE. The code was not taking into account the size of the kernel_map, which the kmem_map is allocated from, so it could produce a sub-map size too large to fit. The simplest solution is to ignore VM_KMEM_MAX entirely and base the memguard map's size off the kernel_map's size, since this is always relevant and always smaller. Found by: Justin Hibbits
2012-07-15 20:29:48 +00:00
tmp = memguard_fudge(vm_kmem_size, kernel_map);
Rework memguard(9) to reserve significantly more KVA to detect use-after-free over a longer time. Also release the backing pages of a guarded allocation at free(9) time to reduce the overhead of using memguard(9). Allow setting and varying the malloc type at run-time. Add knobs to allow: - randomly guarding memory - adding un-backed KVA guard pages to detect underflow and overflow - a lower limit on the size of allocations that are guarded Reviewed by: alc Reviewed by: brueffer, Ulrich Spörlein <uqs spoerlein net> (man page) Silence from: -arch Approved by: zml (mentor) MFC after: 1 month
2010-08-11 22:10:37 +00:00
#else
tmp = vm_kmem_size;
#endif
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
vmem_init(kmem_arena, "kmem arena", kva_alloc(tmp), tmp, PAGE_SIZE,
- Disable quantum caches on the kmem_arena. This can make fragmentation worse on small KVA systems. I had intended to only enable it for debugging. Sponsored by: EMC / Isilon Storage Division
2013-08-13 22:41:24 +00:00
0, 0);
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
vmem_set_reclaim(kmem_arena, kmem_reclaim);
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
Bring in MemGuard, a very simple and small replacement allocator designed to help detect tamper-after-free scenarios, a problem more and more common and likely with multithreaded kernels where race conditions are more prevalent. Currently MemGuard can only take over malloc()/realloc()/free() for particular (a) malloc type(s) and the code brought in with this change manually instruments it to take over M_SUBPROC allocations as an example. If you are planning to use it, for now you must: 1) Put "options DEBUG_MEMGUARD" in your kernel config. 2) Edit src/sys/kern/kern_malloc.c manually, look for "XXX CHANGEME" and replace the M_SUBPROC comparison with the appropriate malloc type (this might require additional but small/simple code modification if, say, the malloc type is declared out of scope). 3) Build and install your kernel. Tune vm.memguard_divisor boot-time tunable which is used to scale how much of kmem_map you want to allott for MemGuard's use. The default is 10, so kmem_size/10. ToDo: 1) Bring in a memguard(9) man page. 2) Better instrumentation (e.g., boot-time) of MemGuard taking over malloc types. 3) Teach UMA about MemGuard to allow MemGuard to override zone allocations too. 4) Improve MemGuard if necessary. This work is partly based on some old patches from Ian Dowse.
2005-01-21 18:09:17 +00:00
#ifdef DEBUG_MEMGUARD
/*
* Initialize MemGuard if support compiled in. MemGuard is a
* replacement allocator used for detecting tamper-after-free
* scenarios as they occur. It is only used for debugging.
*/
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
memguard_init(kmem_arena);
Bring in MemGuard, a very simple and small replacement allocator designed to help detect tamper-after-free scenarios, a problem more and more common and likely with multithreaded kernels where race conditions are more prevalent. Currently MemGuard can only take over malloc()/realloc()/free() for particular (a) malloc type(s) and the code brought in with this change manually instruments it to take over M_SUBPROC allocations as an example. If you are planning to use it, for now you must: 1) Put "options DEBUG_MEMGUARD" in your kernel config. 2) Edit src/sys/kern/kern_malloc.c manually, look for "XXX CHANGEME" and replace the M_SUBPROC comparison with the appropriate malloc type (this might require additional but small/simple code modification if, say, the malloc type is declared out of scope). 3) Build and install your kernel. Tune vm.memguard_divisor boot-time tunable which is used to scale how much of kmem_map you want to allott for MemGuard's use. The default is 10, so kmem_size/10. ToDo: 1) Bring in a memguard(9) man page. 2) Better instrumentation (e.g., boot-time) of MemGuard taking over malloc types. 3) Teach UMA about MemGuard to allow MemGuard to override zone allocations too. 4) Improve MemGuard if necessary. This work is partly based on some old patches from Ian Dowse.
2005-01-21 18:09:17 +00:00
#endif
Replace kernel virtual address space allocation with vmem. This provides transparent layering and better fragmentation. - Normalize functions that allocate memory to use kmem_* - Those that allocate address space are named kva_* - Those that operate on maps are named kmap_* - Implement recursive allocation handling for kmem_arena in vmem. Reviewed by: alc Tested by: pho Sponsored by: EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
}
/*
* Initialize the kernel memory allocator
*/
/* ARGSUSED*/
static void
mallocinit(void *dummy)
{
int i;
uint8_t indx;
mtx_init(&malloc_mtx, "malloc", NULL, MTX_DEF);
kmeminit();
Bring in MemGuard, a very simple and small replacement allocator designed to help detect tamper-after-free scenarios, a problem more and more common and likely with multithreaded kernels where race conditions are more prevalent. Currently MemGuard can only take over malloc()/realloc()/free() for particular (a) malloc type(s) and the code brought in with this change manually instruments it to take over M_SUBPROC allocations as an example. If you are planning to use it, for now you must: 1) Put "options DEBUG_MEMGUARD" in your kernel config. 2) Edit src/sys/kern/kern_malloc.c manually, look for "XXX CHANGEME" and replace the M_SUBPROC comparison with the appropriate malloc type (this might require additional but small/simple code modification if, say, the malloc type is declared out of scope). 3) Build and install your kernel. Tune vm.memguard_divisor boot-time tunable which is used to scale how much of kmem_map you want to allott for MemGuard's use. The default is 10, so kmem_size/10. ToDo: 1) Bring in a memguard(9) man page. 2) Better instrumentation (e.g., boot-time) of MemGuard taking over malloc types. 3) Teach UMA about MemGuard to allow MemGuard to override zone allocations too. 4) Improve MemGuard if necessary. This work is partly based on some old patches from Ian Dowse.
2005-01-21 18:09:17 +00:00
- Split UMA_ZFLAG_OFFPAGE into UMA_ZFLAG_OFFPAGE and UMA_ZFLAG_HASH. - Remove all instances of the mallochash. - Stash the slab pointer in the vm page's object pointer when allocating from the kmem_obj. - Use the overloaded object pointer to find slabs for malloced memory.
2002-09-18 08:26:30 +00:00
uma_startup2();
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
Add a new loader tunable, vm.kmem_zmax which allows a system administrator to limit the maximum allocation size that malloc(9) would consider using the UMA cache allocator as backend. Suggested by: alfred MFC after: 2 weeks
2014-08-14 05:31:39 +00:00
if (kmem_zmax < PAGE_SIZE || kmem_zmax > KMEM_ZMAX)
kmem_zmax = KMEM_ZMAX;
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
mt_zone = uma_zcreate("mt_zone", sizeof(struct malloc_type_internal),
#ifdef INVARIANTS
mtrash_ctor, mtrash_dtor, mtrash_init, mtrash_fini,
#else
NULL, NULL, NULL, NULL,
#endif
UMA_ALIGN_PTR, UMA_ZONE_MALLOC);
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
for (i = 0, indx = 0; kmemzones[indx].kz_size != 0; indx++) {
int size = kmemzones[indx].kz_size;
char *name = kmemzones[indx].kz_name;
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
int subzone;
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
for (subzone = 0; subzone < numzones; subzone++) {
kmemzones[indx].kz_zone[subzone] =
uma_zcreate(name, size,
Add a new UMA debugging facility. This will overwrite freed memory with 0xdeadc0de and then check for it just before memory is handed off as part of a new request. This will catch any post free/pre alloc modification of memory, as well as introduce errors for anything that tries to dereference it as a pointer. This code takes the form of special init, fini, ctor and dtor routines that are specificly used by malloc. It is in a seperate file because additional debugging aids will want to live here as well.
