linux-stable.git/include/linux/slab.h, branch v4.5.3

mm: memcontrol: move kmem accounting code to CONFIG_MEMCG

2016-01-21T01:09:18+00:00

The cgroup2 memory controller will account important in-kernel memory
consumers per default.  Move all necessary components to CONFIG_MEMCG.

Signed-off-by: Johannes Weiner 
Acked-by: Vladimir Davydov 
Cc: Michal Hocko 
Cc: Arnd Bergmann 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

slab: add SLAB_ACCOUNT flag

2016-01-15T00:00:49+00:00

Currently, if we want to account all objects of a particular kmem cache,
we have to pass __GFP_ACCOUNT to each kmem_cache_alloc call, which is
inconvenient.  This patch introduces SLAB_ACCOUNT flag which if passed
to kmem_cache_create will force accounting for every allocation from
this cache even if __GFP_ACCOUNT is not passed.

This patch does not make any of the existing caches use this flag - it
will be done later in the series.

Note, a cache with SLAB_ACCOUNT cannot be merged with a cache w/o
SLAB_ACCOUNT, because merged caches share the same kmem_cache struct and
hence cannot have different sets of SLAB_* flags.  Thus using this flag
will probably reduce the number of merged slabs even if kmem accounting
is not used (only compiled in).

Signed-off-by: Vladimir Davydov 
Suggested-by: Tejun Heo 
Acked-by: Johannes Weiner 
Acked-by: Michal Hocko 
Cc: Greg Thelen 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

slab/slub: adjust kmem_cache_alloc_bulk API

2015-11-22T19:58:44+00:00

Adjust kmem_cache_alloc_bulk API before we have any real users.

Adjust API to return type 'int' instead of previously type 'bool'.  This
is done to allow future extension of the bulk alloc API.

A future extension could be to allow SLUB to stop at a page boundary, when
specified by a flag, and then return the number of objects.

The advantage of this approach, would make it easier to make bulk alloc
run without local IRQs disabled.  With an approach of cmpxchg "stealing"
the entire c->freelist or page->freelist.  To avoid overshooting we would
stop processing at a slab-page boundary.  Else we always end up returning
some objects at the cost of another cmpxchg.

To keep compatible with future users of this API linking against an older
kernel when using the new flag, we need to return the number of allocated
objects with this API change.

Signed-off-by: Jesper Dangaard Brouer 
Cc: Vladimir Davydov 
Acked-by: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

slab.h: sprinkle __assume_aligned attributes

2015-11-21T00:17:32+00:00

The various allocators return aligned memory.  Telling the compiler that
allows it to generate better code in many cases, for example when the
return value is immediately passed to memset().

Some code does become larger, but at least we win twice as much as we lose:

$ scripts/bloat-o-meter /tmp/vmlinux vmlinux
add/remove: 0/0 grow/shrink: 13/52 up/down: 995/-2140 (-1145)

An example of the different (and smaller) code can be seen in mm_alloc(). Before:

:       48 8d 78 08             lea    0x8(%rax),%rdi
:       48 89 c1                mov    %rax,%rcx
:       48 89 c2                mov    %rax,%rdx
:       48 c7 00 00 00 00 00    movq   $0x0,(%rax)
:       48 c7 80 48 03 00 00    movq   $0x0,0x348(%rax)
:       00 00 00 00
:       31 c0                   xor    %eax,%eax
:       48 83 e7 f8             and    $0xfffffffffffffff8,%rdi
:       48 29 f9                sub    %rdi,%rcx
:       81 c1 50 03 00 00       add    $0x350,%ecx
:       c1 e9 03                shr    $0x3,%ecx
:       f3 48 ab                rep stos %rax,%es:(%rdi)

After:

:       48 89 c2                mov    %rax,%rdx
:       b9 6a 00 00 00          mov    $0x6a,%ecx
:       31 c0                   xor    %eax,%eax
:       48 89 d7                mov    %rdx,%rdi
:       f3 48 ab                rep stos %rax,%es:(%rdi)

So gcc's strategy is to do two possibly (but not really, of course)
unaligned stores to the first and last word, then do an aligned rep stos
covering the middle part with a little overlap.  Maybe arches which do not
allow unaligned stores gain even more.

