slab: initialize unused alien cache entry as NULL at alloc_alien_cache().

Comparing with existing code, it's a simpler way to use kzalloc_node()
to ensure that each unused alien cache entry is NULL.

CC: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

diff --git a/mm/slab.c b/mm/slab.c
index 7d41f15..0c632a9 100644 (file)
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -983,13 +983,11 @@ static struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
 
        if (limit > 1)
                limit = 12;
-       ac_ptr = kmalloc_node(memsize, gfp, node);
+       ac_ptr = kzalloc_node(memsize, gfp, node);
        if (ac_ptr) {
                for_each_node(i) {
-                       if (i == node || !node_online(i)) {
-                               ac_ptr[i] = NULL;
+                       if (i == node || !node_online(i))
                                continue;
-                       }
                        ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d, gfp);
                        if (!ac_ptr[i]) {
                                for (i--; i >= 0; i--)