From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932659Ab1ISV1g (ORCPT ); Mon, 19 Sep 2011 17:27:36 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:64682 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932601Ab1ISV0p (ORCPT ); Mon, 19 Sep 2011 17:26:45 -0400 X-Authority-Analysis: v=1.1 cv=agqPq5NoKwAPC9P66H7dbYUCjxvmT73as08i4x3aqAA= c=1 sm=0 a=vhdKIqpQuCYA:10 a=aNpYe9hrFvkA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=17wjrS5wAhQaEczCPkpxpQ==:17 a=20KFwNOVAAAA:8 a=ufHFDILaAAAA:8 a=1XWaLZrsAAAA:8 a=omOdbC7AAAAA:8 a=VnNF1IyMAAAA:8 a=meVymXHHAAAA:8 a=NWvjgwRQGdOIabK6crAA:9 a=ZnwbrsSBWAVPcJVNnfYA:7 a=jEp0ucaQiEUA:10 a=l7ZknGph1ugA:10 a=UTB_XpHje0EA:10 a=jeBq3FmKZ4MA:10 a=17wjrS5wAhQaEczCPkpxpQ==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.83.30 Message-Id: <20110919212641.015320989@goodmis.org> User-Agent: quilt/0.48-1 Date: Mon, 19 Sep 2011 17:20:43 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Thomas Gleixner , Peter Zijlstra , Christoph Lameter , Johannes Weiner , Greg Thelen , KAMEZAWA Hiroyuki , Balbir Singh , Daisuke Nishimura Subject: [RFC][PATCH 3/5] memcg: Disable preemption in memcg_check_events() References: <20110919212040.745370781@goodmis.org> Content-Disposition: inline; filename=0003-memcg-Disable-preemption-in-memcg_check_events.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Rostedt The code in memcg_check_events() calls this_cpu_read() on different variables without disabling preemption, and can cause the calculations to be done from two different CPU variables. Disable preemption throughout the check to keep apples and oranges from becoming a mixed drink. Signed-off-by: Johannes Weiner Signed-off-by: Greg Thelen Acked-by: KAMEZAWA Hiroyuki Acked-by: Balbir Singh Cc: Daisuke Nishimura Signed-off-by: Steven Rostedt --- mm/memcontrol.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 3508777..a164c93 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -718,6 +718,7 @@ static void __mem_cgroup_target_update(struct mem_cgroup *mem, int target) */ static void memcg_check_events(struct mem_cgroup *mem, struct page *page) { + preempt_disable(); /* threshold event is triggered in finer grain than soft limit */ if (unlikely(__memcg_event_check(mem, MEM_CGROUP_TARGET_THRESH))) { mem_cgroup_threshold(mem); @@ -737,6 +738,7 @@ static void memcg_check_events(struct mem_cgroup *mem, struct page *page) } #endif } + preempt_enable(); } static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) -- 1.7.5.4