[PATCH] x86-64: skip cache_free_alien() on non NUMA

Set use_alien_caches to 0 on non NUMA platforms.  And avoid calling the
cache_free_alien() when use_alien_caches is not set.  This will avoid the
cache miss that happens while dereferencing slabp to get nodeid.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/mm/slab.c b/mm/slab.c
index 4cbac24ae2f1..168bfe9d8ffe 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1146,7 +1146,7 @@ static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
          * Make sure we are not freeing a object from another node to the array
          * cache on this cpu.
          */
-        if (likely(slabp->nodeid == node) || unlikely(!use_alien_caches))
+        if (likely(slabp->nodeid == node))
                 return 0;
 
         l3 = cachep->nodelists[node];
@@ -1394,6 +1394,9 @@ void __init kmem_cache_init(void)
         int order;
         int node;
 
+        if (num_possible_nodes() == 1)
+                use_alien_caches = 0;
+
         for (i = 0; i < NUM_INIT_LISTS; i++) {
                 kmem_list3_init(&initkmem_list3[i]);
                 if (i < MAX_NUMNODES)
@@ -3563,7 +3566,7 @@ 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))
+        if (use_alien_caches && cache_free_alien(cachep, objp))
                 return;
 
         if (likely(ac->avail < ac->limit)) {