Commit Graph

99 Commits

Author SHA1 Message Date
Mark Johnston
a9d6f1fe0a Remove some remaining references to VM_ALLOC_NOOBJ
Reviewed by:	alc, kib
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D32037
2021-10-19 21:22:56 -04:00
Mark Johnston
aabe13f145 uma: Introduce per-domain reclamation functions
Make it possible to reclaim items from a specific NUMA domain.

- Add uma_zone_reclaim_domain() and uma_reclaim_domain().
- Permit parallel reclamations.  Use a counter instead of a flag to
  synchronize with zone_dtor().
- Use the zone lock to protect cache_shrink() now that parallel reclaims
  can happen.
- Add a sysctl that can be used to trigger reclamation from a specific
  domain.

Currently the new KPIs are unused, so there should be no functional
change.

Reviewed by:	mav
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D29685
2021-04-14 13:03:34 -04:00
Mark Johnston
09c8cb717d uma: Add KASAN state transitions
- Add a UMA_ZONE_NOKASAN flag to indicate that items from a particular
  zone should not be sanitized.  This is applied implicitly for NOFREE
  and cache zones.
- Add KASAN call backs which get invoked:
  1) when a slab is imported into a keg
  2) when an item is allocated from a zone
  3) when an item is freed to a zone
  4) when a slab is freed back to the VM

  In state transitions 1 and 3, memory is poisoned so that accesses will
  trigger a panic.  In state transitions 2 and 4, memory is marked
  valid.
- Disable trashing if KASAN is enabled.  It just adds extra CPU overhead
  to catch problems that are detected by KASAN.

MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D29456
2021-04-13 17:42:21 -04:00
Mark Johnston
e574d407ae uma: Make uma_zone_set_maxcache() work better with small limits
The old implementation chose the largest bucket zone such that if the
per-CPU caches are fully populated, the total number of items cached is
no larger than the specified limit.  If no such zone existed, UMA would
not do any caching.

We can now use uz_bucket_size_max to set a precise limit on the number
of items in a zone's bucket, so the total size of per-CPU caches can be
bounded more easily.  Implement a new policy in uma_zone_set_maxcache():
choose a bucket size such that up to half of the limit can be cached in
per-CPU caches, with the rest going to the full bucket cache.  This
fixes a problem with the kstack_cache zone: the limit of 4 * mp_ncpus
items meant that the zone would not do any caching, defeating the whole
purpose of the zone.  That's because the smallest bucket size holds up
to 2 items and we may cache up to 3 full buckets per CPU, and
2 * 3 * mp_ncpus > 4 * mp_ncpus.

Reported by:	mjg
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D27168
2020-12-06 22:45:50 +00:00
Mark Johnston
f8b6c51538 uma: Enforce the use of uz_bucket_size_max in the free path
uz_bucket_size_max is the maximum permitted bucket size.  When filling a
new bucket to satisfy uma_zalloc(), the bucket is populated with at most
uz_bucket_size_max items.  The maximum number of entries in the bucket
may be larger.  When freeing items, however, we will fill per-CPPU
buckets up to their maximum number of entries, potentially exceeding
uz_bucket_size_max.  This makes it difficult to precisely limit the
number of items that may be cached in a zone.  For example, if one wants
to limit buckets to 1 entry for a particular zone, that's not possible
since the smallest bucket holds up to 2 entries.

Try to solve the problem by using uz_bucket_size_max to limit the number
of entries in a bucket.  Note that the ub_entries field is initialized
upon every bucket allocation.  Most zones are not affected since they do
not impose any specific limit on the maximum bucket size.

While here, remove the UMA_ZONE_MINBUCKET flag.  It was unused and we
now have uma_zone_set_maxcache() to control the zone's cache size more
precisely.

Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D27167
2020-12-06 22:45:39 +00:00
Mateusz Guzik
3a440a421d Add more per-cpu zones.
This covers powers of 2 up to 64.

Example pending user is ZFS.
2020-11-09 00:34:23 +00:00
Mateusz Guzik
2dee296a3d Rationalize per-cpu zones.
The 2 provided zones had inconsistent naming between each other
("int" and "64") and other allocator zones (which use bytes).

