From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752020AbdIRGQJ (ORCPT ); Mon, 18 Sep 2017 02:16:09 -0400 Received: from mx2.suse.de ([195.135.220.15]:45317 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751704AbdIRGQI (ORCPT ); Mon, 18 Sep 2017 02:16:08 -0400 Date: Mon, 18 Sep 2017 08:16:03 +0200 From: Michal Hocko To: David Rientjes Cc: Roman Gushchin , linux-mm@kvack.org, Vladimir Davydov , Johannes Weiner , Tetsuo Handa , Andrew Morton , Tejun Heo , kernel-team@fb.com, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [v8 0/4] cgroup-aware OOM killer Message-ID: <20170918061603.z2ngh6bs5276mc3q@dhcp22.suse.cz> References: <20170911131742.16482-1-guro@fb.com> <20170913122914.5gdksbmkolum7ita@dhcp22.suse.cz> <20170913215607.GA19259@castle> <20170914134014.wqemev2kgychv7m5@dhcp22.suse.cz> <20170914160548.GA30441@castle> <20170915105826.hq5afcu2ij7hevb4@dhcp22.suse.cz> <20170915152301.GA29379@castle> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 15-09-17 12:55:55, David Rientjes wrote: > On Fri, 15 Sep 2017, Roman Gushchin wrote: > > > > But then you just enforce a structural restriction on your configuration > > > because > > > root > > > / \ > > > A D > > > /\ > > > B C > > > > > > is a different thing than > > > root > > > / | \ > > > B C D > > > > > > > I actually don't have a strong argument against an approach to select > > largest leaf or kill-all-set memcg. I think, in practice there will be > > no much difference. > > > > The only real concern I have is that then we have to do the same with > > oom_priorities (select largest priority tree-wide), and this will limit > > an ability to enforce the priority by parent cgroup. > > > > Yes, oom_priority cannot select the largest priority tree-wide for exactly > that reason. We need the ability to control from which subtree the kill > occurs in ancestor cgroups. If multiple jobs are allocated their own > cgroups and they can own memory.oom_priority for their own subcontainers, > this becomes quite powerful so they can define their own oom priorities. > Otherwise, they can easily override the oom priorities of other cgroups. Could you be more speicific about your usecase? What would be a problem If we allow to only increase priority in children (like other hierarchical controls). -- Michal Hocko SUSE Labs