I don't know if gcc can actually make use of alignments greater than 8 for
anything, so one could probably drop the __assume_xyz_alignment macros and
just use __assume_aligned(8).

The increases in code size are mostly caused by gcc deciding to
opencode strlen() using the check-four-bytes-at-a-time trick when it
knows the buffer is sufficiently aligned (one function grew by 200
bytes). Now it turns out that many of these strlen() calls showing up
were in fact redundant, and they're gone from -next. Applying the two
patches to next-20151001 bloat-o-meter instead says

add/remove: 0/0 grow/shrink: 6/52 up/down: 244/-2140 (-1896)

Signed-off-by: Rasmus Villemoes 
Acked-by: Christoph Lameter 
Cc: David Rientjes 
Cc: Pekka Enberg 
Cc: Joonsoo Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

slab: convert slab_is_available() to boolean

2015-11-06T03:34:48+00:00

A good candidate to return a boolean result.

Signed-off-by: Denis Kirjanov 
Cc: Christoph Lameter 
Reviewed-by: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

slab: infrastructure for bulk object allocation and freeing

2015-09-04T23:54:41+00:00

Add the basic infrastructure for alloc/free operations on pointer arrays.
It includes a generic function in the common slab code that is used in
this infrastructure patch to create the unoptimized functionality for slab
bulk operations.

Allocators can then provide optimized allocation functions for situations
in which large numbers of objects are needed.  These optimization may
avoid taking locks repeatedly and bypass metadata creation if all objects
in slab pages can be used to provide the objects required.

Allocators can extend the skeletons provided and add their own code to the
bulk alloc and free functions.  They can keep the generic allocation and
freeing and just fall back to those if optimizations would not work (like
for example when debugging is on).

Signed-off-by: Christoph Lameter 
Signed-off-by: Jesper Dangaard Brouer 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Fix kmalloc slab creation sequence

2015-06-29T17:49:51+00:00

This patch restores the slab creation sequence that was broken by commit
4066c33d0308f8 and also reverts the portions that introduced the
KMALLOC_LOOP_XXX macros. Those can never really work since the slab creation
is much more complex than just going from a minimum to a maximum number.

The latest upstream kernel boots cleanly on my machine with a 64 bit x86
configuration under KVM using either SLAB or SLUB.

Fixes: 4066c33d0308f8 ("support the slub_debug boot option")
Reported-by: Theodore Ts'o 
Signed-off-by: Christoph Lameter 
Signed-off-by: Linus Torvalds

linux/slab.h: fix three off-by-one typos in comment

2015-06-25T00:49:41+00:00

The first is a keyboard-off-by-one, the other two the ordinary mathy kind.

Signed-off-by: Rasmus Villemoes 
Acked-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/slab_common: support the slub_debug boot option on specific object size

2015-06-25T00:49:40+00:00

The slub_debug=PU,kmalloc-xx cannot work because in the
create_kmalloc_caches() the s->name is created after the
create_kmalloc_cache() is called.  The name is NULL in the
create_kmalloc_cache() so the kmem_cache_flags() would not set the
slub_debug flags to the s->flags.  The fix here set up a kmalloc_names
string array for the initialization purpose and delete the dynamic name
creation of kmalloc_caches.

[akpm@linux-foundation.org: s/kmalloc_names/kmalloc_info/, tweak comment text]
Signed-off-by: Gavin Guo 
Acked-by: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, slab: correct config option in comment

2015-04-14T23:48:59+00:00

CONFIG_SLAB_DEBUG doesn't exist, CONFIG_DEBUG_SLAB does.

Signed-off-by: David Rientjes 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: Joonsoo Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds