Anyways the statistics in slub should be low impact and able to
be placed anywhere. So I think we need this patch to avoid
the preemption checks begin triggered.
Subject: 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.
__this_cpu_inc now checks if preemption is disabled and 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.
Signed-off-by: Christoph Lameter <c...@linux.com>
Index: linux/mm/slub.c
===================================================================
--- linux.orig/mm/slub.c 2014-03-07 14:10:30.142777022 -0600
+++ linux/mm/slub.c 2014-03-18 09:39:15.675035324 -0500
@@ -224,7 +224,7 @@
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]);
+ raw_cpu_inc(s->cpu_slab->stat[si]);
#endif
}
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