From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f72.google.com (mail-pg0-f72.google.com [74.125.83.72]) by kanga.kvack.org (Postfix) with ESMTP id B0D786B054B for ; Tue, 1 Aug 2017 08:43:27 -0400 (EDT) Received: by mail-pg0-f72.google.com with SMTP id y129so16857595pgy.1 for ; Tue, 01 Aug 2017 05:43:27 -0700 (PDT) Received: from mx0a-00082601.pphosted.com (mx0b-00082601.pphosted.com. [67.231.153.30]) by mx.google.com with ESMTPS id x84si18391105pgx.426.2017.08.01.05.43.25 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 01 Aug 2017 05:43:26 -0700 (PDT) Date: Tue, 1 Aug 2017 13:42:38 +0100 From: Roman Gushchin Subject: Re: [PATCH 0/2] mm, oom: do not grant oom victims full memory reserves access Message-ID: <20170801124238.GA9497@castle.dhcp.TheFacebook.com> References: <20170727090357.3205-1-mhocko@kernel.org> <20170801121643.GI15774@dhcp22.suse.cz> <20170801122344.GA8457@castle.DHCP.thefacebook.com> <20170801122905.GL15774@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20170801122905.GL15774@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andrew Morton , David Rientjes , Johannes Weiner , Tetsuo Handa , linux-mm@kvack.org, LKML On Tue, Aug 01, 2017 at 02:29:05PM +0200, Michal Hocko wrote: > On Tue 01-08-17 13:23:44, Roman Gushchin wrote: > > On Tue, Aug 01, 2017 at 02:16:44PM +0200, Michal Hocko wrote: > > > On Thu 27-07-17 11:03:55, Michal Hocko wrote: > > > > Hi, > > > > this is a part of a larger series I posted back in Oct last year [1]. I > > > > have dropped patch 3 because it was incorrect and patch 4 is not > > > > applicable without it. > > > > > > > > The primary reason to apply patch 1 is to remove a risk of the complete > > > > memory depletion by oom victims. While this is a theoretical risk right > > > > now there is a demand for memcg aware oom killer which might kill all > > > > processes inside a memcg which can be a lot of tasks. That would make > > > > the risk quite real. > > > > > > > > This issue is addressed by limiting access to memory reserves. We no > > > > longer use TIF_MEMDIE to grant the access and use tsk_is_oom_victim > > > > instead. See Patch 1 for more details. Patch 2 is a trivial follow up > > > > cleanup. > > > > > > Any comments, concerns? Can we merge it? > > > > I've rebased the cgroup-aware OOM killer and ran some tests. > > Everything works well. > > Thanks for your testing. Can I assume your Tested-by? Sure. I wonder if we can get rid of TIF_MEMDIE completely, if we will count OOM victims on per-oom-victim-signal-struct rather than on per-thread basis? Say, assign oom_mm using cmpxchg, and call exit_oom_victim() from __exit_signal()? __thaw_task() can be called from mark_oom_victim() unconditionally. Do you see any problems with this approach? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org