slab: introduce alien_cache

Currently, we use array_cache for alien_cache.  Although they are mostly
similar, there is one difference, that is, need for spinlock.  We don't
need spinlock for array_cache itself, but to use array_cache for
alien_cache, array_cache structure should have spinlock.  This is
needless overhead, so removing it would be better.  This patch prepare
it by introducing alien_cache and using it.  In the following patch, we
remove spinlock in array_cache.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/mm/slab.h b/mm/slab.h
index 3822b65..928823e 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -276,7 +276,7 @@ struct kmem_cache_node {
 	unsigned int free_limit;
 	unsigned int colour_next;	/* Per-node cache coloring */
 	struct array_cache *shared;	/* shared per node */
-	struct array_cache **alien;	/* on other nodes */
+	struct alien_cache **alien;	/* on other nodes */
 	unsigned long next_reap;	/* updated without locking */
 	int free_touched;		/* updated without locking */
 #endif