From: Joe Perches <joe@perches.com>
Date: Wed, 11 Sep 2013 00:02:51 +0000 (-0700)
Subject: slab: Make allocations with GFP_ZERO slightly more efficient
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=5087c8229986cc502c807a15f8ea416b0ef22346;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

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>
---

diff --git a/mm/slab.c b/mm/slab.c
index 54eba8a65370..8347d803a23f 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -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;
 }