Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751076AbZKYFmg (ORCPT ); Wed, 25 Nov 2009 00:42:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750816AbZKYFmf (ORCPT ); Wed, 25 Nov 2009 00:42:35 -0500 Received: from TYO201.gate.nec.co.jp ([202.32.8.193]:43449 "EHLO tyo201.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750813AbZKYFme (ORCPT ); Wed, 25 Nov 2009 00:42:34 -0500 Date: Wed, 25 Nov 2009 14:32:18 +0900 From: Daisuke Nishimura To: KAMEZAWA Hiroyuki Cc: stable , LKML , linux-mm , Andrew Morton , Balbir Singh , David Rientjes , KOSAKI Motohiro , Daisuke Nishimura Subject: [BUGFIX][PATCH v2 -stable] memcg: avoid oom-killing innocent task in case of use_hierarchy Message-Id: <20091125143218.96156a5f.nishimura@mxp.nes.nec.co.jp> In-Reply-To: <20091125090050.e366dca5.kamezawa.hiroyu@jp.fujitsu.com> References: <20091124145759.194cfc9f.nishimura@mxp.nes.nec.co.jp> <20091124162854.fb31e81e.nishimura@mxp.nes.nec.co.jp> <20091125090050.e366dca5.kamezawa.hiroyu@jp.fujitsu.com> Organization: NEC Soft, Ltd. X-Mailer: Sylpheed 2.6.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2825 Lines: 78 > Hmm. Maybe not-expected behavior...could you add comment ? > How about this ? > Acked-by: KAMEZAWA Hiroyuki > (*) I'm sorry I can't work enough in these days. > BTW, this patch conflict with oom-dump-stack-and-vm-state-when-oom-killer-panics.patch in current mmotm(that's why I post mmotm version separately), so this bug will not be fixed till 2.6.33 in linus-tree. So I think this patch should go in 2.6.32.y too. === 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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/