Follow malloc by naming them "pcpu-" + size in bytes.

This is a step towards replacing ad-hoc per-cpu zones with
general slabs.
2020-11-05 15:08:56 +00:00
Mateusz Guzik
c3aa3bf97c vm: clean up empty lines in .c and .h files 2020-09-01 21:20:45 +00:00
Mark Johnston
96ad26eefb Remove free_domain() and uma_zfree_domain().
These functions were introduced before UMA started ensuring that freed
memory gets placed in domain-local caches.  They no longer serve any
purpose since UMA now provides their functionality by default.  Remove
them to simplyify the kernel memory allocator interfaces a bit.

Reviewed by:	cem, kib
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D25937
2020-08-04 13:58:36 +00:00
Jeff Roberson
c8b0a88b8d Clarify some language. Favor primary where both master and primary were
used in conjunction with secondary.
2020-06-20 20:21:04 +00:00
Mark Johnston
0464f16e91 Constify uma_zcache_create() and uma_zsecond_create()'s "name" argument.
It is already internally handled as a pointer to a const string, in
particular by uma_zcreate().

Fix indentation while here.

MFC after:	1 week
2020-02-22 17:44:28 +00:00
Jeff Roberson
ed581bf68f Add a simple accessor that returns the bytes of memory consumed by a zone. 2020-02-17 01:59:55 +00:00
Ryan Libby
bae55c4aec uma: remove UMA_ZFLAG_CACHEONLY flag
UMA_ZFLAG_CACHEONLY was essentially the same thing as UMA_ZONE_VM, but
with a more confusing name.  Remove the flag, make UMA_ZONE_VM an
inherit flag, and replace all references.

Reviewed by:	markj
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D23516
2020-02-06 08:32:25 +00:00
Ryan Libby
ec0d828071 uma: add UMA_ZONE_CONTIG, and a default contig_alloc
For now, copy the mbuf allocator.

Reviewed by:	jeff, markj (previous version)
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D23237
2020-02-04 22:40:11 +00:00
Jeff Roberson
d4665eaa66 Implement a safe memory reclamation feature that is tightly coupled with UMA.
This is in the same family of algorithms as Epoch/QSBR/RCU/PARSEC but is
a unique algorithm.  This has 3x the performance of epoch in a write heavy
workload with less than half of the read side cost.  The memory overhead
is significantly lessened by limiting the free-to-use latency.  A synthetic
test uses 1/20th of the memory vs Epoch.  There is significant further
discussion in the comments and code review.

This code should be considered experimental.  I will write a man page after
it has settled.  After further validation the VM will begin using this
feature to permit lockless page lookups.

Both markj and cperciva tested on arm64 at large core counts to verify
fences on weaker ordering architectures.  I will commit a stress testing
tool in a follow-up.

Reviewed by:	mmacy, markj, rlibby, hselasky
Discussed with:	sbahara
Differential Revision:	https://reviews.freebsd.org/D22586
2020-01-31 00:49:51 +00:00
Ryan Libby
9b8db4d0a0 uma: split slabzone into two sizes
By allowing more items per slab, we can improve memory efficiency for
small allocs.  If we were just to increase the bitmap size of the
slabzone, we would then waste slabzone memory.  So, split slabzone into
two zones, one especially for 8-byte allocs (512 per slab).  The
practical effect should be reduced memory usage for counter(9).

Reviewed by:	jeff, markj
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D23149
2020-01-14 02:14:15 +00:00
Ryan Libby
54c5ae804f uma: reorganize flags
- Garbage collect UMA_ZONE_PAGEABLE & UMA_ZONE_STATIC.
 - Move flag VTOSLAB from public to private.
 - Introduce public NOTPAGE flag and make HASH private.
 - Introduce public NOTOUCH flag and make OFFPAGE private.
 - Update man page.

The net effect of this should be to make the contract with clients more
clear.  Clients should choose constraints, UMA will figure out how to
implement them.  This also breaks the confusing double meaning of
OFFPAGE.

