Commit Graph

47 Commits

Author SHA1 Message Date
mdf
1bc1b805d7 Const-ify the zone name argument to uma_zcreate(9).
MFC after:	3 days
2012-10-26 17:51:05 +00:00
alc
a899800e2a 1. Prior to r214782, UMA did not support multipage allocations before
uma_startup2() was called.  Thus, setting the variable "booted" to true in
uma_startup() was ok on machines with UMA_MD_SMALL_ALLOC defined, because
any allocations made after uma_startup() but before uma_startup2() could be
satisfied by uma_small_alloc().  Now, however, some multipage allocations
are necessary before uma_startup2() just to allocate zone structures on
machines with a large number of processors.  Thus, a Boolean can no longer
effectively describe the state of the UMA allocator.  Instead, make "booted"
have three values to describe how far initialization has progressed.  This
allows multipage allocations to continue using startup_alloc() until
uma_startup2(), but single-page allocations may begin using
uma_small_alloc() after uma_startup().

2. With the aforementioned change, only a modest increase in boot pages is
necessary to boot UMA on a large number of processors.

3. Retire UMA_MD_SMALL_ALLOC_NEEDS_VM.  It has only been used between
r182028 and r204128.

Reviewed by:	attilio [1], nwhitehorn [3]
Tested by:	sbruno
2011-05-21 17:43:43 +00:00
alc
3c08fd7d05 Fix spelling errors. 2011-05-20 17:28:00 +00:00
sbruno
3571902304 Add a new column to the output of vmstat -z to indicate the number
of times the system was forced to sleep when requesting a new allocation.

Expand the debugger hook, db_show_uma, to display these results as well.

This has proven to be very useful in out of memory situations when
it is not known why systems have become sluggish or fail in odd ways.

Reviewed by:	rwatson alc
Approved by:	scottl (mentor) peter
Obtained from:	Yahoo Inc.
2010-06-15 19:28:37 +00:00
kmacy
122090fb7e - enable alignment on amd64 only
- only align pcpu caches and the volatile portion of uma_zone
2010-03-22 22:39:32 +00:00
kmacy
377858b3ae turn 205266 in to a no-op until the problem can be properly diagnosed 2010-03-18 20:30:25 +00:00
kmacy
4e6ab892f5 Cache line align various structures and move volatile counters to
not share a cache line with (mostly) immutable state

Reviewed by:	jeff@
MFC after:	7 days
2010-03-17 21:18:28 +00:00
antoine
646097b80a Remove trailing ";" in UMA_HASH_INSERT and UMA_HASH_REMOVE macros.
MFC after:	1 month
2009-12-05 17:45:56 +00:00
jeff
69d1bd8670 - 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
rwatson
e8ccc2cbbd Update stale comment on protecting UMA per-CPU caches: we now use
critical sections rather than mutexes.
2007-05-09 22:53:34 +00:00
rwatson
65053d65ad Wrap inlines in uma_int.h in #ifdef _KERNEL so that uma_int.h can be
used from memstat_uma.c for the purposes of kvm access without lots
of additional unsafe includes.

MFC after:	3 days
2005-08-04 10:03:53 +00:00
rwatson
4ead3022dd Improve canonicalization of copyrights. Order copyrights by order of
assertion (jeff, bmilekic, rwatson).

Suggested ages ago by:	bde
MFC after:		1 week
2005-07-16 09:51:52 +00:00
silby
24f7a1c3d6 Increase the flags field for kegs from a 16 to a 32 bit value;
we have exhausted all 16 flags.
2005-07-16 02:23:41 +00:00
rwatson
87bbce9e08 Track UMA(9) allocation failures by zone, and export via sysctl.
Requested by:	victor cruceru <victor dot cruceru at gmail dot com>
MFC after:	1 week
2005-07-15 23:34:39 +00:00
rwatson
83343a94ec Introduce a new sysctl, vm.zone_stats, which exports UMA(9) allocator
statistics via a binary structure stream:

- Add structure 'uma_stream_header', which defines a stream version,
  definition of MAXCPUs used in the stream, and the number of zone
  records in the stream.

- Add structure 'uma_type_header', which defines the name, alignment,
  size, resource allocation limits, current pages allocated, preferred
  bucket size, and central zone + keg statistics.

- Add structure 'uma_percpu_stat', which, for each per-CPU cache,
  includes the number of allocations and frees, as well as the number
  of free items in the cache.

- 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 uma_percpu_stat structures holding
  per-CPU allocation information.  Typical values of MAXCPU 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, also export the number of UMA zones as a sysctl
vm.uma_count, in order to assist in sizing user swpace buffers to
receive the stream.

A follow-up commit of libmemstat(3), a library to monitor kernel memory
allocation, will occur in the next few days.  This change directly
supports converting netstat(1)'s "-mb" mode to using UMA-sourced stats
rather than separately maintained mbuf allocator statistics.

