Commit Graph

88 Commits

Author SHA1 Message Date
Mateusz Guzik
75d6d57634 vm: remove seq.h inclusion made obsolete by NUMA rewrite
Sponsored by:	The FreeBSD Foundation
2019-02-27 22:42:29 +00:00
Konstantin Belousov
f2a496d667 MI VM: Make it possible to set size of superpage at boot instead of compile time.
In order to allow single kernel to use PAE pagetables on i386 if
hardware supports it, and fall back to classic two-level paging
structures if not, superpage code should be able to adopt to either 2M
or 4M superpages size.  There I make MI VM structures large enough to
track the biggest possible superpage, by allowing architecture to
define VM_NFREEORDER_MAX and VM_LEVEL_0_ORDER_MAX constants.
Corresponding VM_NFREEORDER and VM_LEVEL_0_ORDER symbols can be
defined as runtime values and must be less than the _MAX constants.
If architecture does not define _MAXs, it is assumed that _MAX ==
normal constant.

Reviewed by:	markj
Tested by:	pho (as part of the larger patch)
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D18853
2019-01-18 13:35:06 +00:00
Mark Johnston
87ab1a10b1 Initialize static domainsets regardless of whether an SRAT is present.
Reported by:	yuripv
X-MFC with:	r339452
Sponsored by:	The FreeBSD Foundation
2018-10-23 18:07:16 +00:00
Mark Johnston
b61f314290 Make it possible to disable NUMA support with a tunable.
This provides a chicken switch for anyone negatively impacted by
enabling NUMA in the amd64 GENERIC kernel configuration.  With
NUMA disabled at boot-time, information about the NUMA topology
is not exposed to the rest of the kernel, and all of physical
memory is viewed as coming from a single domain.

This method still has some performance overhead relative to disabling
NUMA support at compile time.

PR:		231460
Reviewed by:	alc, gallatin, kib
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D17439
2018-10-22 20:13:51 +00:00
Mark Johnston
662e7fa8d9 Create some global domainsets and refactor NUMA registration.
Pre-defined policies are useful when integrating the domainset(9)
policy machinery into various kernel memory allocators.

The refactoring will make it easier to add NUMA support for other
architectures.

No functional change intended.

Reviewed by:	alc, gallatin, jeff, kib
Tested by:	pho (part of a larger patch)
MFC after:	3 days
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D17416
2018-10-20 17:36:00 +00:00
Mark Johnston
463406ac4a Add more NUMA-specific low memory predicates.
Use these predicates instead of inline references to vm_min_domains.
Also add a global all_domains set, akin to all_cpus.

Reviewed by:	alc, jeff, kib
Approved by:	re (gjb)
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D17278
2018-09-24 19:24:17 +00:00
Alan Cox
72aebdd742 Recent changes have created, for the first time, physical memory segments
that can be coalesced.  To be clear, fragmentation of phys_avail[] is not
the cause.  This fragmentation of vm_phys_segs[] arises from the "special"
calls to vm_phys_add_seg(), in other words, not those that derive directly
from phys_avail[], but those that we create for the initial kernel page
table pages and now for the kernel and modules loaded at boot time.  Since
we sometimes iterate over the physical memory segments, coalescing these
segments at initialization time is a worthwhile change.

Reviewed by:	kib, markj
Approved by:	re (rgrimes)
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D16976
2018-09-02 18:29:38 +00:00
Warner Losh
67d33338c0 Rename VM_FREELIST_ISADMA to VM_FREELIST_LOWMEM.
There's no differene between VM_FREELIST_ISADMA and VM_FREELIST_LOWMEM
except for the default boundary (16MB on x86 and 256MB on MIPS, but
they are otherwise the same). We don't need both for any system we
support (there were some really old ARC systems that did have ISA/EISA
bus, but we never ran on them and they are too old to ever grow
support for).

