7c26a038f9
do not map the b_pages pages into buffer_map KVA. The use of the unmapped buffers eliminate the need to perform TLB shootdown for mapping on the buffer creation and reuse, greatly reducing the amount of IPIs for shootdown on big-SMP machines and eliminating up to 25-30% of the system time on i/o intensive workloads. The unmapped buffer should be explicitely requested by the GB_UNMAPPED flag by the consumer. For unmapped buffer, no KVA reservation is performed at all. The consumer might request unmapped buffer which does have a KVA reserve, to manually map it without recursing into buffer cache and blocking, with the GB_KVAALLOC flag. When the mapped buffer is requested and unmapped buffer already exists, the cache performs an upgrade, possibly reusing the KVA reservation. Unmapped buffer is translated into unmapped bio in g_vfs_strategy(). Unmapped bio carry a pointer to the vm_page_t array, offset and length instead of the data pointer. The provider which processes the bio should explicitely specify a readiness to accept unmapped bio, otherwise g_down geom thread performs the transient upgrade of the bio request by mapping the pages into the new bio_transient_map KVA submap. The bio_transient_map submap claims up to 10% of the buffer map, and the total buffer_map + bio_transient_map KVA usage stays the same. Still, it could be manually tuned by kern.bio_transient_maxcnt tunable, in the units of the transient mappings. Eventually, the bio_transient_map could be removed after all geom classes and drivers can accept unmapped i/o requests. Unmapped support can be turned off by the vfs.unmapped_buf_allowed tunable, disabling which makes the buffer (or cluster) creation requests to ignore GB_UNMAPPED and GB_KVAALLOC flags. Unmapped buffers are only enabled by default on the architectures where pmap_copy_page() was implemented and tested. In the rework, filesystem metadata is not the subject to maxbufspace limit anymore. Since the metadata buffers are always mapped, the buffers still have to fit into the buffer map, which provides a reasonable (but practically unreachable) upper bound on it. The non-metadata buffer allocations, both mapped and unmapped, is accounted against maxbufspace, as before. Effectively, this means that the maxbufspace is forced on mapped and unmapped buffers separately. The pre-patch bufspace limiting code did not worked, because buffer_map fragmentation does not allow the limit to be reached. By Jeff Roberson request, the getnewbuf() function was split into smaller single-purpose functions. Sponsored by: The FreeBSD Foundation Discussed with: jeff (previous version) Tested by: pho, scottl (previous version), jhb, bf MFC after: 2 weeks
355 lines
11 KiB
C
355 lines
11 KiB
C
/*-
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* Copyright (c) 1980, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)param.c 8.3 (Berkeley) 8/20/94
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_param.h"
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#include "opt_msgbuf.h"
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#include "opt_maxusers.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/limits.h>
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#include <sys/msgbuf.h>
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#include <sys/sysctl.h>
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#include <sys/proc.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/pmap.h>
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/*
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* System parameter formulae.
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*/
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#ifndef HZ
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# if defined(__mips__) || defined(__arm__)
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# define HZ 100
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# else
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# define HZ 1000
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# endif
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# ifndef HZ_VM
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# define HZ_VM 100
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# endif
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#else
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# ifndef HZ_VM
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# define HZ_VM HZ
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# endif
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#endif
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#define NPROC (20 + 16 * maxusers)
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#ifndef NBUF
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#define NBUF 0
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#endif
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#ifndef MAXFILES
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#define MAXFILES (maxproc * 2)
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#endif
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static int sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS);
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int hz; /* system clock's frequency */
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int tick; /* usec per tick (1000000 / hz) */
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struct bintime tick_bt; /* bintime per tick (1s / hz) */
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sbintime_t tick_sbt;
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int maxusers; /* base tunable */
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int maxproc; /* maximum # of processes */
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int maxprocperuid; /* max # of procs per user */
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int maxfiles; /* sys. wide open files limit */
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int maxfilesperproc; /* per-proc open files limit */
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int msgbufsize; /* size of kernel message buffer */
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int nbuf;
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int bio_transient_maxcnt;
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int ngroups_max; /* max # groups per process */
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int nswbuf;
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pid_t pid_max = PID_MAX;
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long maxswzone; /* max swmeta KVA storage */
