linux.git/mm/slab_common.c, branch v3.12

slab_common: Do not check for duplicate slab names

2013-09-28T06:47:41+00:00

SLUB can alias multiple slab kmem_create_requests to one slab cache to save
memory and increase the cache hotness. As a result the name of the slab can be
stale. Only check the name for duplicates if we are in debug mode where we do
not merge multiple caches.

This fixes the following problem reported by Jonathan Brassow:

  The problem with kmem_cache* is this:

  *) Assume CONFIG_SLUB is set
  1) kmem_cache_create(name="foo-a")
  - creates new kmem_cache structure
  2) kmem_cache_create(name="foo-b")
  - If identical cache characteristics, it will be merged with the previously
    created cache associated with "foo-a".  The cache's refcount will be
    incremented and an alias will be created via sysfs_slab_alias().
  3) kmem_cache_destroy()
  - Attempting to destroy cache associated with "foo-a", but instead the
    refcount is simply decremented.  I don't even think the sysfs aliases are
    ever removed...
  4) kmem_cache_create(name="foo-a")
  - This FAILS because kmem_cache_sanity_check colides with the existing
    name ("foo-a") associated with the non-removed cache.

  This is a problem for RAID (specifically dm-raid) because the name used
  for the kmem_cache_create is ("raid%d-%p", level, mddev).  If the cache
  persists for long enough, the memory address of an old mddev will be
  reused for a new mddev - causing an identical formulation of the cache
  name.  Even though kmem_cache_destory had long ago been used to delete
  the old cache, the merging of caches has cause the name and cache of that
  old instance to be preserved and causes a colision (and thus failure) in
  kmem_cache_create().  I see this regularly in my testing.

Reported-by: Jonathan Brassow 
Signed-off-by: Christoph Lameter 
Signed-off-by: Pekka Enberg

mm/sl[aou]b: Move kmallocXXX functions to common code

2013-09-04T17:51:33+00:00

The kmalloc* functions of all slab allcoators are similar now so
lets move them into slab.h. This requires some function naming changes
in slob.

As a results of this patch there is a common set of functions for
all allocators. Also means that kmalloc_large() is now available
in general to perform large order allocations that go directly
via the page allocator. kmalloc_large() can be substituted if
kmalloc() throws warnings because of too large allocations.

kmalloc_large() has exactly the same semantics as kmalloc but
can only used for allocations > PAGE_SIZE.

Signed-off-by: Christoph Lameter 
Signed-off-by: Pekka Enberg

mm, slab_common: add 'unlikely' to size check of kmalloc_slab()

2013-08-14T15:26:10+00:00

Size is usually below than KMALLOC_MAX_SIZE.
If we add a 'unlikely' macro, compiler can make better code.

Acked-by: Christoph Lameter 
Signed-off-by: Joonsoo Kim 
Signed-off-by: Pekka Enberg

Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux

2013-07-14T22:14:29+00:00

Pull slab update from Pekka Enberg:
 "Highlights:

  - Fix for boot-time problems on some architectures due to
    init_lock_keys() not respecting kmalloc_caches boundaries
    (Christoph Lameter)

  - CONFIG_SLUB_CPU_PARTIAL requested by RT folks (Joonsoo Kim)

  - Fix for excessive slab freelist draining (Wanpeng Li)

  - SLUB and SLOB cleanups and fixes (various people)"

I ended up editing the branch, and this avoids two commits at the end
that were immediately reverted, and I instead just applied the oneliner
fix in between myself.

* 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
  slub: Check for page NULL before doing the node_match check
  mm/slab: Give s_next and s_stop slab-specific names
  slob: Check for NULL pointer before calling ctor()
  slub: Make cpu partial slab support configurable
  slab: add kmalloc() to kernel API documentation
  slab: fix init_lock_keys
  slob: use DIV_ROUND_UP where possible
  slub: do not put a slab to cpu partial list when cpu_partial is 0
  mm/slub: Use node_nr_slabs and node_nr_objs in get_slabinfo
  mm/slub: Drop unnecessary nr_partials
  mm/slab: Fix /proc/slabinfo unwriteable for slab
  mm/slab: Sharing s_next and s_stop between slab and slub
  mm/slab: Fix drain freelist excessively
  slob: Rework #ifdeffery in slab.h
  mm, slab: moved kmem_cache_alloc_node comment to correct place

mm/slab: Give s_next and s_stop slab-specific names

2013-07-08T08:02:17+00:00

Give s_next and s_stop slab-specific names instead of exporting
"s_next" and "s_stop".

