From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423627AbcBQOsi (ORCPT ); Wed, 17 Feb 2016 09:48:38 -0500 Received: from mail-wm0-f51.google.com ([74.125.82.51]:38016 "EHLO mail-wm0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423553AbcBQOsg (ORCPT ); Wed, 17 Feb 2016 09:48:36 -0500 Date: Wed, 17 Feb 2016 15:48:34 +0100 From: Michal Hocko To: Tetsuo Handa Cc: akpm@linux-foundation.org, rientjes@google.com, mgorman@suse.de, oleg@redhat.com, torvalds@linux-foundation.org, hughd@google.com, andrea@kernel.org, riel@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm,oom: exclude oom_task_origin processes if they are OOM-unkillable. Message-ID: <20160217144834.GQ29196@dhcp22.suse.cz> References: <1455719460-7690-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1455719460-7690-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 17-02-16 23:31:00, Tetsuo Handa wrote: > oom_scan_process_thread() returns OOM_SCAN_SELECT when there is a > thread which returns oom_task_origin() == true. But it is possible > that such thread is marked as OOM-unkillable. In that case, the OOM > killer must not select such process. As already pointed out swapoff or ksm run_store are the only users of OOM_FLAG_ORIGIN and it would be insane to run them from an oom disabled context. So I wouldn't care much about this part that much and consider the patch to be more of a cleanup rather than a bug fix. > Since it is meaningless to return OOM_SCAN_OK for OOM-unkillable > process because subsequent oom_badness() call will return 0, this > patch changes oom_scan_process_thread to return OOM_SCAN_CONTINUE > if that process is marked as OOM-unkillable (regardless of > oom_task_origin()). > > Signed-off-by: Tetsuo Handa > Suggested-by: Michal Hocko Acked-by: Michal Hocko > --- > mm/oom_kill.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index 7653055..cf87153 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -282,7 +282,7 @@ enum oom_scan_t oom_scan_process_thread(struct oom_control *oc, > if (!is_sysrq_oom(oc)) > return OOM_SCAN_ABORT; > } > - if (!task->mm) > + if (!task->mm || task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) > return OOM_SCAN_CONTINUE; > > /* > -- > 1.8.3.1 -- Michal Hocko SUSE Labs