From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752677AbcFURxb (ORCPT ); Tue, 21 Jun 2016 13:53:31 -0400 Received: from mail-lb0-f175.google.com ([209.85.217.175]:36706 "EHLO mail-lb0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751939AbcFURxa (ORCPT ); Tue, 21 Jun 2016 13:53:30 -0400 Date: Tue, 21 Jun 2016 19:46:17 +0200 From: Michal Hocko To: Tetsuo Handa Cc: linux-mm@kvack.org, rientjes@google.com, oleg@redhat.com, vdavydov@parallels.com, mgorman@techsingularity.net, hughd@google.com, riel@redhat.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: mm, oom_reaper: How to handle race with oom_killer_disable() ? Message-ID: <20160621174617.GA27527@dhcp22.suse.cz> References: <20160613111943.GB6518@dhcp22.suse.cz> <20160621083154.GA30848@dhcp22.suse.cz> <201606212003.FFB35429.QtMOJFFFOLSHVO@I-love.SAKURA.ne.jp> <20160621114643.GE30848@dhcp22.suse.cz> <20160621132736.GF30848@dhcp22.suse.cz> <201606220032.EGD09344.VOSQOMFJOLHtFF@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201606220032.EGD09344.VOSQOMFJOLHtFF@I-love.SAKURA.ne.jp> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 22-06-16 00:32:29, Tetsuo Handa wrote: > Michal Hocko wrote: [...] > > Hmm, what about the following instead. It is rather a workaround than a > > full flaged fix but it seems much more easier and shouldn't introduce > > new issues. > > Yes, I think that will work. But I think below patch (marking signal_struct > to ignore TIF_MEMDIE instead of clearing TIF_MEMDIE from task_struct) on top of > current linux.git will implement no-lockup requirement. No race is possible unlike > "[PATCH 10/10] mm, oom: hide mm which is shared with kthread or global init". Not really. Because without the exit_oom_victim from oom_reaper you have no guarantee that the oom_killer_disable will ever return. I have mentioned that in the changelog. There is simply no guarantee the oom victim will ever reach exit_mm->exit_oom_victim. -- Michal Hocko SUSE Labs