From 1807a1aaf5f2a35ea6d4b527b28bc8889d255a2f Mon Sep 17 00:00:00 2001 From: "Siddha, Suresh B" Date: Wed, 22 Aug 2007 14:01:49 -0700 Subject: [PATCH] slab: skip calling cache_free_alien() when the platform is not numa capable Skip calling cache_free_alien() when the platform is not numa capable. This will avoid cache misses that happen while accessing slabp (which is per page memory reference) to get nodeid. Instead use a global variable to skip the call, which is mostly likely to be present in the cache. This gives a 0.8% performance boost with the database oltp workload on a quad-core SMP platform and by any means the number is not small :) Signed-off-by: Suresh Siddha Acked-by: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slab.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index a684778b2b41..6f6abef83a1a 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -883,6 +883,7 @@ static void __slab_error(const char *function, struct kmem_cache *cachep, */ static int use_alien_caches __read_mostly = 1; +static int numa_platform __read_mostly = 1; static int __init noaliencache_setup(char *s) { use_alien_caches = 0; @@ -1399,8 +1400,10 @@ void __init kmem_cache_init(void) int order; int node; - if (num_possible_nodes() == 1) + if (num_possible_nodes() == 1) { use_alien_caches = 0; + numa_platform = 0; + } for (i = 0; i < NUM_INIT_LISTS; i++) { kmem_list3_init(&initkmem_list3[i]); @@ -3558,7 +3561,14 @@ static inline void __cache_free(struct kmem_cache *cachep, void *objp) check_irq_off(); objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0)); - if (cache_free_alien(cachep, objp)) + /* + * Skip calling cache_free_alien() when the platform is not numa. + * This will avoid cache misses that happen while accessing slabp (which + * is per page memory reference) to get nodeid. Instead use a global + * variable to skip the call, which is mostly likely to be present in + * the cache. + */ + if (numa_platform && cache_free_alien(cachep, objp)) return; if (likely(ac->avail < ac->limit)) {