Reviewed by:	jeff, markj
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D23016
2020-01-09 02:03:03 +00:00
Jeff Roberson
dfe13344f5 UMA NUMA flag day. UMA_ZONE_NUMA was a source of confusion. Make the names
more consistent with other NUMA features as UMA_ZONE_FIRSTTOUCH and
UMA_ZONE_ROUNDROBIN.  The system will now pick a select a default depending
on kernel configuration.  API users need only specify one if they want to
override the default.

Remove the UMA_XDOMAIN and UMA_FIRSTTOUCH kernel options and key only off
of NUMA.  XDOMAIN is now fast enough in all cases to enable whenever NUMA
is.

Reviewed by:	markj
Discussed with:	rlibby
Differential Revision:	https://reviews.freebsd.org/D22831
2020-01-04 18:48:13 +00:00
Jeff Roberson
727c691857 Use a separate lock for the zone and keg. This provides concurrency
between populating buckets from the slab layer and fetching full buckets
from the zone layer.  Eliminate some nonsense locking patterns where
we lock to fetch a single variable.

Reviewed by:	markj
Differential Revision:	https://reviews.freebsd.org/D22828
2020-01-04 03:15:34 +00:00
Jeff Roberson
6d6a03d7a8 Handle large mallocs by going directly to kmem. Taking a detour through
UMA does not provide any additional value.

Reviewed by:	markj
Differential Revision:	https://reviews.freebsd.org/D22563
2019-11-29 03:14:10 +00:00
Mark Johnston
003cf08ba9 Revise the page cache size policy.
In r353734 the use of the page caches was limited to systems with a
relatively large amount of RAM per CPU.  This was to mitigate some
issues reported with the system not able to keep up with memory pressure
in cases where it had been able to do so prior to the addition of the
direct free pool cache.  This change re-enables those caches.

The change modifies uma_zone_set_maxcache(), which was introduced
specifically for the page cache zones.  Rather than using it to limit
only the full bucket cache, have it also set uz_count_max to provide an
upper bound on the per-CPU cache size that is consistent with the number
of items requested.  Remove its return value since it has no use.

Enable the page cache zones unconditionally, and limit them to 0.1% of
the domain's pages.  The limit can be overridden by the
vm.pgcache_zone_max tunable as before.

Change the item size parameter passed to uma_zcache_create() to the
correct size, and stop setting UMA_ZONE_MAXBUCKET.  This allows the page
cache buckets to be adaptively sized, like the rest of UMA's caches.
This also causes the initial bucket size to be small, so only systems
which benefit from large caches will get them.

Reviewed by:	gallatin, jeff
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D22393
2019-11-22 16:30:47 +00:00
Mateusz Guzik
a8c8e44bf0 vfs: manage mnt_ref with atomics
New primitive is introduced to denote sections can operate locklessly
on aspects of struct mount, but which can also be disabled if necessary.
This provides an opportunity to start scaling common case modifications
while providing stable state of the struct when facing unmount, write
suspendion or other events.

mnt_ref is the first counter to start being managed in this manner with
the intent to make it per-cpu.

Reviewed by:	kib, jeff
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D21425
2019-09-16 21:31:02 +00:00
Mark Johnston
08cfa56ea3 Extend uma_reclaim() to permit different reclamation targets.
The page daemon periodically invokes uma_reclaim() to reclaim cached
items from each zone when the system is under memory pressure.  This
is important since the size of these caches is unbounded by default.
However it also results in bursts of high latency when allocating from
heavily used zones as threads miss in the per-CPU caches and must
access the keg in order to allocate new items.

With r340405 we maintain an estimate of each zone's usage of its
(per-NUMA domain) cache of full buckets.  Start making use of this
estimate to avoid reclaiming the entire cache when under memory
pressure.  In particular, introduce TRIM, DRAIN and DRAIN_CPU
verbs for uma_reclaim() and uma_zone_reclaim().  When trimming, only
items in excess of the estimate are reclaimed.  Draining a zone
reclaims all of the cached full buckets (the previous behaviour of
uma_reclaim()), and may further drain the per-CPU caches in extreme
cases.