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long maxbcache; /* max buffer cache KVA storage */
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long maxpipekva; /* Limit on pipe KVA */
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int vm_guest; /* Running as virtual machine guest? */
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u_long maxtsiz; /* max text size */
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u_long dfldsiz; /* initial data size limit */
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u_long maxdsiz; /* max data size */
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u_long dflssiz; /* initial stack size limit */
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u_long maxssiz; /* max stack size */
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u_long sgrowsiz; /* amount to grow stack */
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SYSCTL_INT(_kern, OID_AUTO, hz, CTLFLAG_RDTUN, &hz, 0,
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"Number of clock ticks per second");
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SYSCTL_INT(_kern, OID_AUTO, nbuf, CTLFLAG_RDTUN, &nbuf, 0,
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"Number of buffers in the buffer cache");
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SYSCTL_INT(_kern, OID_AUTO, nswbuf, CTLFLAG_RDTUN, &nswbuf, 0,
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"Number of swap buffers");
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SYSCTL_INT(_kern, OID_AUTO, msgbufsize, CTLFLAG_RDTUN, &msgbufsize, 0,
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"Size of the kernel message buffer");
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SYSCTL_LONG(_kern, OID_AUTO, maxswzone, CTLFLAG_RDTUN, &maxswzone, 0,
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"Maximum memory for swap metadata");
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SYSCTL_LONG(_kern, OID_AUTO, maxbcache, CTLFLAG_RDTUN, &maxbcache, 0,
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"Maximum value of vfs.maxbufspace");
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SYSCTL_INT(_kern, OID_AUTO, bio_transient_maxcnt, CTLFLAG_RDTUN,
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&bio_transient_maxcnt, 0,
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"Maximum number of transient BIOs mappings");
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SYSCTL_ULONG(_kern, OID_AUTO, maxtsiz, CTLFLAG_RW | CTLFLAG_TUN, &maxtsiz, 0,
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"Maximum text size");
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SYSCTL_ULONG(_kern, OID_AUTO, dfldsiz, CTLFLAG_RW | CTLFLAG_TUN, &dfldsiz, 0,
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"Initial data size limit");
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SYSCTL_ULONG(_kern, OID_AUTO, maxdsiz, CTLFLAG_RW | CTLFLAG_TUN, &maxdsiz, 0,
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"Maximum data size");
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SYSCTL_ULONG(_kern, OID_AUTO, dflssiz, CTLFLAG_RW | CTLFLAG_TUN, &dflssiz, 0,
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"Initial stack size limit");
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SYSCTL_ULONG(_kern, OID_AUTO, maxssiz, CTLFLAG_RW | CTLFLAG_TUN, &maxssiz, 0,
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"Maximum stack size");
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SYSCTL_ULONG(_kern, OID_AUTO, sgrowsiz, CTLFLAG_RW | CTLFLAG_TUN, &sgrowsiz, 0,
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"Amount to grow stack on a stack fault");
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SYSCTL_PROC(_kern, OID_AUTO, vm_guest, CTLFLAG_RD | CTLTYPE_STRING,
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NULL, 0, sysctl_kern_vm_guest, "A",
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"Virtual machine guest detected? (none|generic|xen)");
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/*
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* These have to be allocated somewhere; allocating
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* them here forces loader errors if this file is omitted
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* (if they've been externed everywhere else; hah!).
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*/
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struct buf *swbuf;
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/*
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* The elements of this array are ordered based upon the values of the
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* corresponding enum VM_GUEST members.
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*/
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static const char *const vm_guest_sysctl_names[] = {
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"none",
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"generic",
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"xen",
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NULL
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};
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#ifndef XEN
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static const char *const vm_bnames[] = {
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"QEMU", /* QEMU */
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"Plex86", /* Plex86 */
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"Bochs", /* Bochs */
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"Xen", /* Xen */
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"BHYVE", /* bhyve */
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"Seabios", /* KVM */
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NULL
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};
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static const char *const vm_pnames[] = {
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"VMware Virtual Platform", /* VMWare VM */
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"Virtual Machine", /* Microsoft VirtualPC */
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"VirtualBox", /* Sun xVM VirtualBox */
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"Parallels Virtual Platform", /* Parallels VM */
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"KVM", /* KVM */
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NULL
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};
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/*
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* Detect known Virtual Machine hosts by inspecting the emulated BIOS.