MFC after:	1 week
2005-07-14 16:35:13 +00:00
rwatson
c24543fa50 In addition to tracking allocs in the zone, also track frees. Add
a zone free counter, as well as a cache free counter.

MFC after:	1 week
2005-07-14 16:17:21 +00:00
alc
67602b23a9 Increase UMA_BOOT_PAGES to prevent a crash during initialization. See
http://docs.FreeBSD.org/cgi/mid.cgi?42AD8270.8060906 for a detailed
description of the crash.

Reported by: Eric Anderson
Approved by: re (scottl)
MFC after: 3 days
2005-06-16 17:06:34 +00:00
rwatson
bb1e0b257a Modify UMA to use critical sections to protect per-CPU caches, rather than
mutexes, which offers lower overhead on both UP and SMP.  When allocating
from or freeing to the per-cpu cache, without INVARIANTS enabled, we now
no longer perform any mutex operations, which offers a 1%-3% performance
improvement in a variety of micro-benchmarks.  We rely on critical
sections to prevent (a) preemption resulting in reentrant access to UMA on
a single CPU, and (b) migration of the thread during access.  In the event
we need to go back to the zone for a new bucket, we release the critical
section to acquire the global zone mutex, and must re-acquire the critical
section and re-evaluate which cache we are accessing in case migration has
occured, or circumstances have changed in the current cache.

Per-CPU cache statistics are now gathered lock-free by the sysctl, which
can result in small races in statistics reporting for caches.

Reviewed by:	bmilekic, jeff (somewhat)
Tested by:	rwatson, kris, gnn, scottl, mike at sentex dot net, others
2005-04-29 18:56:36 +00:00
bmilekic
f9dded75d0 Well, it seems that I pre-maturely removed the "All rights reserved"
statement from some files, so re-add it for the moment, until the
related legalese is sorted out.  This change affects:

sys/kern/kern_mbuf.c
sys/vm/memguard.c
sys/vm/memguard.h
sys/vm/uma.h
sys/vm/uma_core.c
sys/vm/uma_dbg.c
sys/vm/uma_dbg.h
sys/vm/uma_int.h
2005-02-16 21:45:59 +00:00
imp
f0bf889d0d /* -> /*- for license, minor formatting changes 2005-01-07 02:29:27 +00:00
bmilekic
764e80eed7 Add my copyright and update Jeff's copyright on UMA source files,
as per his request.

Discussed with: Jeffrey Roberson
2004-12-26 00:35:12 +00:00
cognet
f788045cc2 Remove useless casts. 2004-11-26 15:04:26 +00:00
bmilekic
c998cc2027 Rework the way slab header storage space is calculated in UMA.
- zone_large_init() stays pretty much the same.
- zone_small_init() will try to stash the slab header in the slab page
  being allocated if the amount of calculated wasted space is less
  than UMA_MAX_WASTE (for both the UMA_ZONE_REFCNT case and regular
  case).  If the amount of wasted space is >= UMA_MAX_WASTE, then
  UMA_ZONE_OFFPAGE will be set and the slab header will be allocated
  separately for better use of space.
- uma_startup() calculates the maximum ipers required in offpage slabs
  (so that the offpage slab header zone(s) can be sized accordingly).
  The algorithm used to calculate this replaces the old calculation
  (which only happened to work coincidentally).  We now iterate over
  possible object sizes, starting from the smallest one, until we
  determine that wastedspace calculated in zone_small_init() might
  end up being greater than UMA_MAX_WASTE, at which point we use the
  found object size to compute the maximum possible ipers.  The
  reason this works is because:
      - wastedspace versus objectsize is a see-saw function with
        local minima all equal to zero and local maxima growing
        directly proportioned to objectsize.  This implies that
        for objects up to or equal a certain objectsize, the see-saw
        remains entirely below UMA_MAX_WASTE, so for those objectsizes
        it is impossible to ever go OFFPAGE for slab headers.
      - ipers (items-per-slab) versus objectsize is an inversely
        proportional function which falls off very quickly (very large
        for small objectsizes).
      - To determine the maximum ipers we'll ever need from OFFPAGE
        slab headers we first find the largest objectsize for which
        we are guaranteed to not go offpage for and use it to compute
        ipers (as though we were offpage).  Since the only objectsizes
        allowed to go offpage are bigger than the found objectsize,
        and since ipers vs objectsize is inversely proportional (and
        monotonically decreasing), then we are guaranteed that the
        ipers computed is always >= what we will ever need in offpage
        slab headers.
- Define UMA_FRITM_SZ and UMA_FRITMREF_SZ to be the actual (possibly
  padded) size of each freelist index so that offset calculations are
  fixed.

This might fix weird data corruption problems and certainly allows
ARM to now boot to at least single-user (via simulator).