2002-04-30 07:54:25 +00:00
#ifdef INVARIANTS
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
mtrash_ctor, mtrash_dtor, mtrash_init, mtrash_fini,
Add a new UMA debugging facility. This will overwrite freed memory with 0xdeadc0de and then check for it just before memory is handed off as part of a new request. This will catch any post free/pre alloc modification of memory, as well as introduce errors for anything that tries to dereference it as a pointer. This code takes the form of special init, fini, ctor and dtor routines that are specificly used by malloc. It is in a seperate file because additional debugging aids will want to live here as well.
2002-04-30 07:54:25 +00:00
#else
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
NULL, NULL, NULL, NULL,
Add a new UMA debugging facility. This will overwrite freed memory with 0xdeadc0de and then check for it just before memory is handed off as part of a new request. This will catch any post free/pre alloc modification of memory, as well as introduce errors for anything that tries to dereference it as a pointer. This code takes the form of special init, fini, ctor and dtor routines that are specificly used by malloc. It is in a seperate file because additional debugging aids will want to live here as well.
2002-04-30 07:54:25 +00:00
#endif
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
UMA_ALIGN_PTR, UMA_ZONE_MALLOC);
}
This is the first part of the new kernel memory allocator. This replaces malloc(9) and vm_zone with a slab like allocator. Reviewed by: arch@
2002-03-19 09:11:49 +00:00
for (;i <= size; i+= KMEM_ZBASE)
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
kmemsize[i >> KMEM_ZSHIFT] = indx;
Add a new loader tunable, vm.kmem_zmax which allows a system administrator to limit the maximum allocation size that malloc(9) would consider using the UMA cache allocator as backend. Suggested by: alfred MFC after: 2 weeks
2014-08-14 05:31:39 +00:00
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
}
Make malloc more extensible. The malloc type is now a pointer to the struct kmemstats that describes the type. This allows subsystems to declare their malloc types locally and <sys/malloc.h> doesn't need tweaked everytime somebody gets an idea. You can even have a type local to a lkm... I don't know if we really need the longdesc, comments welcome. TODO: There is a single nit in ext2fs, that will be fixed later, and I intend to remove all unused malloc types and distribute the rest closer to their use.
1997-10-10 14:06:34 +00:00
}
Pull in r267961 and r267973 again. Fix for issues reported will follow.
2014-06-28 03:56:17 +00:00
SYSINIT(kmem, SI_SUB_KMEM, SI_ORDER_SECOND, mallocinit, NULL);
Make malloc more extensible. The malloc type is now a pointer to the struct kmemstats that describes the type. This allows subsystems to declare their malloc types locally and <sys/malloc.h> doesn't need tweaked everytime somebody gets an idea. You can even have a type local to a lkm... I don't know if we really need the longdesc, comments welcome. TODO: There is a single nit in ext2fs, that will be fixed later, and I intend to remove all unused malloc types and distribute the rest closer to their use.
1997-10-10 14:06:34 +00:00
Have MALLOC_DECLARE() initialize malloc types explicitly, and have them removed at module unload (if in a module of course). However; this introduces a new dependency on <sys/kernel.h> for things that use MALLOC_DECLARE(). Bruce told me it is better to add sys/kernel.h to the handful of files that need it rather than add an extra include to sys/malloc.h for kernel compiles. Updates to follow in subsequent commits.
1998-11-10 08:46:24 +00:00
void
Consistently style function declarations in kern_malloc.c. MFC after: 3 days
2005-04-12 23:54:34 +00:00
malloc_init(void *data)
Make malloc more extensible. The malloc type is now a pointer to the struct kmemstats that describes the type. This allows subsystems to declare their malloc types locally and <sys/malloc.h> doesn't need tweaked everytime somebody gets an idea. You can even have a type local to a lkm... I don't know if we really need the longdesc, comments welcome. TODO: There is a single nit in ext2fs, that will be fixed later, and I intend to remove all unused malloc types and distribute the rest closer to their use.
1997-10-10 14:06:34 +00:00
{
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
struct malloc_type_internal *mtip;
struct malloc_type *mtp;
Make malloc more extensible. The malloc type is now a pointer to the struct kmemstats that describes the type. This allows subsystems to declare their malloc types locally and <sys/malloc.h> doesn't need tweaked everytime somebody gets an idea. You can even have a type local to a lkm... I don't know if we really need the longdesc, comments welcome. TODO: There is a single nit in ext2fs, that will be fixed later, and I intend to remove all unused malloc types and distribute the rest closer to their use.
1997-10-10 14:06:34 +00:00
Rename global cnt to vm_cnt to avoid shadowing. To reduce the diff struct pcu.cnt field was not renamed, so PCPU_OP(cnt.field) is still used. pc_cnt and pcpu are also used in kvm(3) and vmstat(8). The goal was to not affect externally used KPI. Bump __FreeBSD_version_ in case some out-of-tree module/code relies on the the global cnt variable. Exp-run revealed no ports using it directly. No objection from: arch@ Sponsored by: EMC / Isilon Storage Division
2014-03-22 10:26:09 +00:00
KASSERT(vm_cnt.v_page_count != 0, ("malloc_register before vm_init"));
Remove the long description from the in-kernel datastructure. Put a magic field in there instead, to help catch uninitialized malloc types.
1997-10-28 19:01:02 +00:00
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
mtp = data;
If we're passed garbage in malloc_init(), panic() rather than expecting a KASSERT to handle it. People are likely to turn off INVARIANTS RSN and loading an old module can cause garbage-in here. I saw the issue with an older nvidia driver (x11/nvidia-driver) loading into a new kernel - a crash wasn't seen 'till sysctl_kern_malloc_stats(). I was lucky that mtp->ks_shortdesc was NULL and not something horrible. While I'm here, KASSERT that malloc_uninit() isn't passed something that's not in kmemstatistics. MFC after: 3 weeks
2009-06-05 09:16:52 +00:00
if (mtp->ks_magic != M_MAGIC)
panic("malloc_init: bad malloc type magic");
struct malloc_type has had a 'magic' field statically initialized to M_MAGIC by MALLOC_DEFINE() for a long time; add assertions that malloc_type's passed to malloc(), free(), etc have that magic set. MFC after: 2 weeks
2009-04-19 12:41:37 +00:00
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
mtip = uma_zalloc(mt_zone, M_WAITOK | M_ZERO);
mtp->ks_handle = mtip;
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
mtip->mti_zone = mtp_get_subzone(mtp->ks_shortdesc);
Some fixes from John Hood: 1) Fix the initialization of malloc structure that changed due to perf opt. 2) Remove unneeded include. 3) An initialization assert added to malloc. Submitted by: John Hood <cgull@smoke.marlboro.vt.us>
1997-12-05 05:36:58 +00:00
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
mtx_lock(&malloc_mtx);
mtp->ks_next = kmemstatistics;
kmemstatistics = mtp;
Introduce a new sysctl, kern.malloc_stats, which exports kernel malloc statistics via a binary structure stream: - Add structure 'malloc_type_stream_header', which defines a stream version, definition of MAXCPUS used in the stream, and a number of malloc_type records in the stream. - Add structure 'malloc_type_header', which defines the name of the malloc type being reported on. - When the sysctl is queried, return a stream header, followed by a series of type descriptions, each consisting of a type header followed by a series of MAXCPUS malloc_type_stats structures holding per-CPU allocation information. Typical values of MAXCPUS will be 1 (UP compiled kernel) and 16 (SMP compiled kernel). This query mechanism allows user space monitoring tools to extract memory allocation statistics in a machine-readable form, and to do so at a per-CPU granularity, allowing monitoring of allocation patterns across CPUs in order to better understand the distribution of work and memory flow over multiple CPUs. While here: - Bump statistics width to uint64_t, and hard code using fixed-width type in order to be more sure about structure layout in the stream. We allocate and free a lot of memory. - Add kmemcount, a counter of the number of registered malloc types, in order to avoid excessive manual counting of types. Export via a new sysctl to allow user-space code to better size buffers. - De-XXX comment on no longer maintaining the high watermark in old sysctl monitoring code. A follow-up commit of libmemstat(3), a library to monitor kernel memory allocation, will occur in the next few days. Likewise, similar changes to UMA.
