From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id E31036B0044 for ; Wed, 16 Dec 2009 19:58:02 -0500 (EST) Date: Thu, 17 Dec 2009 09:47:24 +0900 From: Daisuke Nishimura Subject: [BUGFIX][PATCH v2 -stable] memcg: avoid oom-killing innocent task in case of use_hierarchy Message-Id: <20091217094724.15ec3b27.nishimura@mxp.nes.nec.co.jp> In-Reply-To: <20091125143218.96156a5f.nishimura@mxp.nes.nec.co.jp> References: <20091124145759.194cfc9f.nishimura@mxp.nes.nec.co.jp> <20091124162854.fb31e81e.nishimura@mxp.nes.nec.co.jp> <20091125090050.e366dca5.kamezawa.hiroyu@jp.fujitsu.com> <20091125143218.96156a5f.nishimura@mxp.nes.nec.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: stable Cc: LKML , linux-mm , Andrew Morton , Balbir Singh , David Rientjes , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Daisuke Nishimura List-ID: Stable team. Cay you pick this up for 2.6.32.y(and 2.6.31.y if it will be released) ? This is a for-stable version of a bugfix patch that corresponds to the upstream commmit d31f56dbf8bafaacb0c617f9a6f137498d5c7aed. === From: Daisuke Nishimura task_in_mem_cgroup(), which is called by select_bad_process() to check whether a task can be a candidate for being oom-killed from memcg's limit, checks "curr->use_hierarchy"("curr" is the mem_cgroup the task belongs to). But this check return true(it's false positive) when: /00 use_hierarchy == 0 <- hitting limit /00/aa use_hierarchy == 1 <- "curr" This leads to killing an innocent task in 00/aa. This patch is a fix for this bug. And this patch also fixes the arg for mem_cgroup_print_oom_info(). We should print information of mem_cgroup which the task being killed, not current, belongs to. Signed-off-by: Daisuke Nishimura Acked-by: KAMEZAWA Hiroyuki Reviewed-by: Balbir Singh --- mm/memcontrol.c | 8 +++++++- mm/oom_kill.c | 2 +- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index fd4529d..566925e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -496,7 +496,13 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) task_unlock(task); if (!curr) return 0; - if (curr->use_hierarchy) + /* + * We should check use_hierarchy of "mem" not "curr". Because checking + * use_hierarchy of "curr" here make this function true if hierarchy is + * enabled in "curr" and "curr" is a child of "mem" in *cgroup* + * hierarchy(even if use_hierarchy is disabled in "mem"). + */ + if (mem->use_hierarchy) ret = css_is_ancestor(&curr->css, &mem->css); else ret = (curr == mem); diff --git a/mm/oom_kill.c b/mm/oom_kill.c index a7b2460..ed452e9 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -400,7 +400,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, cpuset_print_task_mems_allowed(current); task_unlock(current); dump_stack(); - mem_cgroup_print_oom_info(mem, current); + mem_cgroup_print_oom_info(mem, p); show_mem(); if (sysctl_oom_dump_tasks) dump_tasks(mem); -- 1.5.6.1 -- 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