[PATCH] mm: optimize numa policy handling in slab allocator

Move the interrupt check from slab_node into ___cache_alloc and adds an
"unlikely()" to avoid pipeline stalls on some architectures.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 1 insertions, 4 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 71430d44082..73790188b0e 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -982,9 +982,6 @@ static unsigned interleave_nodes(struct mempolicy *policy)
  */
 unsigned slab_node(struct mempolicy *policy)
 {
-        if (in_interrupt())
-                return numa_node_id();
-
         switch (policy->policy) {
         case MPOL_INTERLEAVE:
                 return interleave_nodes(policy);
diff --git a/mm/slab.c b/mm/slab.c
index 9025608696e..6f8495e2185 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2574,7 +2574,7 @@ static inline void *____cache_alloc(kmem_cache_t *cachep, gfp_t flags)
         struct array_cache *ac;
 
 #ifdef CONFIG_NUMA
-        if (current->mempolicy) {
+        if (unlikely(current->mempolicy && !in_interrupt())) {
                 int nid = slab_node(current->mempolicy);
 
                 if (nid != numa_node_id())