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*/
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static enum VM_GUEST
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detect_virtual(void)
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{
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char *sysenv;
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int i;
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sysenv = getenv("smbios.bios.vendor");
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if (sysenv != NULL) {
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for (i = 0; vm_bnames[i] != NULL; i++)
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if (strcmp(sysenv, vm_bnames[i]) == 0) {
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freeenv(sysenv);
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return (VM_GUEST_VM);
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}
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freeenv(sysenv);
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}
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sysenv = getenv("smbios.system.product");
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if (sysenv != NULL) {
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for (i = 0; vm_pnames[i] != NULL; i++)
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if (strcmp(sysenv, vm_pnames[i]) == 0) {
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freeenv(sysenv);
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return (VM_GUEST_VM);
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}
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freeenv(sysenv);
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}
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return (VM_GUEST_NO);
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}
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#endif
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/*
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* Boot time overrides that are not scaled against main memory
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*/
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void
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init_param1(void)
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{
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#ifndef XEN
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vm_guest = detect_virtual();
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#else
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vm_guest = VM_GUEST_XEN;
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#endif
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hz = -1;
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TUNABLE_INT_FETCH("kern.hz", &hz);
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if (hz == -1)
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hz = vm_guest > VM_GUEST_NO ? HZ_VM : HZ;
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tick = 1000000 / hz;
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tick_sbt = SBT_1S / hz;
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tick_bt = sbttobt(tick_sbt);
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#ifdef VM_SWZONE_SIZE_MAX
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maxswzone = VM_SWZONE_SIZE_MAX;
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#endif
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TUNABLE_LONG_FETCH("kern.maxswzone", &maxswzone);
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#ifdef VM_BCACHE_SIZE_MAX
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maxbcache = VM_BCACHE_SIZE_MAX;
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#endif
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TUNABLE_LONG_FETCH("kern.maxbcache", &maxbcache);
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msgbufsize = MSGBUF_SIZE;
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TUNABLE_INT_FETCH("kern.msgbufsize", &msgbufsize);
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maxtsiz = MAXTSIZ;
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TUNABLE_ULONG_FETCH("kern.maxtsiz", &maxtsiz);
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dfldsiz = DFLDSIZ;
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TUNABLE_ULONG_FETCH("kern.dfldsiz", &dfldsiz);
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maxdsiz = MAXDSIZ;
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TUNABLE_ULONG_FETCH("kern.maxdsiz", &maxdsiz);
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dflssiz = DFLSSIZ;
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TUNABLE_ULONG_FETCH("kern.dflssiz", &dflssiz);
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maxssiz = MAXSSIZ;
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TUNABLE_ULONG_FETCH("kern.maxssiz", &maxssiz);
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sgrowsiz = SGROWSIZ;
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TUNABLE_ULONG_FETCH("kern.sgrowsiz", &sgrowsiz);
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/*
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* Let the administrator set {NGROUPS_MAX}, but disallow values
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* less than NGROUPS_MAX which would violate POSIX.1-2008 or
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* greater than INT_MAX-1 which would result in overflow.
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*/
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ngroups_max = NGROUPS_MAX;
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TUNABLE_INT_FETCH("kern.ngroups", &ngroups_max);
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if (ngroups_max < NGROUPS_MAX)
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ngroups_max = NGROUPS_MAX;
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/*
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* Only allow to lower the maximal pid.
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* Prevent setting up a non-bootable system if pid_max is too low.
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*/
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TUNABLE_INT_FETCH("kern.pid_max", &pid_max);
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if (pid_max > PID_MAX)
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pid_max = PID_MAX;
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else if (pid_max < 300)
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pid_max = 300;
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TUNABLE_INT_FETCH("vfs.unmapped_buf_allowed", &unmapped_buf_allowed);
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}
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/*
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* Boot time overrides that are scaled against main memory
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*/
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void
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init_param2(long physpages)
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{
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/* Base parameters */
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maxusers = MAXUSERS;
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TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
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if (maxusers == 0) {
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maxusers = physpages / (2 * 1024 * 1024 / PAGE_SIZE);
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if (maxusers < 32)
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maxusers = 32;
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#ifdef VM_MAX_AUTOTUNE_MAXUSERS
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if (maxusers > VM_MAX_AUTOTUNE_MAXUSERS)
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maxusers = VM_MAX_AUTOTUNE_MAXUSERS;
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#endif
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/*
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* Scales down the function in which maxusers grows once
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* we hit 384.
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*/
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if (maxusers > 384)
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maxusers = 384 + ((maxusers - 384) / 8);
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}
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/*
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* The following can be overridden after boot via sysctl. Note:
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* unless overriden, these macros are ultimately based on maxusers.
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* Limit maxproc so that kmap entries cannot be exhausted by
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* processes.
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*/
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maxproc = NPROC;
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TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
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if (maxproc > (physpages / 12))
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maxproc = physpages / 12;
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maxprocperuid = (maxproc * 9) / 10;
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/*
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* The default limit for maxfiles is 1/12 of the number of
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* physical page but not less than 16 times maxusers.
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* At most it can be 1/6 the number of physical pages.
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*/
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maxfiles = imax(MAXFILES, physpages / 8);
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TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
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if (maxfiles > (physpages / 4))
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maxfiles = physpages / 4;
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maxfilesperproc = (maxfiles / 10) * 9;
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/*
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* Cannot be changed after boot.
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*/
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nbuf = NBUF;
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TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
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TUNABLE_INT_FETCH("kern.bio_transient_maxcnt", &bio_transient_maxcnt);
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/*
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* The default for maxpipekva is min(1/64 of the kernel address space,
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* max(1/64 of main memory, 512KB)). See sys_pipe.c for more details.
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*/
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maxpipekva = (physpages / 64) * PAGE_SIZE;
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TUNABLE_LONG_FETCH("kern.ipc.maxpipekva", &maxpipekva);
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if (maxpipekva < 512 * 1024)
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maxpipekva = 512 * 1024;
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if (maxpipekva > (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) / 64)
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maxpipekva = (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) /
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64;
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}
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/*
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* Sysctl stringiying handler for kern.vm_guest.
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*/
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static int
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sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS)
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{
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return (SYSCTL_OUT(req, vm_guest_sysctl_names[vm_guest],
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strlen(vm_guest_sysctl_names[vm_guest])));
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}
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