From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753293Ab3IKACz (ORCPT ); Tue, 10 Sep 2013 20:02:55 -0400 Received: from smtprelay0111.hostedemail.com ([216.40.44.111]:41106 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751890Ab3IKACx (ORCPT ); Tue, 10 Sep 2013 20:02:53 -0400 X-Session-Marker: 6A6F6540706572636865732E636F6D X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,joe@perches.com,:::::::::,RULES_HIT:41:355:379:541:800:960:973:988:989:1260:1261:1277:1311:1313:1314:1345:1373:1437:1515:1516:1518:1534:1541:1593:1594:1711:1730:1747:1777:1792:2393:2559:2562:2828:3138:3139:3140:3141:3142:3352:3865:3867:4321:5007:7652:8784:9592:10004:10400:10848:11658:11914:12438:12517:12519:12555:13069:13311:13357,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0 X-HE-Tag: party67_704cf563ecb4b X-Filterd-Recvd-Size: 2072 Message-ID: <1378857771.15187.4.camel@joe-AO722> Subject: [PATCH] slab: Make allocations with GFP_ZERO slightly more efficient From: Joe Perches To: Christoph Lameter , Pekka Enberg , Matt Mackall Cc: linux-mm , LKML Date: Tue, 10 Sep 2013 17:02:51 -0700 Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: Evolution 3.6.4-0ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use the likely mechanism already around valid pointer tests to better choose when to memset to 0 allocations with __GFP_ZERO Signed-off-by: Joe Perches --- mm/slab.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index 2580db0..94e7e54 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -3392,11 +3392,11 @@ 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; } @@ -3457,11 +3457,11 @@ 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; }