Now, when under memory pressure, the page daemon will trim zones
rather than draining them.  As a result, heavily used zones do not incur
bursts of bucket cache misses following reclamation, but large, unused
caches will be reclaimed as before.

Reviewed by:	jeff
Tested by:	pho (an earlier version)
MFC after:	2 months
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D16667
2019-09-01 22:22:43 +00:00
Mark Johnston
b48d4efe75 Handle UMA_ANYDOMAIN in kstack_import().
The kernel thread stack zone performs first-touch allocations by
default, and must handle the case where the local memory domain
is empty.  For most UMA zones this is handled in the keg layer,
but cache zones currently must implement a policy for this case.
Simply use a round-robin policy if UMA_ANYDOMAIN is passed.

Reported and tested by:	bcran
Reviewed by:	kib
Sponsored by:	The FreeBSD Foundation
2019-08-25 21:14:46 +00:00
Mateusz Guzik
5b596b9fa5 Remove the obsolete pcpu_zone_ptr zone.
It was only used by flowtable (removed in r321618).

Sponsored by:	The FreeBSD Foundation
2019-08-24 00:01:19 +00:00
Jeff Roberson
eda1b01647 Implement a MINBUCKET zone flag so we can use minimal caching on zones that
may be expensive to cache.

Reviewed by:	markj, kib
Sponsored by:		Netflix
Differential Revision:	https://reviews.freebsd.org/D20930
2019-08-06 23:04:59 +00:00
Jeff Roberson
c168508655 Add two new kernel options to control memory locality on NUMA hardware.
- UMA_XDOMAIN enables an additional per-cpu bucket for freed memory that
   was freed on a different domain from where it was allocated.  This is
   only used for UMA_ZONE_NUMA (first-touch) zones.
 - UMA_FIRSTTOUCH sets the default UMA policy to be first-touch for all
   zones.  This tries to maintain locality for kernel memory.

Reviewed by:	gallatin, alc, kib
Tested by:	pho, gallatin
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D20929
2019-08-06 21:50:34 +00:00
Gleb Smirnoff
bb15d1c778 o Move zone limit from keg level up to zone level. This means that now
two zones sharing a keg may have different limits. Now this is going
  to work:

  zone = uma_zcreate();
  uma_zone_set_max(zone, limit);
  zone2 = uma_zsecond_create(zone);
  uma_zone_set_max(zone2, limit2);

  Kegs no longer have uk_maxpages field, but zones have uz_items. When
  set, it may be rounded up to minimum possible CPU bucket cache size.
  For small limits bucket cache can also be reconfigured to be smaller.
  Counter uz_items is updated whenever items transition from keg to a
  bucket cache or directly to a consumer. If zone has uz_maxitems set and
  it is reached, then we are going to sleep.

o Since new limits don't play well with multi-keg zones, remove them. The
  idea of multi-keg zones was introduced exactly 10 years ago, and never
  have had a practical usage. In discussion with Jeff we came to a wild
  agreement that if we ever want to reintroduce the idea of a smart allocator
  that would be able to choose between two (or more) totally different
  backing stores, that choice should be made one level higher than UMA,
  e.g. in malloc(9) or in mget(), or whatever and choice should be controlled
  by the caller.

o Sleeping code is improved to account number of sleepers and wake them one
  by one, to avoid thundering herd problem.

o Flag UMA_ZONE_NOBUCKETCACHE removed, instead uma_zone_set_maxcache()
  KPI added. Having no bucket cache basically means setting maxcache to 0.

o Now with many fields added and many removed (no multi-keg zones!) make
  sure that struct uma_zone is perfectly aligned.

Reviewed by:	markj, jeff
Tested by:	pho
Differential Revision:	https://reviews.freebsd.org/D17773
2019-01-15 00:02:06 +00:00
Alan Cox
49bfa624ac Eliminate the arena parameter to kmem_free(). Implicitly this corrects an
error in the function hypercall_memfree(), where the wrong arena was being
passed to kmem_free().

Introduce a per-page flag, VPO_KMEM_EXEC, to mark physical pages that are
mapped in kmem with execute permissions.  Use this flag to determine which
arena the kmem virtual addresses are returned to.

