From 1807a1aaf5f2a35ea6d4b527b28bc8889d255a2f Mon Sep 17 00:00:00 2001
From: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Date: Wed, 22 Aug 2007 14:01:49 -0700
Subject: 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 <suresh.b.siddha@intel.com>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/slab.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
(limited to 'mm')
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)) {
--
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