From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f175.google.com (mail-wi0-f175.google.com [209.85.212.175]) by kanga.kvack.org (Postfix) with ESMTP id 120839003C7 for ; Mon, 20 Jul 2015 04:00:33 -0400 (EDT) Received: by wicgb10 with SMTP id gb10so19399911wic.1 for ; Mon, 20 Jul 2015 01:00:32 -0700 (PDT) Received: from outbound-smtp01.blacknight.com (outbound-smtp01.blacknight.com. [81.17.249.7]) by mx.google.com with ESMTPS id w2si11996802wiy.40.2015.07.20.01.00.22 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 20 Jul 2015 01:00:23 -0700 (PDT) Received: from mail.blacknight.com (pemlinmail03.blacknight.ie [81.17.254.16]) by outbound-smtp01.blacknight.com (Postfix) with ESMTPS id A4B1198BE1 for ; Mon, 20 Jul 2015 08:00:22 +0000 (UTC) From: Mel Gorman Subject: [PATCH 04/10] mm, page_alloc: Remove unnecessary taking of a seqlock when cpusets are disabled Date: Mon, 20 Jul 2015 09:00:13 +0100 Message-Id: <1437379219-9160-5-git-send-email-mgorman@suse.com> In-Reply-To: <1437379219-9160-1-git-send-email-mgorman@suse.com> References: <1437379219-9160-1-git-send-email-mgorman@suse.com> Sender: owner-linux-mm@kvack.org List-ID: To: Linux-MM Cc: Johannes Weiner , Rik van Riel , Vlastimil Babka , Pintu Kumar , Xishi Qiu , Gioh Kim , LKML , Mel Gorman From: Mel Gorman There is a seqcounter that protects spurious allocation fails 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 --- 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); } -- 2.4.3 -- 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