Eliminate UMA_SLAB_KRWX.  The introduction of VPO_KMEM_EXEC makes it
redundant.

Update the nearby comment for UMA_SLAB_KERNEL.

Reviewed by:	kib, markj
Discussed with:	jeff
Approved by:	re (marius)
Differential Revision:	https://reviews.freebsd.org/D16845
2018-08-25 19:38:08 +00:00
Matt Macy
ab3059a8e7 Back pcpu zone with domain correct pages
- Change pcpu zone consumers to use a stride size of PAGE_SIZE.
  (defined as UMA_PCPU_ALLOC_SIZE to make future identification easier)

- Allocate page from the correct domain for a given cpu.

- Don't initialize pc_domain to non-zero value if NUMA is not defined
  There are some misconceptions surrounding this field. It is the
  _VM_ NUMA domain and should only ever correspond to valid domain
  values as understood by the VM.

The former slab size of sizeof(struct pcpu) was somewhat arbitrary.
The new value is PAGE_SIZE because that's the smallest granularity
which the VM can allocate a slab for a given domain. If you have
fewer than PAGE_SIZE/8 counters on your system there will be some
memory wasted, but this is obviously something where you want the
cache line to be coming from the correct domain.

Reviewed by: jeff
Sponsored by: Limelight Networks
Differential Revision:  https://reviews.freebsd.org/D15933
2018-07-06 02:06:03 +00:00
Jonathan T. Looney
0766f278d8 Make UMA and malloc(9) return non-executable memory in most cases.
Most kernel memory that is allocated after boot does not need to be
executable.  There are a few exceptions.  For example, kernel modules
do need executable memory, but they don't use UMA or malloc(9).  The
BPF JIT compiler also needs executable memory and did use malloc(9)
until r317072.

(Note that a side effect of r316767 was that the "small allocation"
path in UMA on amd64 already returned non-executable memory.  This
meant that some calls to malloc(9) or the UMA zone(9) allocator could
return executable memory, while others could return non-executable
memory.  This change makes the behavior consistent.)

This change makes malloc(9) return non-executable memory unless the new
M_EXEC flag is specified.  After this change, the UMA zone(9) allocator
will always return non-executable memory, and a KASSERT will catch
attempts to use the M_EXEC flag to allocate executable memory using
uma_zalloc() or its variants.

Allocations that do need executable memory have various choices.  They
may use the M_EXEC flag to malloc(9), or they may use a different VM
interfact to obtain executable pages.

Now that malloc(9) again allows executable allocations, this change also
reverts most of r317072.

PR:		228927
Reviewed by:	alc, kib, markj, jhb (previous version)
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D15691
2018-06-13 17:04:41 +00:00
Mateusz Guzik
4e180881ae uma: implement provisional api for per-cpu zones
Per-cpu zone allocations are very rarely done compared to regular zones.
The intent is to avoid pessimizing the latter case with per-cpu specific
code.

In particular contrary to the claim in r334824, M_ZERO is sometimes being
used for such zones. But the zeroing method is completely different and
braching on it in the fast path for regular zones is a waste of time.
2018-06-08 21:40:03 +00:00
Mark Johnston
7e28037a09 Add a UMA zone flag to disable the use of buckets.
This allows the creation of zones which don't do any caching in front of
the keg. If the zone is a cache zone, this means that UMA will not
attempt any memory allocations when allocating an item from the backend.
This is intended for use after a panic by netdump, but likely has other
applications.

Reviewed by:	kib
MFC after:	2 weeks
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D15184
2018-04-24 20:05:45 +00:00
Jeff Roberson
e8bb2dc7c9 Add the flag ZONE_NOBUCKETCACHE. This flag instructions UMA not to keep
a cache of fully populated buckets.  This will be used in a follow-on
commit.

The flag idea was originally from markj.

