[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>

diff --git a/mm/slab.c b/mm/slab.c
index 4cbac24..168bfe9 100644 (file)
--- 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)) {