Differential Review: https://reviews.freebsd.org/D16290
2018-07-27 18:34:20 +00:00
Alan Cox
370a338a7d Allow callers to vm_phys_split_pages() to specify whether insertion should
occur at the head or the tail of the page queues.
2018-07-05 02:08:57 +00:00
Alan Cox
7493904eca Introduce vm_phys_enq_range(), and call it in vm_phys_alloc_npages()
and vm_phys_alloc_seg_contig() instead of vm_phys_free_contig().  In
short, vm_phys_enq_range() is simpler and faster than the more general
vm_phys_free_contig(), and in the case of vm_phys_alloc_seg_contig(),
vm_phys_free_contig() was placing the excess physical pages at the
wrong end of the queues.

In collaboration with:	Doug Moore <dougm@rice.edu>
2018-07-02 17:18:46 +00:00
Alan Cox
9161b4de54 Three changes to vm_phys_alloc_seg_contig():
1. Optimize the order computation.

2. Update the pool for all of the chunks that are removed from the free
   page lists, and not just the first chunk.

3. Simplify the code for returning excess pages to the free page lists.

Reviewed by:	Doug Moore <dougm@rice.edu>
2018-06-29 04:08:14 +00:00
Alan Cox
32d81f21b9 Reflow one of the comments describing vm_phys_alloc_npages(). 2018-06-28 17:52:06 +00:00
Alan Cox
89ea39a727 Update the physical page selection strategy used by vm_page_import() so
that it does not cause rapid fragmentation of the free physical memory.

Reviewed by:	jeff, markj (an earlier version)
Differential Revision:	https://reviews.freebsd.org/D15976
2018-06-26 18:29:56 +00:00
Mark Johnston
5cd29d0f3c Improve VM page queue scalability.
Currently both the page lock and a page queue lock must be held in
order to enqueue, dequeue or requeue a page in a given page queue.
The queue locks are a scalability bottleneck in many workloads. This
change reduces page queue lock contention by batching queue operations.
To detangle the page and page queue locks, per-CPU batch queues are
used to reference pages with pending queue operations. The requested
operation is encoded in the page's aflags field with the page lock
held, after which the page is enqueued for a deferred batch operation.
Page queue scans are similarly optimized to minimize the amount of
work performed with a page queue lock held.

Reviewed by:	kib, jeff (previous versions)
Tested by:	pho
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D14893
2018-04-24 21:15:54 +00:00
Jeff Roberson
c33e3a642b Add a uma cache of free pages in the DEFAULT freepool. This gives us
per-cpu alloc and free of pages.  The cache is filled with as few trips
to the phys allocator as possible by the use of a new
vm_phys_alloc_npages() function which allocates as many as N pages.

This code was originally by markj with the import function rewritten by
me.

Reviewed by:	markj, kib
Tested by:	pho
Sponsored by:	Netflix, Dell/EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D14905
2018-04-01 04:50:05 +00:00
Jeff Roberson
cdfeced8ff Use read_mostly and alignment tags to eliminate or limit false sharing.
Reviewed by:	markj (Part of D14707)
Sponsored by:	Netflix, Dell/EMC Isilon
2018-03-22 19:06:50 +00:00
Konstantin Belousov
79e9552ebb Check for wrap-around in vm_phys_alloc_seg_contig().
It is possible to provide insane values for size in contigmalloc(9)
request, which usually not reaches the phys allocator due to failing
KVA allocation.  But with the forthcoming 4/4 i386, where 32bit
architecture has almost 4G KVA, contigmalloc(1G) is not unreasonable
outright and KVA might be available sometimes.

Then, the calculation of pa_end could wrap around, depending on the
physical address, and the checks in vm_phys_alloc_seg_contig() would
pass while the iteration in the loop after the 'done' label goes out
of the vm_page_array bounds.

Fix it by detecting the wrap.

Reported and tested by:	pho
Reviewed by:	alc, markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D14767
2018-03-20 16:17:55 +00:00
Jeff Roberson
e2068d0bcd Use per-domain locks for vm page queue free. Move paging control from
global to per-domain state.  Protect reservations with the free lock
from the domain that they belong to.  Refactor to make vm domains more
of a first class object.