2005-07-14 11:52:06 +00:00
kmemcount++;
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
mtx_unlock(&malloc_mtx);
BSD 4.4 Lite Kernel Sources
1994-05-24 10:09:53 +00:00
}
Have MALLOC_DECLARE() initialize malloc types explicitly, and have them removed at module unload (if in a module of course). However; this introduces a new dependency on <sys/kernel.h> for things that use MALLOC_DECLARE(). Bruce told me it is better to add sys/kernel.h to the handful of files that need it rather than add an extra include to sys/malloc.h for kernel compiles. Updates to follow in subsequent commits.
1998-11-10 08:46:24 +00:00
void
Consistently style function declarations in kern_malloc.c. MFC after: 3 days
2005-04-12 23:54:34 +00:00
malloc_uninit(void *data)
Have MALLOC_DECLARE() initialize malloc types explicitly, and have them removed at module unload (if in a module of course). However; this introduces a new dependency on <sys/kernel.h> for things that use MALLOC_DECLARE(). Bruce told me it is better to add sys/kernel.h to the handful of files that need it rather than add an extra include to sys/malloc.h for kernel compiles. Updates to follow in subsequent commits.
1998-11-10 08:46:24 +00:00
{
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
struct malloc_type_internal *mtip;
Detect memory leaks when memory type is being destroyed. This is very helpful for detecting kernel modules memory leaks on unload. Discussed and reviewed by: rwatson
2005-11-03 13:48:59 +00:00
struct malloc_type_stats *mtsp;
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
struct malloc_type *mtp, *temp;
Fix bug in malloc_uninit(): Releasing items from the mt_zone can not be done by a simple uma_zfree() call since mt_zone is allocated with the UMA_ZONE_MALLOC flag. Use uma_zfree_arg instead and supply the slab. This bug caused panics in low memory situations on unloading kernel modules containing MALLOC_DEFINE(..) statements. Submitted by: ups
2006-03-03 22:36:52 +00:00
uma_slab_t slab;
Detect memory leaks when memory type is being destroyed. This is very helpful for detecting kernel modules memory leaks on unload. Discussed and reviewed by: rwatson
2005-11-03 13:48:59 +00:00
long temp_allocs, temp_bytes;
int i;
Have MALLOC_DECLARE() initialize malloc types explicitly, and have them removed at module unload (if in a module of course). However; this introduces a new dependency on <sys/kernel.h> for things that use MALLOC_DECLARE(). Bruce told me it is better to add sys/kernel.h to the handful of files that need it rather than add an extra include to sys/malloc.h for kernel compiles. Updates to follow in subsequent commits.
1998-11-10 08:46:24 +00:00
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
mtp = data;
struct malloc_type has had a 'magic' field statically initialized to M_MAGIC by MALLOC_DEFINE() for a long time; add assertions that malloc_type's passed to malloc(), free(), etc have that magic set. MFC after: 2 weeks
2009-04-19 12:41:37 +00:00
KASSERT(mtp->ks_magic == M_MAGIC,
("malloc_uninit: bad malloc type magic"));
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
KASSERT(mtp->ks_handle != NULL, ("malloc_deregister: cookie NULL"));
struct malloc_type has had a 'magic' field statically initialized to M_MAGIC by MALLOC_DEFINE() for a long time; add assertions that malloc_type's passed to malloc(), free(), etc have that magic set. MFC after: 2 weeks
2009-04-19 12:41:37 +00:00
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
mtx_lock(&malloc_mtx);
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
mtip = mtp->ks_handle;
mtp->ks_handle = NULL;
if (mtp != kmemstatistics) {
for (temp = kmemstatistics; temp != NULL;
temp = temp->ks_next) {
If we're passed garbage in malloc_init(), panic() rather than expecting a KASSERT to handle it. People are likely to turn off INVARIANTS RSN and loading an old module can cause garbage-in here. I saw the issue with an older nvidia driver (x11/nvidia-driver) loading into a new kernel - a crash wasn't seen 'till sysctl_kern_malloc_stats(). I was lucky that mtp->ks_shortdesc was NULL and not something horrible. While I'm here, KASSERT that malloc_uninit() isn't passed something that's not in kmemstatistics. MFC after: 3 weeks
2009-06-05 09:16:52 +00:00
if (temp->ks_next == mtp) {
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
temp->ks_next = mtp->ks_next;
If we're passed garbage in malloc_init(), panic() rather than expecting a KASSERT to handle it. People are likely to turn off INVARIANTS RSN and loading an old module can cause garbage-in here. I saw the issue with an older nvidia driver (x11/nvidia-driver) loading into a new kernel - a crash wasn't seen 'till sysctl_kern_malloc_stats(). I was lucky that mtp->ks_shortdesc was NULL and not something horrible. While I'm here, KASSERT that malloc_uninit() isn't passed something that's not in kmemstatistics. MFC after: 3 weeks
2009-06-05 09:16:52 +00:00
break;
}
Have MALLOC_DECLARE() initialize malloc types explicitly, and have them removed at module unload (if in a module of course). However; this introduces a new dependency on <sys/kernel.h> for things that use MALLOC_DECLARE(). Bruce told me it is better to add sys/kernel.h to the handful of files that need it rather than add an extra include to sys/malloc.h for kernel compiles. Updates to follow in subsequent commits.
