Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932478Ab0FQBvx (ORCPT ); Wed, 16 Jun 2010 21:51:53 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:47633 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759112Ab0FQBvk (ORCPT ); Wed, 16 Jun 2010 21:51:40 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Minchan Kim Subject: Re: [PATCH 3/9] oom: oom_kill_process() doesn't select kthread child Cc: kosaki.motohiro@jp.fujitsu.com, LKML , linux-mm , Andrew Morton , David Rientjes , KAMEZAWA Hiroyuki In-Reply-To: <20100616150232.GC9278@barrios-desktop> References: <20100616203126.72DD.A69D9226@jp.fujitsu.com> <20100616150232.GC9278@barrios-desktop> Message-Id: <20100617084154.FB33.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Thu, 17 Jun 2010 10:51:33 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1300 Lines: 32 > On Wed, Jun 16, 2010 at 08:32:08PM +0900, KOSAKI Motohiro wrote: > > Now, select_bad_process() have PF_KTHREAD check, but oom_kill_process > > doesn't. It mean oom_kill_process() may choose wrong task, especially, > > when the child are using use_mm(). > Now oom_kill_process is called by three place. > > 1. mem_cgroup_out_of_memory > 2. out_of_memory with sysctl_oom_kill_allocating_task > 3. out_of_memory with non-sysctl_oom_kill_allocating_task > > I think it's no problem in 1 and 3 since select_bad_process already checks > PF_KTHREAD. The problem in in 2. > So How about put the check before calling oom_kill_process in case of > sysctl_oom_kill_allocating task? > > if (sysctl_oom_kill_allocating_task) { > if (!current->flags & PF_KTHREAD) > oom_kill_process(); > > It can remove duplicated PF_KTHREAD check in select_bad_process and > oom_kill_process. This patch changed child selection logic. select_bad_process() doesn't check victim's child. IOW, this is necessary when all 1-3. -- 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/