Reviewed by:    markj, kib, gallatin
Tested by:      pho
Sponsored by:   Netflix, Dell/EMC Isilon
Differential Revision:  https://reviews.freebsd.org/D14000
2018-02-06 22:10:07 +00:00
Jeff Roberson
b6715dab8f Move VM_NUMA_ALLOC and DEVICE_NUMA under the single global config option NUMA.
Sponsored by:	Netflix, Dell/EMC Isilon
Discussed with:	jhb
2018-01-14 03:36:03 +00:00
Jeff Roberson
6f4acaf4c9 Add support for NUMA domains to bus dma tags. This causes all memory
allocated with a tag to come from the specified domain if it meets the
other constraints provided by the tag.  Automatically create a tag at
the root of each bus specifying the domain local to that bus if
available.

Reviewed by:	jhb, kib
Tested by:	pho
Sponsored by:	Netflix, Dell/EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D13545
2018-01-12 23:34:16 +00:00
Jeff Roberson
3f289c3fcf Implement 'domainset', a cpuset based NUMA policy mechanism. This allows
userspace to control NUMA policy administratively and programmatically.

Implement domainset based iterators in the page layer.

Remove the now legacy numa_* syscalls.

Cleanup some header polution created by having seq.h in proc.h.

Reviewed by:	markj, kib
Discussed with:	alc
Tested by:	pho
Sponsored by:	Netflix, Dell/EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D13403
2018-01-12 22:48:23 +00:00
Andrew Turner
5be9377857 Print the correct value when freelist is out of range.
Security:	:
Sponsored by:	DARPA, AFRL
2017-12-04 11:16:51 +00:00
Michael Zhilin
0db2102aaa [mips] [vm] restore translation of freelist to flind for page allocation
Commit r326346 moved domain iterators from physical layer to vm_page one,
but it also removed translation of freelist to flind for
vm_page_alloc_freelist() call. Before it expects VM_FREELIST_ parameter,
but after it expect freelist index.

On small WiFi boxes with few megabytes of RAM, there is only one freelist
VM_FREELIST_LOWMEM (1) and there is no VM_FREELIST_DEFAULT(0) (see file
sys/mips/include/vmparam.h). It results in freelist 1 with flind 0.

At first, this commit renames flind to freelist in vm_page_alloc_freelist
to avoid misunderstanding about input parameters. Then on physical layer it
restores translation for correct handling of freelist parameter.

Reported by:	landonf
Reviewed by:	jeff
Differential Revision:	https://reviews.freebsd.org/D13351
2017-12-04 08:08:55 +00:00
Jeff Roberson
ef435ae7de Move domain iterators into the page layer where domain selection should take
place.  This makes the majority of the phys layer explicitly domain specific.

Reviewed by:	markj, kib (some objections)
Discussed with:	alc
Tested by:	pho
Sponsored by:	Netflix & Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D13014
2017-11-28 23:18:35 +00:00
Mark Johnston
d2b677cef6 Avoid unnecessary lookups when initializing the vm_page array.
This gives a marginal improvement in the vm_page_array initialization
time. Also garbage-collect the now-unused vm_phys_paddr_to_segind().

Reviewed by:	alc, kib
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D13270
2017-11-27 17:46:38 +00:00
Pedro F. Giffuni
fe267a5590 sys: general adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.
2017-11-27 15:23:17 +00:00
Mark Johnston
b20bf182e6 Move vm_phys_init_page() to vm_page.c.
Suggested by:	kib
Reviewed by:	alc, kib
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D13250
2017-11-26 19:17:55 +00:00
Mark Johnston
830cb6b2b6 Remove unneeded initializations from vm_phys_init_page().
The page allocator always initializes the aflags and oflags fields.

Reviewed by:	alc, kib
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D13242
2017-11-26 19:16:45 +00:00
Mark Johnston
f93f7cf199 Speed up vm_page_array initialization.
We currently initialize the vm_page array in three passes: one to zero
the array, one to initialize the "order" field of each page (necessary
when inserting them into the vm_phys buddy allocator one-by-one), and
one to initialize the remaining non-zero fields and individually insert
each page into the allocator.

