slab: Make allocations with GFP_ZERO slightly more efficient

Use the likely mechanism already around valid
pointer tests to better choose when to memset
to 0 allocations with __GFP_ZERO

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This commit is contained in:
Joe Perches 2013-09-10 17:02:51 -07:00 committed by Pekka Enberg
parent 8fc9cf420b
commit 5087c82299

View File

@ -3278,11 +3278,11 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
kmemleak_alloc_recursive(ptr, cachep->object_size, 1, cachep->flags,
flags);
if (likely(ptr))
if (likely(ptr)) {
kmemcheck_slab_alloc(cachep, flags, ptr, cachep->object_size);
if (unlikely((flags & __GFP_ZERO) && ptr))
memset(ptr, 0, cachep->object_size);
if (unlikely(flags & __GFP_ZERO))
memset(ptr, 0, cachep->object_size);
}
return ptr;
}
@ -3343,11 +3343,11 @@ slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller)
flags);
prefetchw(objp);
if (likely(objp))
if (likely(objp)) {
kmemcheck_slab_alloc(cachep, flags, objp, cachep->object_size);
if (unlikely((flags & __GFP_ZERO) && objp))
memset(objp, 0, cachep->object_size);
if (unlikely(flags & __GFP_ZERO))
memset(objp, 0, cachep->object_size);
}
return objp;
}