1998-11-10 08:46:24 +00:00
}
If we're passed garbage in malloc_init(), panic() rather than expecting a KASSERT to handle it. People are likely to turn off INVARIANTS RSN and loading an old module can cause garbage-in here. I saw the issue with an older nvidia driver (x11/nvidia-driver) loading into a new kernel - a crash wasn't seen 'till sysctl_kern_malloc_stats(). I was lucky that mtp->ks_shortdesc was NULL and not something horrible. While I'm here, KASSERT that malloc_uninit() isn't passed something that's not in kmemstatistics. MFC after: 3 weeks
2009-06-05 09:16:52 +00:00
KASSERT(temp,
("malloc_uninit: type '%s' not found", mtp->ks_shortdesc));
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
} else
kmemstatistics = mtp->ks_next;
Introduce a new sysctl, kern.malloc_stats, which exports kernel malloc statistics via a binary structure stream: - Add structure 'malloc_type_stream_header', which defines a stream version, definition of MAXCPUS used in the stream, and a number of malloc_type records in the stream. - Add structure 'malloc_type_header', which defines the name of the malloc type being reported on. - When the sysctl is queried, return a stream header, followed by a series of type descriptions, each consisting of a type header followed by a series of MAXCPUS malloc_type_stats structures holding per-CPU allocation information. Typical values of MAXCPUS will be 1 (UP compiled kernel) and 16 (SMP compiled kernel). This query mechanism allows user space monitoring tools to extract memory allocation statistics in a machine-readable form, and to do so at a per-CPU granularity, allowing monitoring of allocation patterns across CPUs in order to better understand the distribution of work and memory flow over multiple CPUs. While here: - Bump statistics width to uint64_t, and hard code using fixed-width type in order to be more sure about structure layout in the stream. We allocate and free a lot of memory. - Add kmemcount, a counter of the number of registered malloc types, in order to avoid excessive manual counting of types. Export via a new sysctl to allow user-space code to better size buffers. - De-XXX comment on no longer maintaining the high watermark in old sysctl monitoring code. A follow-up commit of libmemstat(3), a library to monitor kernel memory allocation, will occur in the next few days. Likewise, similar changes to UMA.
2005-07-14 11:52:06 +00:00
kmemcount--;
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
mtx_unlock(&malloc_mtx);
Detect memory leaks when memory type is being destroyed. This is very helpful for detecting kernel modules memory leaks on unload. Discussed and reviewed by: rwatson
2005-11-03 13:48:59 +00:00
/*
* Look for memory leaks.
*/
temp_allocs = temp_bytes = 0;
for (i = 0; i < MAXCPU; i++) {
mtsp = &mtip->mti_stats[i];
temp_allocs += mtsp->mts_numallocs;
temp_allocs -= mtsp->mts_numfrees;
temp_bytes += mtsp->mts_memalloced;
temp_bytes -= mtsp->mts_memfreed;
}
if (temp_allocs > 0 || temp_bytes > 0) {
printf("Warning: memory type %s leaked memory on destroy "
"(%ld allocations, %ld bytes leaked).\n", mtp->ks_shortdesc,
temp_allocs, temp_bytes);
}
Fix bug in malloc_uninit(): Releasing items from the mt_zone can not be done by a simple uma_zfree() call since mt_zone is allocated with the UMA_ZONE_MALLOC flag. Use uma_zfree_arg instead and supply the slab. This bug caused panics in low memory situations on unloading kernel modules containing MALLOC_DEFINE(..) statements. Submitted by: ups
2006-03-03 22:36:52 +00:00
slab = vtoslab((vm_offset_t) mtip & (~UMA_SLAB_MASK));
uma_zfree_arg(mt_zone, mtip, slab);
Have MALLOC_DECLARE() initialize malloc types explicitly, and have them removed at module unload (if in a module of course). However; this introduces a new dependency on <sys/kernel.h> for things that use MALLOC_DECLARE(). Bruce told me it is better to add sys/kernel.h to the handful of files that need it rather than add an extra include to sys/malloc.h for kernel compiles. Updates to follow in subsequent commits.
1998-11-10 08:46:24 +00:00
}
Remove malloc_type's ks_limit. Updated the kmemzones logic such that the ks_size bitmap can be used as an index into it to report the size of the zone used. Create the kern.malloc sysctl which replaces the kvm mechanism to report similar data. This will provide an easy place for statistics aggregation if malloc_type statistics become per cpu data. Add some code ifdef'd under MALLOC_PROFILING to facilitate a tool for sizing the malloc buckets.
2002-04-15 04:05:53 +00:00
Improve memguard a bit: - Provide tunable vm.memguard.desc, so one can specify memory type without changing the code and recompiling the kernel. - Allow to use memguard for kernel modules by providing sysctl vm.memguard.desc, which can be changed to short description of memory type before module is loaded. - Move as much memguard code as possible to memguard.c. - Add sysctl node vm.memguard. and move memguard-specific sysctl there. - Add malloc_desc2type() function for finding memory type based on its short description (ks_shortdesc field). - Memory type can be changed (via vm.memguard.desc sysctl) only if it doesn't exist (will be loaded later) or when no memory is allocated yet. If there is allocated memory for the given memory type, return EBUSY. - Implement two ways of memory types comparsion and make safer/slower the default.
2005-12-30 11:45:07 +00:00
struct malloc_type *
malloc_desc2type(const char *desc)
{
struct malloc_type *mtp;
mtx_assert(&malloc_mtx, MA_OWNED);
for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
if (strcmp(mtp->ks_shortdesc, desc) == 0)
return (mtp);
}
return (NULL);
}
Introduce a new sysctl, kern.malloc_stats, which exports kernel malloc statistics via a binary structure stream: - Add structure 'malloc_type_stream_header', which defines a stream version, definition of MAXCPUS used in the stream, and a number of malloc_type records in the stream. - Add structure 'malloc_type_header', which defines the name of the malloc type being reported on. - When the sysctl is queried, return a stream header, followed by a series of type descriptions, each consisting of a type header followed by a series of MAXCPUS malloc_type_stats structures holding per-CPU allocation information. Typical values of MAXCPUS will be 1 (UP compiled kernel) and 16 (SMP compiled kernel). This query mechanism allows user space monitoring tools to extract memory allocation statistics in a machine-readable form, and to do so at a per-CPU granularity, allowing monitoring of allocation patterns across CPUs in order to better understand the distribution of work and memory flow over multiple CPUs. While here: - Bump statistics width to uint64_t, and hard code using fixed-width type in order to be more sure about structure layout in the stream. We allocate and free a lot of memory. - Add kmemcount, a counter of the number of registered malloc types, in order to avoid excessive manual counting of types. Export via a new sysctl to allow user-space code to better size buffers. - De-XXX comment on no longer maintaining the high watermark in old sysctl monitoring code. A follow-up commit of libmemstat(3), a library to monitor kernel memory allocation, will occur in the next few days. Likewise, similar changes to UMA.
2005-07-14 11:52:06 +00:00
static int
sysctl_kern_malloc_stats(SYSCTL_HANDLER_ARGS)
{
struct malloc_type_stream_header mtsh;
struct malloc_type_internal *mtip;
struct malloc_type_header mth;
struct malloc_type *mtp;
Re-add r212370 now that the LOR in powerpc64 has been resolved: Add a drain function for struct sysctl_req, and use it for a variety of handlers, some of which had to do awkward things to get a large enough SBUF_FIXEDLEN buffer. Note that some sysctl handlers were explicitly outputting a trailing NUL byte. This behaviour was preserved, though it should not be necessary. Reviewed by: phk (original patch)
2010-09-16 16:13:12 +00:00
int error, i;
Introduce a new sysctl, kern.malloc_stats, which exports kernel malloc statistics via a binary structure stream: - Add structure 'malloc_type_stream_header', which defines a stream version, definition of MAXCPUS used in the stream, and a number of malloc_type records in the stream. - Add structure 'malloc_type_header', which defines the name of the malloc type being reported on. - When the sysctl is queried, return a stream header, followed by a series of type descriptions, each consisting of a type header followed by a series of MAXCPUS malloc_type_stats structures holding per-CPU allocation information. Typical values of MAXCPUS will be 1 (UP compiled kernel) and 16 (SMP compiled kernel). This query mechanism allows user space monitoring tools to extract memory allocation statistics in a machine-readable form, and to do so at a per-CPU granularity, allowing monitoring of allocation patterns across CPUs in order to better understand the distribution of work and memory flow over multiple CPUs. While here: - Bump statistics width to uint64_t, and hard code using fixed-width type in order to be more sure about structure layout in the stream. We allocate and free a lot of memory. - Add kmemcount, a counter of the number of registered malloc types, in order to avoid excessive manual counting of types. Export via a new sysctl to allow user-space code to better size buffers. - De-XXX comment on no longer maintaining the high watermark in old sysctl monitoring code. A follow-up commit of libmemstat(3), a library to monitor kernel memory allocation, will occur in the next few days. Likewise, similar changes to UMA.