Merge the three passes into one following a suggestion from alc:
initialize vm_page fields in a single pass, and use vm_phys_free_contig()
to efficiently insert physical memory segments into the buddy allocator.
This reduces the initialization time to a third or a quarter of what it
was before on most systems that I tested.

Reviewed by:	alc, kib
MFC after:	3 weeks
Differential Revision:	https://reviews.freebsd.org/D12248
2017-09-07 21:43:39 +00:00
Edward Tomasz Napierala
a6b15641d6 Ifdef out the unused vm_rr_selectdomain().
MFC after:	2 weeks
Sponsored by:	DARPA, AFRL
2017-02-02 17:44:55 +00:00
Mark Johnston
dbbaf04f1e Remove support for idle page zeroing.
Idle page zeroing has been disabled by default on all architectures since
r170816 and has some bugs that make it seemingly unusable. Specifically,
the idle-priority pagezero thread exacerbates contention for the free page
lock, and yields the CPU without releasing it in non-preemptive kernels. The
pagezero thread also does not behave correctly when superpage reservations
are enabled: its target is a function of v_free_count, which includes
reserved-but-free pages, but it is only able to zero pages belonging to the
physical memory allocator.

Reviewed by:	alc, imp, kib
Differential Revision:	https://reviews.freebsd.org/D7714
2016-09-03 20:38:13 +00:00
Mark Johnston
fc85a6f0c4 Initialize page busy lock state in vm_phys_add_page().
MFC after:	1 week
2016-08-13 19:48:43 +00:00
Pedro F. Giffuni
d9c9c81c08 sys: use our roundup2/rounddown2() macros when param.h is available.
rounddown2 tends to produce longer lines than the original code
and when the code has a high indentation level it was not really
advantageous to do the replacement.

This tries to strike a balance between readability using the macros
and flexibility of having the expressions, so not everything is
converted.
2016-04-21 19:57:40 +00:00
John Baldwin
62d70a8174 Add more fine-grained kernel options for NUMA support.
VM_NUMA_ALLOC is used to enable use of domain-aware memory allocation in
the virtual memory system.  DEVICE_NUMA is used to enable affinity
reporting for devices such as bus_get_domain().

MAXMEMDOM must still be set to a value greater than for any NUMA support
to be effective.  Note that 'cpuset -gd' always works if MAXMEMDOM is
enabled and the system supports NUMA.

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D5782
2016-04-09 13:58:04 +00:00
Alan Cox
477bffbe4d A fix to r292469: Iterate over the physical segments in descending rather
than ascending order in vm_phys_alloc_contig() so that, for example, a
sequence of contigmalloc(low=0, high=4GB) calls doesn't exhaust the supply
of low physical memory resulting in a later contigmalloc(low=0, high=1MB)
failure.

Reported by:	cy
Tested by:	cy
Sponsored by:	EMC / Isilon Storage Division
2016-01-16 04:41:40 +00:00
Alan Cox
c869e67208 Introduce a new mechanism for relocating virtual pages to a new physical
address and use this mechanism when:

1. kmem_alloc_{attr,contig}() can't find suitable free pages in the physical
   memory allocator's free page lists.  This replaces the long-standing
   approach of scanning the inactive and inactive queues, converting clean
   pages into PG_CACHED pages and laundering dirty pages.  In contrast, the
   new mechanism does not use PG_CACHED pages nor does it trigger a large
   number of I/O operations.

2. on 32-bit MIPS processors, uma_small_alloc() and the pmap can't find
   free pages in the physical memory allocator's free page lists that are
   covered by the direct map.  Tested by: adrian

3. ttm_bo_global_init() and ttm_vm_page_alloc_dma32() can't find suitable
   free pages in the physical memory allocator's free page lists.

In the coming months, I expect that this new mechanism will be applied in
other places.  For example, balloon drivers should use relocation to
minimize fragmentation of the guest physical address space.

Make vm_phys_alloc_contig() a little smarter (and more efficient in some
cases).  Specifically, use vm_phys_segs[] earlier to avoid scanning free
page lists that can't possibly contain suitable pages.