Signed-off-by: Wanpeng Li 
Signed-off-by: Pekka Enberg

mm/slab: Fix /proc/slabinfo unwriteable for slab

2013-07-07T15:37:47+00:00

Slab have some tunables like limit, batchcount, and sharedfactor can be
tuned through function slabinfo_write. Commit (b7454ad3: mm/sl[au]b: Move
slabinfo processing to slab_common.c) uncorrectly change /proc/slabinfo
unwriteable for slab, this patch fix it by revert to original mode.

Acked-by: Christoph Lameter 
Signed-off-by: Wanpeng Li 
Signed-off-by: Pekka Enberg

mm/slab: Sharing s_next and s_stop between slab and slub

2013-07-07T15:37:47+00:00

This patch shares s_next and s_stop between slab and slub.

Acked-by: Christoph Lameter 
Signed-off-by: Wanpeng Li 
Signed-off-by: Pekka Enberg

slab: prevent warnings when allocating with __GFP_NOWARN

2013-06-13T07:01:58+00:00

Sasha Levin noticed that the warning introduced by commit 6286ae9
("slab: Return NULL for oversized allocations) is being triggered:

  WARNING: CPU: 15 PID: 21519 at mm/slab_common.c:376 kmalloc_slab+0x2f/0xb0()
  can: request_module (can-proto-4) failed.
  mpoa: proc_mpc_write: could not parse ''
  Modules linked in:
  CPU: 15 PID: 21519 Comm: trinity-child15 Tainted: G W    3.10.0-rc4-next-20130607-sasha-00011-gcd78395-dirty #2
   0000000000000009 ffff880020a95e30 ffffffff83ff4041 0000000000000000
   ffff880020a95e68 ffffffff8111fe12 fffffffffffffff0 00000000000082d0
   0000000000080000 0000000000080000 0000000001400000 ffff880020a95e78
  Call Trace:
   [] dump_stack+0x4e/0x82
   [] warn_slowpath_common+0x82/0xb0
   [] warn_slowpath_null+0x15/0x20
   [] kmalloc_slab+0x2f/0xb0
   [] __kmalloc+0x24/0x4b0
   [] ? security_capable+0x13/0x20
   [] ? pipe_fcntl+0x107/0x210
   [] pipe_fcntl+0x107/0x210
   [] ? fget_raw_light+0x130/0x3f0
   [] SyS_fcntl+0x60b/0x6a0
   [] tracesys+0xe1/0xe6

Andrew Morton writes:

  __GFP_NOWARN is frequently used by kernel code to probe for "how big
  an allocation can I get".  That's a bit lame, but it's used on slow
  paths and is pretty simple.

However, SLAB would still spew a warning when a big allocation happens
if the __GFP_NOWARN flag is _not_ set to expose kernel bugs.

Signed-off-by: Sasha Levin 
[ penberg@kernel.org: improve changelog ]
Signed-off-by: Pekka Enberg

mm/slab: Fix crash during slab init

2013-05-08T22:02:33+00:00

Commit 8a965b3baa89 ("mm, slab_common: Fix bootstrap creation of kmalloc
caches") introduced a regression that caused us to crash early during
boot.  The commit was introducing ordering of slab creation, making sure
two odd-sized slabs were created after specific powers of two sizes.

But, if any of the power of two slabs were created earlier during boot,
slabs at index 1 or 2 might not get created at all.  This patch makes
sure none of the slabs get skipped.

Tony Lindgren bisected this down to the offending commit, which really
helped because bisect kept bringing me to almost but not quite this one.

Signed-off-by: Chris Mason 
Acked-by: Christoph Lameter 
Acked-by: Tony Lindgren 
Acked-by: Soren Brinkmann 
Tested-by: Tetsuo Handa 
Tested-by: Konrad Rzeszutek Wilk 
Signed-off-by: Linus Torvalds

mm, slab_common: Fix bootstrap creation of kmalloc caches

2013-05-06T20:22:17+00:00

For SLAB the kmalloc caches must be created in ascending sizes in order
for the OFF_SLAB sub-slab cache to work properly.

Create the non power of two caches immediately after the prior power of
two kmalloc cache. Do not create the non power of two caches before all
other caches.

Reported-and-tested-by: Tetsuo Handa 
Signed-off-by: Christoph Lamete 
Link: http://lkml.kernel.org/r/201305040348.CIF81716.OStQOHFJMFLOVF@I-love.SAKURA.ne.jp
Signed-off-by: Pekka Enberg