linux-kernel - [PATCH v3 1/9] slab: add unlikely macro to help compiler

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue,  1 Jul 2014 17:27:30 +0900
From:	Joonsoo Kim <iamjoonsoo.kim@....com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Christoph Lameter <cl@...ux.com>,
	Pekka Enberg <penberg@...nel.org>,
	David Rientjes <rientjes@...gle.com>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	Vladimir Davydov <vdavydov@...allels.com>,
	Joonsoo Kim <iamjoonsoo.kim@....com>
Subject: [PATCH v3 1/9] slab: add unlikely macro to help compiler

slab_should_failslab() is called on every allocation, so to optimize it
is reasonable. We normally don't allocate from kmem_cache. It is just
used when new kmem_cache is created, so it's very rare case. Therefore,
add unlikely macro to help compiler optimization.

Acked-by: David Rientjes <rientjes@...gle.com>
Acked-by: Christoph Lameter <cl@...ux.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@....com>
---
 mm/slab.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/slab.c b/mm/slab.c
index 179272f..f8a0ed1 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3067,7 +3067,7 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
 
 static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags)
 {
-	if (cachep == kmem_cache)
+	if (unlikely(cachep == kmem_cache))
 		return false;
 
 	return should_failslab(cachep->object_size, flags, cachep->flags);
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/