Reviewed by:	kib, markj
Glanced at:	jhb
Discussed with:	jeff
Sponsored by:	EMC / Isilon Storage Division
Differential Revision:	https://reviews.freebsd.org/D4444
2015-12-19 18:42:50 +00:00
Adrian Chadd
6520495abc Add an initial NUMA affinity/policy configuration for threads and processes.
This is based on work done by jeff@ and jhb@, as well as the numa.diff
patch that has been circulating when someone asks for first-touch NUMA
on -10 or -11.

* Introduce a simple set of VM policy and iterator types.
* tie the policy types into the vm_phys path for now, mirroring how
  the initial first-touch allocation work was enabled.
* add syscalls to control changing thread and process defaults.
* add a global NUMA VM domain policy.
* implement a simple cascade policy order - if a thread policy exists, use it;
  if a process policy exists, use it; use the default policy.
* processes inherit policies from their parent processes, threads inherit
  policies from their parent threads.
* add a simple tool (numactl) to query and modify default thread/process
  policities.
* add documentation for the new syscalls, for numa and for numactl.
* re-enable first touch NUMA again by default, as now policies can be
  set in a variety of methods.

This is only relevant for very specific workloads.

This doesn't pretend to be a final NUMA solution.

The previous defaults in -HEAD (with MAXMEMDOM set) can be achieved by
'sysctl vm.default_policy=rr'.

This is only relevant if MAXMEMDOM is set to something other than 1.
Ie, if you're using GENERIC or a modified kernel with non-NUMA, then
this is a glorified no-op for you.

Thank you to Norse Corp for giving me access to rather large
(for FreeBSD!) NUMA machines in order to develop and verify this.

Thank you to Dell for providing me with dual socket sandybridge
and westmere v3 hardware to do NUMA development with.

Thank you to Scott Long at Netflix for providing me with access
to the two-socket, four-domain haswell v3 hardware.

Thank you to Peter Holm for running the stress testing suite
against the NUMA branch during various stages of development!

Tested:

* MIPS (regression testing; non-NUMA)
* i386 (regression testing; non-NUMA GENERIC)
* amd64 (regression testing; non-NUMA GENERIC)
* westmere, 2 socket (thankyou norse!)
* sandy bridge, 2 socket (thankyou dell!)
* ivy bridge, 2 socket (thankyou norse!)
* westmere-EX, 4 socket / 1TB RAM (thankyou norse!)
* haswell, 2 socket (thankyou norse!)
* haswell v3, 2 socket (thankyou dell)
* haswell v3, 2x18 core (thankyou scott long / netflix!)

* Peter Holm ran a stress test suite on this work and found one
  issue, but has not been able to verify it (it doesn't look NUMA
  related, and he only saw it once over many testing runs.)

* I've tested bhyve instances running in fixed NUMA domains and cpusets;
  all seems to work correctly.

Verified:

* intel-pcm - pcm-numa.x and pcm-memory.x, whilst selecting different
  NUMA policies for processes under test.

Review:

This was reviewed through phabricator (https://reviews.freebsd.org/D2559)
as well as privately and via emails to freebsd-arch@.  The git history
with specific attributes is available at https://github.com/erikarn/freebsd/
in the NUMA branch (https://github.com/erikarn/freebsd/compare/local/adrian_numa_policy).

This has been reviewed by a number of people (stas, rpaulo, kib, ngie,
wblock) but not achieved a clear consensus.  My hope is that with further
exposure and testing more functionality can be implemented and evaluated.

Notes:

* The VM doesn't handle unbalanced domains very well, and if you have an overly
  unbalanced memory setup whilst under high memory pressure, VM page allocation
  may fail leading to a kernel panic.  This was a problem in the past, but it's
  much more easily triggered now with these tools.

* This work only controls the path through vm_phys; it doesn't yet strongly/predictably
  affect contigmalloc, KVA placement, UMA, etc.  So, driver placement of memory
  isn't really guaranteed in any way.  That's next on my plate.

