From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f182.google.com (mail-wi0-f182.google.com [209.85.212.182]) by kanga.kvack.org (Postfix) with ESMTP id 95DAF6B0256 for ; Mon, 24 Aug 2015 08:09:59 -0400 (EDT) Received: by wicne3 with SMTP id ne3so70185314wic.0 for ; Mon, 24 Aug 2015 05:09:59 -0700 (PDT) Received: from outbound-smtp01.blacknight.com (outbound-smtp01.blacknight.com. [81.17.249.7]) by mx.google.com with ESMTPS id wu1si31711125wjc.31.2015.08.24.05.09.52 for (version=TLS1 cipher=RC4-SHA bits=128/128); Mon, 24 Aug 2015 05:09:53 -0700 (PDT) Received: from mail.blacknight.com (pemlinmail02.blacknight.ie [81.17.254.11]) by outbound-smtp01.blacknight.com (Postfix) with ESMTPS id C251999104 for ; Mon, 24 Aug 2015 12:09:52 +0000 (UTC) From: Mel Gorman Subject: [PATCH 03/12] mm, page_alloc: Remove unnecessary taking of a seqlock when cpusets are disabled Date: Mon, 24 Aug 2015 13:09:42 +0100 Message-Id: <1440418191-10894-4-git-send-email-mgorman@techsingularity.net> In-Reply-To: <1440418191-10894-1-git-send-email-mgorman@techsingularity.net> References: <1440418191-10894-1-git-send-email-mgorman@techsingularity.net> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Johannes Weiner , Rik van Riel , Vlastimil Babka , David Rientjes , Joonsoo Kim , Michal Hocko , Linux-MM , 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: Christoph Lameter 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