Tested on i386 UP by me.
Tested on sparc64 SMP by fenner.
Tested on ARM simulator to single-user by cognet.
2004-07-29 15:25:40 +00:00
bmilekic
f7574a2276 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
alc
8c7902507f Increase UMA_BOOT_PAGES because of changes to pv entry initialization in
revision 1.457 of i386/i386/pmap.c.
2004-01-18 05:51:06 +00:00
alc
eae1da31ea - Significantly reduce the number of preallocated pv entries in
pmap_init().  Such a large preallocation is unnecessary and wastes
   nearly eight megabytes of kernel virtual address space per gigabyte
   of managed physical memory.
 - Increase UMA_BOOT_PAGES by two.  This enables the removal of
   pmap_pv_allocf().  (Note: this function was only used during
   initialization, specifically, after pmap_init() but before
   pmap_init2().  During pmap_init2(), a new allocator is installed.)
2003-12-22 01:01:32 +00:00
jeff
accdfbd626 - Remove the working-set algorithm. Instead, use the per cpu buckets as the
working set cache.  This has several advantages.  Firstly, we never touch
   the per cpu queues now in the timeout handler.  This removes one more
   reason for having per cpu locks.  Secondly, it reduces the size of the zone
   by 8 bytes, bringing it under 200 bytes for a single proc x86 box.  This
   tidies up other logic as well.
 - The 'destroy' flag no longer needs to be passed to zone_drain() since it
   always frees everything in the zone's slabs.
 - cache_drain() is now only called from zone_dtor() and so it destroys by
   default.  It also does not need the destroy parameter now.
2003-09-19 23:27:46 +00:00
jeff
a234ab2fa7 - Remove the cache colorization code. We can't use it due to all of the
broken consumers of the malloc interface who assume that the allocated
   address will be an even multiple of the size.
 - Remove disabled time delay code on uma_reclaim().  The comment there said
   it all.  It was not an effective strategy and it should not be left in
   #if 0'd for all eternity.
2003-09-19 23:04:44 +00:00
jeff
30f275bb51 - Fix the silly flag situation in UMA. Remove redundant ZFLAG/ZONE flags
by accepting the user supplied flags directly.  Previously this was not
   done so that flags for the same field would not be defined in two
   different files.  Add comments in each header instructing future
   developers on how now to shoot their feet.
 - Fix a test for !OFFPAGE which should have been a test for HASH.  This would
   have caused a panic if we had ever destructed a malloc zone.  This also
   opens up the possibility that other zones could use the vsetobj() method
   rather than a hash.
2003-09-19 08:37:44 +00:00
jeff
b8696d32c3 - Initialize a pool of bucket zones so that we waste less space on zones that
don't cache as many items.
 - Introduce the bucket_alloc(), bucket_free() functions to wrap bucket
   allocation.  These functions select the appropriate bucket zone to
   allocate from or free to.
 - Rename ub_ptr to ub_cnt to reflect a change in its use.  ub_cnt now reflects
   the count of free items in the bucket.  This gets rid of many unnatural
   subtractions by 1 throughout the code.
 - Add ub_entries which reflects the number of entries possibly held in a
   bucket.
2003-09-19 06:26:45 +00:00
bmilekic
77b7809eb0 - When deciding whether to init the zone with small_init or large_init,
compare the zone element size (+1 for the byte of linkage) against
  UMA_SLAB_SIZE - sizeof(struct uma_slab), and not just UMA_SLAB_SIZE.
  Add a KASSERT in zone_small_init to make sure that the computed
  ipers (items per slab) for the zone is not zero, despite the addition
  of the check, just to be sure (this part submitted by: silby)

- UMA_ZONE_VM used to imply BUCKETCACHE.  Now it implies
  CACHEONLY instead.  CACHEONLY is like BUCKETCACHE in the
  case of bucket allocations, but in addition to that also ensures that
  we don't setup the zone with OFFPAGE slab headers allocated from the
  slabzone.  This means that we're not allowed to have a UMA_ZONE_VM
  zone initialized for large items (zone_large_init) because it would
  require the slab headers to be allocated from slabzone, and hence
  kmem_map.  Some of the zones init'd with UMA_ZONE_VM are so init'd
  before kmem_map is suballoc'd from kernel_map, which is why this
  change is necessary.
2003-08-11 19:39:45 +00:00
jeff
8512070a52 - Get rid of the ill-conceived uz_cachefree member of uma_zone.
- In sysctl_vm_zone use the per cpu locks to read the current cache
   statistics this makes them more accurate while under heavy load.

Submitted by:	tegge
2003-07-30 05:59:17 +00:00
bmilekic
bf27dce79b Move the pcpu lock out of the uma_cache and instead have a single set
of pcpu locks.  This makes uma_zone somewhat smaller (by (LOCKNAME_LEN *
sizeof(char) + sizeof(struct mtx) * maxcpu) bytes, to be exact).

