From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754713Ab1HZM7f (ORCPT ); Fri, 26 Aug 2011 08:59:35 -0400 Received: from cantor2.suse.de ([195.135.220.15]:40382 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754515Ab1HZM7b (ORCPT ); Fri, 26 Aug 2011 08:59:31 -0400 Date: Fri, 26 Aug 2011 14:59:28 +0200 From: Michal Hocko To: Konstantin Khlebnikov Cc: David Rientjes , Oleg Nesterov , "linux-mm@kvack.org" , Andrew Morton , "linux-kernel@vger.kernel.org" , KOSAKI Motohiro , KAMEZAWA Hiroyuki , "Rafael J. Wysocki" Subject: Re: [PATCH] oom: skip frozen tasks Message-ID: <20110826125928.GE9083@tiehlicka.suse.cz> References: <20110825091920.GA22564@tiehlicka.suse.cz> <20110825151818.GA4003@redhat.com> <20110825164758.GB22564@tiehlicka.suse.cz> <20110826070946.GA7280@tiehlicka.suse.cz> <20110826085610.GA9083@tiehlicka.suse.cz> <4E576F65.5060009@openvz.org> <20110826104827.GC9083@tiehlicka.suse.cz> <4E579541.6060607@openvz.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E579541.6060607@openvz.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 26-08-11 16:44:49, Konstantin Khlebnikov wrote: > Michal Hocko wrote: > >On Fri 26-08-11 14:03:17, Konstantin Khlebnikov wrote: > >>Michal Hocko wrote: > >> > >>>@@ -450,6 +459,10 @@ static int oom_kill_task(struct task_struct *p, struct mem_cgroup *mem) > >>> pr_err("Kill process %d (%s) sharing same memory\n", > >>> task_pid_nr(q), q->comm); > >>> task_unlock(q); > >>>+ > >>>+ if (frozen(q)) > >>>+ thaw_process(q); > >>>+ > >> > >>We must thaw task strictly after sending SIGKILL. > > > >Sounds reasonable. > > > >>But anyway I think this is a bad idea. > > > >Why? > > Refrigerator may be used for digging in task's internal structures, > so such digger may be very surprised if somebody suddenly thaws this task. That is something similar why I mentioned that we probably want to give it some oom bonus. Nevertheless we have to be carefull about that. Someone could freeze a memory hog just to hide it from OOM which would have much worse consequences than if such app disappeared while somebody is looking at it while it is frozen. This has to be balanced somehow. > > > > >> > >>> force_sig(SIGKILL, q); > >>> } > >>> > > > > -- > 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/ -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic