From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f171.google.com (mail-wi0-f171.google.com [209.85.212.171]) by kanga.kvack.org (Postfix) with ESMTP id 3C73C82F5F for ; Wed, 12 Aug 2015 06:45:43 -0400 (EDT) Received: by wicja10 with SMTP id ja10so22022881wic.1 for ; Wed, 12 Aug 2015 03:45:42 -0700 (PDT) Received: from outbound-smtp04.blacknight.com (outbound-smtp04.blacknight.com. [81.17.249.35]) by mx.google.com with ESMTPS id dx9si9821249wib.80.2015.08.12.03.45.37 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Wed, 12 Aug 2015 03:45:37 -0700 (PDT) Received: from mail.blacknight.com (pemlinmail05.blacknight.ie [81.17.254.26]) by outbound-smtp04.blacknight.com (Postfix) with ESMTPS id D5CD599008 for ; Wed, 12 Aug 2015 10:45:36 +0000 (UTC) From: Mel Gorman Subject: [PATCH 04/10] mm, page_alloc: Remove unnecessary taking of a seqlock when cpusets are disabled Date: Wed, 12 Aug 2015 11:45:29 +0100 Message-Id: <1439376335-17895-5-git-send-email-mgorman@techsingularity.net> In-Reply-To: <1439376335-17895-1-git-send-email-mgorman@techsingularity.net> References: <1439376335-17895-1-git-send-email-mgorman@techsingularity.net> Sender: owner-linux-mm@kvack.org List-ID: To: Linux-MM Cc: Johannes Weiner , Rik van Riel , Vlastimil Babka , David Rientjes , Joonsoo Kim , Michal Hocko , LKML , Mel Gorman There is a seqcounter that protects against spurious allocation failures when a task is changing the allowed nodes in a cpuset. There is no need to check the seqcounter until a cpuset exists. Signed-off-by: Mel Gorman Acked-by: David Rientjes Acked-by: Vlastimil Babka --- include/linux/cpuset.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h index 1b357997cac5..6eb27cb480b7 100644 --- a/include/linux/cpuset.h +++ b/include/linux/cpuset.h @@ -104,6 +104,9 @@ extern void cpuset_print_task_mems_allowed(struct task_struct *p); */ static inline unsigned int read_mems_allowed_begin(void) { + if (!cpusets_enabled()) + return 0; + return read_seqcount_begin(¤t->mems_allowed_seq); } @@ -115,6 +118,9 @@ static inline unsigned int read_mems_allowed_begin(void) */ static inline bool read_mems_allowed_retry(unsigned int seq) { + if (!cpusets_enabled()) + return false; + return read_seqcount_retry(¤t->mems_allowed_seq, seq); } -- 2.4.6 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org