Reviewed by:	markj, kib
Tested by:	pho
Sponsored by:	Netflix, Dell/EMC Isilon
2018-04-01 04:47:05 +00:00
Gleb Smirnoff
f4bef67c9c Followup on r302393 by cperciva, improving calculation of boot pages required
for UMA startup.

o Introduce another stage of UMA startup, which is entered after
  vm_page_startup() finishes. After this stage we don't yet enable buckets,
  but we can ask VM for pages. Rename stages to meaningful names while here.
  New list of stages: BOOT_COLD, BOOT_STRAPPED, BOOT_PAGEALLOC, BOOT_BUCKETS,
  BOOT_RUNNING.
  Enabling page alloc earlier allows us to dramatically reduce number of
  boot pages required. What is more important number of zones becomes
  consistent across different machines, as no MD allocations are done before
  the BOOT_PAGEALLOC stage. Now only UMA internal zones actually need to use
  startup_alloc(), however that may change, so vm_page_startup() provides
  its need for early zones as argument.
o Introduce uma_startup_count() function, to avoid code duplication. The
  functions calculates sizes of zones zone and kegs zone, and calculates how
  many pages UMA will need to bootstrap.
  It counts not only of zone structures, but also of kegs, slabs and hashes.
o Hide uma_startup_foo() declarations from public file.
o Provide several DIAGNOSTIC printfs on boot_pages usage.
o Bugfix: when calculating zone of zones size use (mp_maxid + 1) instead of
  mp_ncpus. Use resulting number not only in the size argument to zone_ctor()
  but also as args.size.

Reviewed by:		imp, gallatin (earlier version)
Differential Revision:	https://reviews.freebsd.org/D14054
2018-02-06 04:16:00 +00:00
Jeff Roberson
ab3185d15e Implement NUMA support in uma(9) and malloc(9). Allocations from specific
domains can be done by the _domain() API variants.  UMA also supports a
first-touch policy via the NUMA zone flag.

The slab layer is now segregated by VM domains and is precise.  It handles
iteration for round-robin directly.  The per-cpu cache layer remains
a mix of domains according to where memory is allocated and freed.  Well
behaved clients can achieve perfect locality with no performance penalty.

The direct domain allocation functions have to visit the slab layer and
so require per-zone locks which come at some expense.

Reviewed by:	Attilio (a slightly older version)
Tested by:	pho
Sponsored by:	Netflix, Dell/EMC Isilon
2018-01-12 23:25:05 +00:00
Jeff Roberson
ad5b0f5b51 Fix arc after r326347 broke various memory limit queries. Use UMA features
rather than kmem arena size to determine available memory.

Initialize the UMA limit to LONG_MAX to avoid spurious wakeups on boot before
the real limit is set.

PR:		224330 (partial), 224080
Reviewed by:	markj, avg
Sponsored by:	Netflix / Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D13494
2018-01-02 04:35:56 +00:00
Jeff Roberson
2e47807c21 Eliminate kmem_arena and kmem_object in preparation for further NUMA commits.
The arena argument to kmem_*() is now only used in an assert.  A follow-up
commit will remove the argument altogether before we freeze the API for the
next release.

This replaces the hard limit on kmem size with a soft limit imposed by UMA.  When
the soft limit is exceeded we periodically wakeup the UMA reclaim thread to
attempt to shrink KVA.  On 32bit architectures this should behave much more
gracefully as we exhaust KVA.  On 64bit the limits are likely never hit.

Reviewed by:	markj, kib (some objections)
Discussed with:	alc
Tested by:	pho
Sponsored by:	Netflix / Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D13187
2017-11-28 23:40:54 +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
Jeff Roberson
8d6fbbb867 Replace manyinstances of VM_WAIT with blocking page allocation flags
similar to the kernel memory allocator.

This simplifies NUMA allocation because the domain will be known at wait
time and races between failure and sleeping are eliminated.  This also
reduces boilerplate code and simplifies callers.

A wait primitive is supplied for uma zones for similar reasons.  This
eliminates some non-specific VM_WAIT calls in favor of more explicit
sleeps that may be satisfied without new pages.

Reviewed by:	alc, kib, markj
Tested by:	pho
Sponsored by:	Netflix, Dell/EMC Isilon
2017-11-08 02:39:37 +00:00
John Baldwin
14c510c0cf Add UMA_ALIGNOF().
This is a wrapper around _Alignof() that sets the alignment for a zone
to the alignment required by a given type.  This allows the compiler to
determine the proper alignment rather than having the programmer try to
guess.