Sponsored by:	Norse Corp, Inc.; Dell
2015-07-11 15:21:37 +00:00
Adrian Chadd
415d7ccab2 Add initial memory locality cost awareness to the VM, and include
a basic ACPI SLIT table parser.

For now this just exports the map via sysctl; it'll eventually be useful
to userland when there's more useful NUMA support in -HEAD.

* Add an optional mem_locality map;
* add a mapping function taking from/to domain and returning the
  relative cost, or -1 if it's not available;
* Add a very basic SLIT parser to x86 ACPI.

Differential Revision:	https://reviews.freebsd.org/D2460
Reviewed by:	rpaulo, stas, jhb
Sponsored by:	Norse Corp, Inc (hardware, coding); Dell (hardware)
2015-05-08 00:56:56 +00:00
Ian Lepore
ed9dd64b8c Revert r279932; this is going to be fixed in the sbuf code instead.
PR:		195668
2015-03-14 13:00:37 +00:00
Ian Lepore
f3b9fcf251 Nullterminate strings returned via sysctl.
PR:		195668
2015-03-12 18:06:30 +00:00
Alan Cox
d866a563d4 The physical memory allocator supports the use of distinct free lists for
managing pages from different address ranges.  Generally speaking, this
feature is used to increase the likelihood that physical pages are
available that can meet special DMA requirements or can be accessed through
a limited-coverage direct mapping (e.g., MIPS).  However, prior to this
change, the configuration of the free lists was static, i.e., it was
determined at compile time.  Consequentally, free lists could be created
for address ranges that held no actual pages, for example, on 32-bit MIPS-
based systems with 512 MB or less of physical memory.  This change makes
the creation of the free lists dynamic, i.e., it is based on the available
physical memory at boot time.

On 64-bit x86-based systems with 64 GB or more of physical memory, create
free lists for managing pages with physical addresses below 4 GB.  This
change is to address reported problems with initializing devices that
require the allocation of physical pages below 4 GB on some systems with
128 GB or more of physical memory.

PR:		185727
Differential Revision:	https://reviews.freebsd.org/D1274
Reviewed by:	jhb, kib
MFC after:	3 weeks
Sponsored by:	EMC / Isilon Storage Division
2014-12-31 00:54:38 +00:00
Alan Cox
271f0f1219 Enable the use of VM_PHYSSEG_SPARSE on amd64 and i386, making it the default
on i386 PAE.  Previously, VM_PHYSSEG_SPARSE could not be used on amd64 and
i386 because vm_page_startup() would not create vm_page structures for the
kernel page table pages allocated during pmap_bootstrap() but those vm_page
structures are needed when the kernel attempts to promote the corresponding
kernel virtual addresses to superpage mappings.  To address this problem, a
new public function, vm_phys_add_seg(), is introduced and vm_phys_init() is
updated to reflect the creation of vm_phys_seg structures by calls to
vm_phys_add_seg().

Discussed with:	Svatopluk Kraus
MFC after:	3 weeks
Sponsored by:	EMC / Isilon Storage Division
2014-11-15 23:40:44 +00:00
Roger Pau Monné
5ebe728d53 vm_phys: improve robustness of fictitious ranges
With the current implementation of managed fictitious ranges when
also using VM_PHYSSEG_DENSE, a user could try to register a
fictitious range that starts inside of vm_page_array, but then
overrruns it (because the end of the fictitious range is greater than
vm_page_array_size + first_page). This would result in PHYS_TO_VM_PAGE
returning unallocated pages from past the end of vm_page_array. The
same could happen if a user tried to register a segment that starts
outside of vm_page_array but ends inside of it.

In order to fix this, allow vm_phys_fictitious_{reg/unreg}_range to
use a set of pages from vm_page_array, and allocate the rest.

Sponsored by: Citrix Systems R&D
Reviewed by: kib, alc

vm/vm_phys.c:
 - Allow registering/unregistering fictitious ranges that overrun
   vm_page_array.
2014-08-05 10:29:01 +00:00
Roger Pau Monné
38d6b2dcb2 vm_phys: remove limitation on number of fictitious regions
The number of vm fictitious regions was limited to 8 by default, but
Xen will make heavy usage of those kind of regions in order to map
memory from foreign domains, so instead of increasing the default
number, change the implementation to use a red-black tree to track vm
fictitious ranges.