2005-07-14 11:52:06 +00:00
struct sbuf sbuf;
Explicitly wire the user buffer rather than doing it implicitly in sbuf_new_for_sysctl(9). This allows using an sbuf with a SYSCTL_OUT drain for extremely large amounts of data where the caller knows that appropriate references are held, and sleeping is not an issue. Inspired by: rwatson
2011-01-27 00:34:12 +00:00
error = sysctl_wire_old_buffer(req, 0);
if (error != 0)
return (error);
Re-add r212370 now that the LOR in powerpc64 has been resolved: Add a drain function for struct sysctl_req, and use it for a variety of handlers, some of which had to do awkward things to get a large enough SBUF_FIXEDLEN buffer. Note that some sysctl handlers were explicitly outputting a trailing NUL byte. This behaviour was preserved, though it should not be necessary. Reviewed by: phk (original patch)
2010-09-16 16:13:12 +00:00
sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
Set the SBUF_INCLUDENUL flag in sbuf_new_for_sysctl() so that sysctl strings returned to userland include the nulterm byte. Some uses of sbuf_new_for_sysctl() write binary data rather than strings; clear the SBUF_INCLUDENUL flag after calling sbuf_new_for_sysctl() in those cases. (Note that the sbuf code still automatically adds a nulterm byte in sbuf_finish(), but since it's not included in the length it won't get copied to userland along with the binary data.) Remove explicit adding of a nulterm byte in a couple places now that it gets done automatically by the sbuf drain code. PR: 195668
2015-03-14 17:08:28 +00:00
sbuf_clear_flags(&sbuf, SBUF_INCLUDENUL);
Introduce a new sysctl, kern.malloc_stats, which exports kernel malloc statistics via a binary structure stream: - Add structure 'malloc_type_stream_header', which defines a stream version, definition of MAXCPUS used in the stream, and a number of malloc_type records in the stream. - Add structure 'malloc_type_header', which defines the name of the malloc type being reported on. - When the sysctl is queried, return a stream header, followed by a series of type descriptions, each consisting of a type header followed by a series of MAXCPUS malloc_type_stats structures holding per-CPU allocation information. Typical values of MAXCPUS will be 1 (UP compiled kernel) and 16 (SMP compiled kernel). This query mechanism allows user space monitoring tools to extract memory allocation statistics in a machine-readable form, and to do so at a per-CPU granularity, allowing monitoring of allocation patterns across CPUs in order to better understand the distribution of work and memory flow over multiple CPUs. While here: - Bump statistics width to uint64_t, and hard code using fixed-width type in order to be more sure about structure layout in the stream. We allocate and free a lot of memory. - Add kmemcount, a counter of the number of registered malloc types, in order to avoid excessive manual counting of types. Export via a new sysctl to allow user-space code to better size buffers. - De-XXX comment on no longer maintaining the high watermark in old sysctl monitoring code. A follow-up commit of libmemstat(3), a library to monitor kernel memory allocation, will occur in the next few days. Likewise, similar changes to UMA.
2005-07-14 11:52:06 +00:00
mtx_lock(&malloc_mtx);
/*
* Insert stream header.
*/
bzero(&mtsh, sizeof(mtsh));
mtsh.mtsh_version = MALLOC_TYPE_STREAM_VERSION;
mtsh.mtsh_maxcpus = MAXCPU;
mtsh.mtsh_count = kmemcount;
Re-add r212370 now that the LOR in powerpc64 has been resolved: Add a drain function for struct sysctl_req, and use it for a variety of handlers, some of which had to do awkward things to get a large enough SBUF_FIXEDLEN buffer. Note that some sysctl handlers were explicitly outputting a trailing NUL byte. This behaviour was preserved, though it should not be necessary. Reviewed by: phk (original patch)
2010-09-16 16:13:12 +00:00
(void)sbuf_bcat(&sbuf, &mtsh, sizeof(mtsh));
Introduce a new sysctl, kern.malloc_stats, which exports kernel malloc statistics via a binary structure stream: - Add structure 'malloc_type_stream_header', which defines a stream version, definition of MAXCPUS used in the stream, and a number of malloc_type records in the stream. - Add structure 'malloc_type_header', which defines the name of the malloc type being reported on. - When the sysctl is queried, return a stream header, followed by a series of type descriptions, each consisting of a type header followed by a series of MAXCPUS malloc_type_stats structures holding per-CPU allocation information. Typical values of MAXCPUS will be 1 (UP compiled kernel) and 16 (SMP compiled kernel). This query mechanism allows user space monitoring tools to extract memory allocation statistics in a machine-readable form, and to do so at a per-CPU granularity, allowing monitoring of allocation patterns across CPUs in order to better understand the distribution of work and memory flow over multiple CPUs. While here: - Bump statistics width to uint64_t, and hard code using fixed-width type in order to be more sure about structure layout in the stream. We allocate and free a lot of memory. - Add kmemcount, a counter of the number of registered malloc types, in order to avoid excessive manual counting of types. Export via a new sysctl to allow user-space code to better size buffers. - De-XXX comment on no longer maintaining the high watermark in old sysctl monitoring code. A follow-up commit of libmemstat(3), a library to monitor kernel memory allocation, will occur in the next few days. Likewise, similar changes to UMA.
2005-07-14 11:52:06 +00:00
/*
* Insert alternating sequence of type headers and type statistics.
*/
for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
mtip = (struct malloc_type_internal *)mtp->ks_handle;
/*
* Insert type header.
*/
bzero(&mth, sizeof(mth));
strlcpy(mth.mth_name, mtp->ks_shortdesc, MALLOC_MAX_NAME);
Re-add r212370 now that the LOR in powerpc64 has been resolved: Add a drain function for struct sysctl_req, and use it for a variety of handlers, some of which had to do awkward things to get a large enough SBUF_FIXEDLEN buffer. Note that some sysctl handlers were explicitly outputting a trailing NUL byte. This behaviour was preserved, though it should not be necessary. Reviewed by: phk (original patch)
2010-09-16 16:13:12 +00:00
(void)sbuf_bcat(&sbuf, &mth, sizeof(mth));
Introduce a new sysctl, kern.malloc_stats, which exports kernel malloc statistics via a binary structure stream: - Add structure 'malloc_type_stream_header', which defines a stream version, definition of MAXCPUS used in the stream, and a number of malloc_type records in the stream. - Add structure 'malloc_type_header', which defines the name of the malloc type being reported on. - When the sysctl is queried, return a stream header, followed by a series of type descriptions, each consisting of a type header followed by a series of MAXCPUS malloc_type_stats structures holding per-CPU allocation information. Typical values of MAXCPUS will be 1 (UP compiled kernel) and 16 (SMP compiled kernel). This query mechanism allows user space monitoring tools to extract memory allocation statistics in a machine-readable form, and to do so at a per-CPU granularity, allowing monitoring of allocation patterns across CPUs in order to better understand the distribution of work and memory flow over multiple CPUs. While here: - Bump statistics width to uint64_t, and hard code using fixed-width type in order to be more sure about structure layout in the stream. We allocate and free a lot of memory. - Add kmemcount, a counter of the number of registered malloc types, in order to avoid excessive manual counting of types. Export via a new sysctl to allow user-space code to better size buffers. - De-XXX comment on no longer maintaining the high watermark in old sysctl monitoring code. A follow-up commit of libmemstat(3), a library to monitor kernel memory allocation, will occur in the next few days. Likewise, similar changes to UMA.