No Objections from jeff.
2003-06-25 20:49:48 +00:00
phk
22c73f78e7 Prepend _ to internal union members to avoid ambiguity.
Found by:       FlexeLint
2003-05-31 19:52:15 +00:00
jeff
b7d774ad97 - Add support for machine dependant page allocation routines. MD code
may define UMA_MD_SMALL_ALLOC to make use of this feature.

Reviewed by:	peter, jake
2002-11-01 01:01:27 +00:00
jeff
f3621a00cf - Use my freebsd email alias in the copyright.
- Remove redundant instances of my email alias in the file summary.
2002-09-19 06:05:32 +00:00
jeff
aeb98331c1 - 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
julian
aa2dc0a5d9 Part 1 of KSE-III
The ability to schedule multiple threads per process
(one one cpu) by making ALL system calls optionally asynchronous.
to come: ia64 and power-pc patches, patches for gdb, test program (in tools)

Reviewed by:	Almost everyone who counts
	(at various times, peter, jhb, matt, alfred, mini, bernd,
	and a cast of thousands)

	NOTE: this is still Beta code, and contains lots of debugging stuff.
	expect slight instability in signals..
2002-06-29 17:26:22 +00:00
jeff
030d3fdb72 - Introduce the new M_NOVM option which tells uma to only check the currently
allocated slabs and bucket caches for free items.  It will not go ask the vm
  for pages.  This differs from M_NOWAIT in that it not only doesn't block, it
  doesn't even ask.

- Add a new zcreate option ZONE_VM, that sets the BUCKETCACHE zflag.  This
  tells uma that it should only allocate buckets out of the bucket cache, and
  not from the VM.  It does this by using the M_NOVM option to zalloc when
  getting a new bucket.  This is so that the VM doesn't recursively enter
  itself while trying to allocate buckets for vm_map_entry zones.  If there
  are already allocated buckets when we get here we'll still use them but
  otherwise we'll skip it.

- Use the ZONE_VM flag on vm map entries and pv entries on x86.
2002-06-17 22:02:41 +00:00
jeff
c52db1bfdf Add a new zone flag UMA_ZONE_MTXCLASS. This puts the zone in it's own
mutex class.  Currently this is only used for kmapentzone because kmapents
are are potentially allocated when freeing memory.  This is not dangerous
though because no other allocations will be done while holding the
kmapentzone lock.
2002-04-29 23:45:41 +00:00
jeff
5b62962da4 Fix the calculation that determines uz_maxpages. It was off for large zones.
Fortunately we have no large zones with maximums specified yet, so it wasn't
breaking anything.

Implement blocking when a zone exceeds the maximum and M_WAITOK is specified.
Previously this just failed like the old zone allocator did.  The old zone
allocator didn't support WAITOK/NOWAIT though so we should do what we
advertise.

While I was in there I cleaned up some more zalloc logic to further simplify
that code path and reduce redundant code.  This was needed to make the blocking
work properly anyway.
2002-04-14 01:56:25 +00:00
jeff
2d373c5269 Quiet witness warnings about acquiring several zone locks. In the case that
this happens it is OK.
2002-04-08 21:08:17 +00:00
jeff
7ab1f0e075 Rework most of the bucket allocation and free code so that per cpu locks are
never held across blocking operations.  Also, fix two other lock order
reversals that were exposed by jhb's witness change.

The free path previously had a bug that would cause it to skip the free bucket
list in some cases and go straight to allocating a new bucket.  This has been
fixed as well.

These changes made the bucket handling code much cleaner and removed quite a
few lock operations.  This should be marginally faster now.

It is now possible to call malloc w/o Giant and avoid any witness warnings.
This still isn't entirely safe though because malloc_type statistics are not
protected by any lock.
2002-04-08 02:42:55 +00:00
jeff
36e25e005a Spelling correction; s/seperate/separate/g
Submitted by:	eric
2002-04-07 22:56:48 +00:00
jhb
db9aa81e23 Change callers of mtx_init() to pass in an appropriate lock type name. In
most cases NULL is passed, but in some cases such as network driver locks
(which use the MTX_NETWORK_LOCK macro) and UMA zone locks, a name is used.

Tested on:	i386, alpha, sparc64
2002-04-04 21:03:38 +00:00
jeff
dff418f166 Add a new mtx_init option "MTX_DUPOK" which allows duplicate acquires of locks
with this flag.  Remove the dup_list and dup_ok code from subr_witness.  Now
we just check for the flag instead of doing string compares.

Also, switch the process lock, process group lock, and uma per cpu locks over
to this interface.  The original mechanism did not work well for uma because
per cpu lock names are unique to each zone.

Approved by:	jhb
2002-03-27 09:23:41 +00:00
jeff
2923687da3 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