The public interface remains the same.

Sponsored by: Citrix Systems R&D
Reviewed by: kib, alc
Approved by: gibbs

vm/vm_phys.c:
 - Replace the vm fictitious static array with a red-black tree.
 - Use a rwlock instead of a mutex, since now we also need to take the
   lock in vm_phys_fictitious_to_vm_page, and it can be shared.
2014-07-09 08:12:58 +00:00
Konstantin Belousov
a17937bdd0 For the VM_PHYSSEG_DENSE case, checking the requested range to fall
into the area backed by vm_page_array wrongly compared end with
vm_page_array_size.  It should be adjusted by first_page index to be
correct.

Also, the corner and incorrect case of the requested range extending
after the end of the vm_page_array was incorrectly handled by
allocating the segment.

Fix the comparision for the end of range and return EINVAL if the end
extends beyond vm_page_array.

Discussed with:	royger
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2014-04-29 18:42:37 +00:00
Bryan Drewery
44f1c91610 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
Alan Cox
000fb817d8 Since the introduction of the popmap to reservations in r259999, there is
no longer any need for the page's PG_CACHED and PG_FREE flags to be set and
cleared while the free page queues lock is held.  Thus, vm_page_alloc(),
vm_page_alloc_contig(), and vm_page_alloc_freelist() can wait until after
the free page queues lock is released to clear the page's flags.  Moreover,
the PG_FREE flag can be retired.  Now that the reservation system no longer
uses it, its only uses are in a few assertions.  Eliminating these
assertions is no real loss.  Other assertions catch the same types of
misbehavior, like doubly freeing a page (see r260032) or dirtying a free
page (free pages are invalid and only valid pages can be dirtied).

Eliminate an unneeded variable from vm_page_alloc_contig().

Sponsored by:	EMC / Isilon Storage Division
2013-12-31 18:25:15 +00:00
Alan Cox
eb2f42fbb0 Tidy up the output of "sysctl vm.phys_free".
Approved by:	re (glebius)
Sponsored by:	EMC / Isilon Storage Division
2013-10-10 16:11:45 +00:00
Konstantin Belousov
c325e866f4 Different consumers of the struct vm_page abuse pageq member to keep
additional information, when the page is guaranteed to not belong to a
paging queue.  Usually, this results in a lot of type casts which make
reasoning about the code correctness harder.

Sometimes m->object is used instead of pageq, which could cause real
and confusing bugs if non-NULL m->object is leaked.  See r141955 and
r253140 for examples.

Change the pageq member into a union containing explicitly-typed
members.  Use them instead of type-punning or abusing m->object in x86
pmaps, uma and vm_page_alloc_contig().

Requested and reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
2013-08-10 17:36:42 +00:00
Attilio Rao
c7aebda8a1 The soft and hard busy mechanism rely on the vm object lock to work.
Unify the 2 concept into a real, minimal, sxlock where the shared
acquisition represent the soft busy and the exclusive acquisition
represent the hard busy.
The old VPO_WANTED mechanism becames the hard-path for this new lock
and it becomes per-page rather than per-object.
The vm_object lock becames an interlock for this functionality:
it can be held in both read or write mode.
However, if the vm_object lock is held in read mode while acquiring
or releasing the busy state, the thread owner cannot make any
assumption on the busy state unless it is also busying it.

Also:
- Add a new flag to directly shared busy pages while vm_page_alloc
  and vm_page_grab are being executed.  This will be very helpful
  once these functions happen under a read object lock.
- Move the swapping sleep into its own per-object flag

The KPI is heavilly changed this is why the version is bumped.
It is very likely that some VM ports users will need to change
their own code.

Sponsored by:	EMC / Isilon storage division
Discussed with:	alc
Reviewed by:	jeff, kib
Tested by:	gavin, bapt (older version)
Tested by:	pho, scottl
2013-08-09 11:11:11 +00:00