2005-07-14 11:52:06 +00:00
/*
* Insert type statistics for each CPU.
*/
for (i = 0; i < MAXCPU; i++) {
Re-add r212370 now that the LOR in powerpc64 has been resolved: Add a drain function for struct sysctl_req, and use it for a variety of handlers, some of which had to do awkward things to get a large enough SBUF_FIXEDLEN buffer. Note that some sysctl handlers were explicitly outputting a trailing NUL byte. This behaviour was preserved, though it should not be necessary. Reviewed by: phk (original patch)
2010-09-16 16:13:12 +00:00
(void)sbuf_bcat(&sbuf, &mtip->mti_stats[i],
sizeof(mtip->mti_stats[i]));
Introduce a new sysctl, kern.malloc_stats, which exports kernel malloc statistics via a binary structure stream: - Add structure 'malloc_type_stream_header', which defines a stream version, definition of MAXCPUS used in the stream, and a number of malloc_type records in the stream. - Add structure 'malloc_type_header', which defines the name of the malloc type being reported on. - When the sysctl is queried, return a stream header, followed by a series of type descriptions, each consisting of a type header followed by a series of MAXCPUS malloc_type_stats structures holding per-CPU allocation information. Typical values of MAXCPUS will be 1 (UP compiled kernel) and 16 (SMP compiled kernel). This query mechanism allows user space monitoring tools to extract memory allocation statistics in a machine-readable form, and to do so at a per-CPU granularity, allowing monitoring of allocation patterns across CPUs in order to better understand the distribution of work and memory flow over multiple CPUs. While here: - Bump statistics width to uint64_t, and hard code using fixed-width type in order to be more sure about structure layout in the stream. We allocate and free a lot of memory. - Add kmemcount, a counter of the number of registered malloc types, in order to avoid excessive manual counting of types. Export via a new sysctl to allow user-space code to better size buffers. - De-XXX comment on no longer maintaining the high watermark in old sysctl monitoring code. A follow-up commit of libmemstat(3), a library to monitor kernel memory allocation, will occur in the next few days. Likewise, similar changes to UMA.
2005-07-14 11:52:06 +00:00
}
}
mtx_unlock(&malloc_mtx);
Re-add r212370 now that the LOR in powerpc64 has been resolved: Add a drain function for struct sysctl_req, and use it for a variety of handlers, some of which had to do awkward things to get a large enough SBUF_FIXEDLEN buffer. Note that some sysctl handlers were explicitly outputting a trailing NUL byte. This behaviour was preserved, though it should not be necessary. Reviewed by: phk (original patch)
2010-09-16 16:13:12 +00:00
error = sbuf_finish(&sbuf);
Introduce a new sysctl, kern.malloc_stats, which exports kernel malloc statistics via a binary structure stream: - Add structure 'malloc_type_stream_header', which defines a stream version, definition of MAXCPUS used in the stream, and a number of malloc_type records in the stream. - Add structure 'malloc_type_header', which defines the name of the malloc type being reported on. - When the sysctl is queried, return a stream header, followed by a series of type descriptions, each consisting of a type header followed by a series of MAXCPUS malloc_type_stats structures holding per-CPU allocation information. Typical values of MAXCPUS will be 1 (UP compiled kernel) and 16 (SMP compiled kernel). This query mechanism allows user space monitoring tools to extract memory allocation statistics in a machine-readable form, and to do so at a per-CPU granularity, allowing monitoring of allocation patterns across CPUs in order to better understand the distribution of work and memory flow over multiple CPUs. While here: - Bump statistics width to uint64_t, and hard code using fixed-width type in order to be more sure about structure layout in the stream. We allocate and free a lot of memory. - Add kmemcount, a counter of the number of registered malloc types, in order to avoid excessive manual counting of types. Export via a new sysctl to allow user-space code to better size buffers. - De-XXX comment on no longer maintaining the high watermark in old sysctl monitoring code. A follow-up commit of libmemstat(3), a library to monitor kernel memory allocation, will occur in the next few days. Likewise, similar changes to UMA.
2005-07-14 11:52:06 +00:00
sbuf_delete(&sbuf);
return (error);
}
SYSCTL_PROC(_kern, OID_AUTO, malloc_stats, CTLFLAG_RD|CTLTYPE_STRUCT,
0, 0, sysctl_kern_malloc_stats, "s,malloc_type_ustats",
"Return malloc types");
SYSCTL_INT(_kern, OID_AUTO, malloc_count, CTLFLAG_RD, &kmemcount, 0,
"Count of kernel malloc types");
Add support for the DTrace malloc provider which can enable probes on a per-malloc type basis.
2008-05-23 00:43:36 +00:00
void
malloc_type_list(malloc_type_list_func_t *func, void *arg)
{
struct malloc_type *mtp, **bufmtp;
int count, i;
size_t buflen;
mtx_lock(&malloc_mtx);
restart:
mtx_assert(&malloc_mtx, MA_OWNED);
count = kmemcount;
mtx_unlock(&malloc_mtx);
buflen = sizeof(struct malloc_type *) * count;
bufmtp = malloc(buflen, M_TEMP, M_WAITOK);
mtx_lock(&malloc_mtx);
if (count < kmemcount) {
free(bufmtp, M_TEMP);
goto restart;
}
for (mtp = kmemstatistics, i = 0; mtp != NULL; mtp = mtp->ks_next, i++)
bufmtp[i] = mtp;
mtx_unlock(&malloc_mtx);
for (i = 0; i < count; i++)
(func)(bufmtp[i], arg);
free(bufmtp, M_TEMP);
}
Add a "show malloc" command to DDB, which prints out the current stats for available kernel malloc types. Quite useful for post-mortem debugging of memory leaks without a dump device configured on a panicked box. MFC after: 2 weeks
2005-10-20 17:41:47 +00:00
#ifdef DDB
DB_SHOW_COMMAND(malloc, db_show_malloc)
{
struct malloc_type_internal *mtip;
struct malloc_type *mtp;
Use ISO C99 integer types in sys/kern where possible. There are only about 100 occurences of the BSD-specific u_int*_t datatypes in sys/kern. The ISO C99 integer types are used here more often.