Discussed on:	arch@
MFC after:	1 week
Sponsored by:	DARPA / AFRL
2017-09-27 23:15:33 +00:00
Mark Johnston
e20ff1a4d4 Update a comment to reflect reality.
MFC after:	1 week
2017-03-13 18:45:25 +00:00
Nathan Whitehorn
96c85efb4b Replace a number of conflations of mp_ncpus and mp_maxid with either
mp_maxid or CPU_FOREACH() as appropriate. This fixes a number of places in
the kernel that assumed CPU IDs are dense in [0, mp_ncpus) and would try,
for example, to run tasks on CPUs that did not exist or to allocate too
few buffers on systems with sparse CPU IDs in which there are holes in the
range and mp_maxid > mp_ncpus. Such circumstances generally occur on
systems with SMT, but on which SMT is disabled. This patch restores system
operation at least on POWER8 systems configured in this way.

There are a number of other places in the kernel with potential problems
in these situations, but where sparse CPU IDs are not currently known
to occur, mostly in the ARM machine-dependent code. These will be fixed
in a follow-up commit after the stable/11 branch.

PR:		kern/210106
Reviewed by:	jhb
Approved by:	re (glebius)
2016-07-06 14:09:49 +00:00
Gleb Smirnoff
cfcae3f86f Remove UMA_ZONE_REFCNT feature, now unused.
Blessed by:	jeff
2016-03-01 00:33:32 +00:00
Gleb Smirnoff
e60b2fcbeb Redo r292484. Embed task(9) into zone, so that uz_maxaction is called
in a context that can sleep, allowing consumers of the KPI to run their
drain routines without any extra measures.

Discussed with:	jtl
2016-02-03 23:30:17 +00:00
Jonathan T. Looney
54503a13d8 Add a safety net to reclaim mbufs when one of the mbuf zones become
exhausted.

It is possible for a bug in the code (or, theoretically, even unusual
network conditions) to exhaust all possible mbufs or mbuf clusters.
When this occurs, things can grind to a halt fairly quickly. However,
we currently do not call mb_reclaim() unless the entire system is
experiencing a low-memory condition.

While it is best to try to prevent exhaustion of one of the mbuf zones,
it would also be useful to have a mechanism to attempt to recover from
these situations by freeing "expendable" mbufs.

This patch makes two changes:

a) The patch adds a generic API to the UMA zone allocator to set a
function that should be called when an allocation fails because the
zone limit has been reached. Because of the way this function can be
called, it really should do minimal work.

b) The patch uses this API to try to free mbufs when an allocation
fails from one of the mbuf zones because the zone limit has been
reached. The function schedules a callout to run mb_reclaim().

Differential Revision:	https://reviews.freebsd.org/D3864
Reviewed by:	gnn
Comments by:	rrs, glebius
MFC after:	2 weeks
Sponsored by:	Juniper Networks
2015-12-20 02:05:33 +00:00
Konstantin Belousov
44ec2b63c5 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
Ryan Stone
f2c2231e0c Fix integer truncation bug in malloc(9)
A couple of internal functions used by malloc(9) and uma truncated
a size_t down to an int.  This could cause any number of issues
(e.g. indefinite sleeps, memory corruption) if any kernel
subsystem tried to allocate 2GB or more through malloc.  zfs would
attempt such an allocation when run on a system with 2TB or more
of RAM.

Note to self: When this is MFCed, sparc64 needs the same fix.

Differential revision:	https://reviews.freebsd.org/D2106
Reviewed by:	kib
Reported by:	Michael Fuckner <michael@fuckner.net>
Tested by:	Michael Fuckner <michael@fuckner.net>
MFC after:	2 weeks
2015-04-01 12:42:26 +00:00
Gleb Smirnoff
49fef6a202 Create two public UMA_ZONE_PCPU zones: 64 bit sized and pointer sized.
Sponsored by:	Nginx, Inc.
2014-02-10 19:59:46 +00:00
Gleb Smirnoff
f947570e35 Style. 2014-02-10 19:51:15 +00:00