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| author | Christoph Lameter <cl@linux.com> | 2014-04-07 15:39:42 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-07 16:36:14 -0700 |
| commit | 88da03a67674bcd6e9ecf18a0a182cf1303056ba (patch) | |
| tree | f822c90ff7a8e62e6d7c3c82854b510786e7222b /mm | |
| parent | 3ed66e910c91eb914b5c1f2d434538fe68bb8a56 (diff) | |
| download | linux-0-day-88da03a67674bcd6e9ecf18a0a182cf1303056ba.tar.gz linux-0-day-88da03a67674bcd6e9ecf18a0a182cf1303056ba.tar.xz | |
slub: use raw_cpu_inc for incrementing statistics
Statistics are not critical to the operation of the allocation but
should also not cause too much overhead.
When __this_cpu_inc is altered to check if preemption is disabled this
triggers. Use raw_cpu_inc to avoid the checks. Using this_cpu_ops may
cause interrupt disable/enable sequences on various arches which may
significantly impact allocator performance.
[akpm@linux-foundation.org: add comment]
Signed-off-by: Christoph Lameter <cl@linux.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/slub.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/mm/slub.c b/mm/slub.c index e7451861f95d5..f620bbf4054aa 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -224,7 +224,11 @@ static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { } static inline void stat(const struct kmem_cache *s, enum stat_item si) { #ifdef CONFIG_SLUB_STATS - __this_cpu_inc(s->cpu_slab->stat[si]); + /* + * The rmw is racy on a preemptible kernel but this is acceptable, so + * avoid this_cpu_add()'s irq-disable overhead. + */ + raw_cpu_inc(s->cpu_slab->stat[si]); #endif } |