2010-06-21 09:55:56 +00:00
uint64_t allocs, frees;
uint64_t alloced, freed;
Add a "show malloc" command to DDB, which prints out the current stats for available kernel malloc types. Quite useful for post-mortem debugging of memory leaks without a dump device configured on a panicked box. MFC after: 2 weeks
2005-10-20 17:41:47 +00:00
int i;
Increase usefulness of "show malloc" by moving from displaying the basic counters of allocs/frees/use for each malloc type to calculating InUse, MemUse, and Requests as displayed by the userspace vmstat -m. This is more useful when debugging malloc(9)-related memory leaks, where the count of allocs/frees may not usefully reflect that current memory allocation (i.e., when highly variable size allocations occur with the same malloc type, such as with contigmalloc). MFC after: 3 days Limitations observed by: scottl
2006-10-26 10:17:13 +00:00
db_printf("%18s %12s %12s %12s\n", "Type", "InUse", "MemUse",
"Requests");
Add a "show malloc" command to DDB, which prints out the current stats for available kernel malloc types. Quite useful for post-mortem debugging of memory leaks without a dump device configured on a panicked box. MFC after: 2 weeks
2005-10-20 17:41:47 +00:00
for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
mtip = (struct malloc_type_internal *)mtp->ks_handle;
allocs = 0;
frees = 0;
Increase usefulness of "show malloc" by moving from displaying the basic counters of allocs/frees/use for each malloc type to calculating InUse, MemUse, and Requests as displayed by the userspace vmstat -m. This is more useful when debugging malloc(9)-related memory leaks, where the count of allocs/frees may not usefully reflect that current memory allocation (i.e., when highly variable size allocations occur with the same malloc type, such as with contigmalloc). MFC after: 3 days Limitations observed by: scottl
2006-10-26 10:17:13 +00:00
alloced = 0;
freed = 0;
Add a "show malloc" command to DDB, which prints out the current stats for available kernel malloc types. Quite useful for post-mortem debugging of memory leaks without a dump device configured on a panicked box. MFC after: 2 weeks
2005-10-20 17:41:47 +00:00
for (i = 0; i < MAXCPU; i++) {
allocs += mtip->mti_stats[i].mts_numallocs;
frees += mtip->mti_stats[i].mts_numfrees;
Increase usefulness of "show malloc" by moving from displaying the basic counters of allocs/frees/use for each malloc type to calculating InUse, MemUse, and Requests as displayed by the userspace vmstat -m. This is more useful when debugging malloc(9)-related memory leaks, where the count of allocs/frees may not usefully reflect that current memory allocation (i.e., when highly variable size allocations occur with the same malloc type, such as with contigmalloc). MFC after: 3 days Limitations observed by: scottl
2006-10-26 10:17:13 +00:00
alloced += mtip->mti_stats[i].mts_memalloced;
freed += mtip->mti_stats[i].mts_memfreed;
Add a "show malloc" command to DDB, which prints out the current stats for available kernel malloc types. Quite useful for post-mortem debugging of memory leaks without a dump device configured on a panicked box. MFC after: 2 weeks
2005-10-20 17:41:47 +00:00
}
Increase usefulness of "show malloc" by moving from displaying the basic counters of allocs/frees/use for each malloc type to calculating InUse, MemUse, and Requests as displayed by the userspace vmstat -m. This is more useful when debugging malloc(9)-related memory leaks, where the count of allocs/frees may not usefully reflect that current memory allocation (i.e., when highly variable size allocations occur with the same malloc type, such as with contigmalloc). MFC after: 3 days Limitations observed by: scottl
2006-10-26 10:17:13 +00:00
db_printf("%18s %12ju %12juK %12ju\n",
mtp->ks_shortdesc, allocs - frees,
(alloced - freed + 1023) / 1024, allocs);
Honor db_pager_quit in 'show uma' and 'show malloc'. MFC after: 1 month
2012-07-02 16:14:52 +00:00
if (db_pager_quit)
break;
Add a "show malloc" command to DDB, which prints out the current stats for available kernel malloc types. Quite useful for post-mortem debugging of memory leaks without a dump device configured on a panicked box. MFC after: 2 weeks
2005-10-20 17:41:47 +00:00
}
}
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
#if MALLOC_DEBUG_MAXZONES > 1
DB_SHOW_COMMAND(multizone_matches, db_show_multizone_matches)
{
struct malloc_type_internal *mtip;
struct malloc_type *mtp;
u_int subzone;
if (!have_addr) {
db_printf("Usage: show multizone_matches <malloc type/addr>\n");
return;
}
mtp = (void *)addr;
if (mtp->ks_magic != M_MAGIC) {
db_printf("Magic %lx does not match expected %x\n",
mtp->ks_magic, M_MAGIC);
return;
}
mtip = mtp->ks_handle;
subzone = mtip->mti_zone;
for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
mtip = mtp->ks_handle;
if (mtip->mti_zone != subzone)
continue;
db_printf("%s\n", mtp->ks_shortdesc);
Honor db_pager_quit in 'show uma' and 'show malloc'. MFC after: 1 month
2012-07-02 16:14:52 +00:00
if (db_pager_quit)
break;
Add MALLOC_DEBUG_MAXZONES debug malloc(9) option to use multiple uma zones for each malloc bucket size. The purpose is to isolate different malloc types into hash classes, so that any buffer overruns or use-after-free will usually only affect memory from malloc types in that hash class. This is purely a debugging tool; by varying the hash function and tracking which hash class was corrupted, the intersection of the hash classes from each instance will point to a single malloc type that is being misused. At this point inspection or memguard(9) can be used to catch the offending code. Add MALLOC_DEBUG_MAXZONES=8 to -current GENERIC configuration files. The suggestion to have this on by default came from Kostik Belousov on -arch. This code is based on work by Ron Steinke at Isilon Systems. Reviewed by: -arch (mostly silence) Reviewed by: zml Approved by: zml (mentor)
2010-07-28 15:36:12 +00:00
}
}
#endif /* MALLOC_DEBUG_MAXZONES > 1 */
#endif /* DDB */
Add a "show malloc" command to DDB, which prints out the current stats for available kernel malloc types. Quite useful for post-mortem debugging of memory leaks without a dump device configured on a panicked box. MFC after: 2 weeks
2005-10-20 17:41:47 +00:00
Finish adding support code for sysctl kern.mprof. This dumps some malloc information related to bucket size effeciency. Three things are printed on each row: Size is the size the user actually asked for rounded to 16 bytes. Requests is the number of times this size was asked for. Real Size is the size we actually handed out. At the end the total memory used and total waste is displayed. Currently my system displays about 33% wasted memory. The intent of this code is to gather statistics for tuning the malloc bucket sizes. It is not intended to be run with INVARIANTS and it is not entirely mp safe. It can be enabled via 'options MALLOC_PROFILE' which was commited earlier.
2002-04-15 05:24:01 +00:00
#ifdef MALLOC_PROFILE
static int
sysctl_kern_mprof(SYSCTL_HANDLER_ARGS)
{
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
struct sbuf sbuf;
Finish adding support code for sysctl kern.mprof. This dumps some malloc information related to bucket size effeciency. Three things are printed on each row: Size is the size the user actually asked for rounded to 16 bytes. Requests is the number of times this size was asked for. Real Size is the size we actually handed out. At the end the total memory used and total waste is displayed. Currently my system displays about 33% wasted memory. The intent of this code is to gather statistics for tuning the malloc bucket sizes. It is not intended to be run with INVARIANTS and it is not entirely mp safe. It can be enabled via 'options MALLOC_PROFILE' which was commited earlier.
2002-04-15 05:24:01 +00:00
uint64_t count;
uint64_t waste;
uint64_t mem;
int error;
int rsize;
int size;
int i;
waste = 0;
mem = 0;
Explicitly wire the user buffer rather than doing it implicitly in sbuf_new_for_sysctl(9). This allows using an sbuf with a SYSCTL_OUT drain for extremely large amounts of data where the caller knows that appropriate references are held, and sleeping is not an issue. Inspired by: rwatson
2011-01-27 00:34:12 +00:00
error = sysctl_wire_old_buffer(req, 0);
if (error != 0)
return (error);
Re-add r212370 now that the LOR in powerpc64 has been resolved: Add a drain function for struct sysctl_req, and use it for a variety of handlers, some of which had to do awkward things to get a large enough SBUF_FIXEDLEN buffer. Note that some sysctl handlers were explicitly outputting a trailing NUL byte. This behaviour was preserved, though it should not be necessary. Reviewed by: phk (original patch)
2010-09-16 16:13:12 +00:00
sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
sbuf_printf(&sbuf,
Finish adding support code for sysctl kern.mprof. This dumps some malloc information related to bucket size effeciency. Three things are printed on each row: Size is the size the user actually asked for rounded to 16 bytes. Requests is the number of times this size was asked for. Real Size is the size we actually handed out. At the end the total memory used and total waste is displayed. Currently my system displays about 33% wasted memory. The intent of this code is to gather statistics for tuning the malloc bucket sizes. It is not intended to be run with INVARIANTS and it is not entirely mp safe. It can be enabled via 'options MALLOC_PROFILE' which was commited earlier.
2002-04-15 05:24:01 +00:00
"\n Size Requests Real Size\n");
for (i = 0; i < KMEM_ZSIZE; i++) {
size = i << KMEM_ZSHIFT;
rsize = kmemzones[kmemsize[i]].kz_size;
count = (long long unsigned)krequests[i];
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
sbuf_printf(&sbuf, "%6d%28llu%11d\n", size,
(unsigned long long)count, rsize);
Finish adding support code for sysctl kern.mprof. This dumps some malloc information related to bucket size effeciency. Three things are printed on each row: Size is the size the user actually asked for rounded to 16 bytes. Requests is the number of times this size was asked for. Real Size is the size we actually handed out. At the end the total memory used and total waste is displayed. Currently my system displays about 33% wasted memory. The intent of this code is to gather statistics for tuning the malloc bucket sizes. It is not intended to be run with INVARIANTS and it is not entirely mp safe. It can be enabled via 'options MALLOC_PROFILE' which was commited earlier.
2002-04-15 05:24:01 +00:00
if ((rsize * count) > (size * count))
waste += (rsize * count) - (size * count);
mem += (rsize * count);
}
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
sbuf_printf(&sbuf,
Finish adding support code for sysctl kern.mprof. This dumps some malloc information related to bucket size effeciency. Three things are printed on each row: Size is the size the user actually asked for rounded to 16 bytes. Requests is the number of times this size was asked for. Real Size is the size we actually handed out. At the end the total memory used and total waste is displayed. Currently my system displays about 33% wasted memory. The intent of this code is to gather statistics for tuning the malloc bucket sizes. It is not intended to be run with INVARIANTS and it is not entirely mp safe. It can be enabled via 'options MALLOC_PROFILE' which was commited earlier.
2002-04-15 05:24:01 +00:00
"\nTotal memory used:\t%30llu\nTotal Memory wasted:\t%30llu\n",
(unsigned long long)mem, (unsigned long long)waste);
Re-add r212370 now that the LOR in powerpc64 has been resolved: Add a drain function for struct sysctl_req, and use it for a variety of handlers, some of which had to do awkward things to get a large enough SBUF_FIXEDLEN buffer. Note that some sysctl handlers were explicitly outputting a trailing NUL byte. This behaviour was preserved, though it should not be necessary. Reviewed by: phk (original patch)
2010-09-16 16:13:12 +00:00
error = sbuf_finish(&sbuf);
Kernel malloc layers malloc_type allocation over one of two underlying allocators: a set of power-of-two UMA zones for small allocations, and the VM page allocator for large allocations. In order to maintain unified statistics for specific malloc types, kernel malloc maintains a separate per-type statistics pool, which can be monitored using vmstat -m. Prior to this commit, each pool of per-type statistics was protected using a per-type mutex associated with the malloc type. This change modifies kernel malloc to maintain per-CPU statistics pools for each malloc type, and protects writing those statistics using critical sections. It also moves to unsynchronized reads of per-CPU statistics when generating coalesced statistics. To do this, several changes are implemented: - In the previous world order, the statistics memory was allocated by the owner of the malloc type structure, allocated statically using MALLOC_DEFINE(). This embedded the definition of the malloc_type structure into all kernel modules. Move to a model in which a pointer within struct malloc_type points at a UMA-allocated malloc_type_internal data structure owned and maintained by kern_malloc.c, and not part of the exported ABI/API to the rest of the kernel. For the purposes of easing a possible MFC, re-use an existing pointer in 'struct malloc_type', and maintain the current malloc_type structure size, as well as layout with respect to the fields reused outside of the malloc subsystem (such as ks_shortdesc). There are several unused fields as a result of no longer requiring the mutex in malloc_type. - Struct malloc_type_internal contains an array of malloc_type_stats, of size MAXCPU. The structure defined above avoids hard-coding a kernel compile-time value of MAXCPU into kernel modules that interact with malloc. - When accessing per-cpu statistics for a malloc type, surround read - modify - update requests with critical_enter()/critical_exit() in order to avoid races during write. The per-CPU fields are written only from the CPU that owns them. - Per-CPU stats now maintained "allocated" and "freed" counters for number of allocations/frees and bytes allocated/freed, since there is no longer a coherent global notion of the totals. When coalescing malloc stats, accept a slight race between reading stats across CPUs, and avoid showing the user a negative allocation count for the type in the event of a race. The global high watermark is no longer maintained for a malloc type, as there is no global notion of the number of allocations. - While tearing up the sysctl() path, also switch to using sbufs. The current "export as text" sysctl format is retained with the same syntax. We may want to change this in the future to export more per-CPU information, such as how allocations and frees are balanced across CPUs. This change results in a substantial speedup of kernel malloc and free paths on SMP, as critical sections (where usable) out-perform mutexes due to avoiding atomic/bus-locked operations. There is also a minor improvement on UP due to the slightly lower cost of critical sections there. The cost of the change to this approach is the loss of a continuous notion of total allocations that can be exploited to track per-type high watermarks, as well as increased complexity when monitoring statistics. Due to carefully avoiding changing the ABI, as well as hardening the ABI against future changes, it is not necessary to recompile kernel modules for this change. However, MFC'ing this change to RELENG_5 will require also MFC'ing optimizations for soft critical sections, which may modify exposed kernel ABIs. The internal malloc API is changed, and modifications to vmstat in order to restore "vmstat -m" on core dumps will follow shortly. Several improvements from: bde Statistics approach discussed with: ups Tested by: scottl, others
2005-05-29 13:38:07 +00:00
sbuf_delete(&sbuf);
Finish adding support code for sysctl kern.mprof. This dumps some malloc information related to bucket size effeciency. Three things are printed on each row: Size is the size the user actually asked for rounded to 16 bytes. Requests is the number of times this size was asked for. Real Size is the size we actually handed out. At the end the total memory used and total waste is displayed. Currently my system displays about 33% wasted memory. The intent of this code is to gather statistics for tuning the malloc bucket sizes. It is not intended to be run with INVARIANTS and it is not entirely mp safe. It can be enabled via 'options MALLOC_PROFILE' which was commited earlier.
2002-04-15 05:24:01 +00:00
return (error);
}
SYSCTL_OID(_kern, OID_AUTO, mprof, CTLTYPE_STRING|CTLFLAG_RD,
NULL, 0, sysctl_kern_mprof, "A", "Malloc Profiling");
#endif /* MALLOC_PROFILE */
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