From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ua0-f200.google.com (mail-ua0-f200.google.com [209.85.217.200]) by kanga.kvack.org (Postfix) with ESMTP id B07516B0253 for ; Tue, 12 Sep 2017 16:01:43 -0400 (EDT) Received: by mail-ua0-f200.google.com with SMTP id c27so8302926uah.1 for ; Tue, 12 Sep 2017 13:01:43 -0700 (PDT) Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com. [67.231.145.42]) by mx.google.com with ESMTPS id c27si6464793uaa.173.2017.09.12.13.01.41 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 12 Sep 2017 13:01:42 -0700 (PDT) Date: Tue, 12 Sep 2017 21:01:15 +0100 From: Roman Gushchin Subject: Re: [v8 3/4] mm, oom: add cgroup v2 mount option for cgroup-aware OOM killer Message-ID: <20170912200115.GA25218@castle> References: <20170911131742.16482-1-guro@fb.com> <20170911131742.16482-4-guro@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: linux-mm@kvack.org, Michal Hocko , 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 On Mon, Sep 11, 2017 at 01:48:39PM -0700, David Rientjes wrote: > On Mon, 11 Sep 2017, Roman Gushchin wrote: > > > Add a "groupoom" cgroup v2 mount option to enable the cgroup-aware > > OOM killer. If not set, the OOM selection is performed in > > a "traditional" per-process way. > > > > The behavior can be changed dynamically by remounting the cgroupfs. > > I can't imagine that Tejun would be happy with a new mount option, > especially when it's not required. > > OOM behavior does not need to be defined at mount time and for the entire > hierarchy. It's possible to very easily implement a tunable as part of > mem cgroup that is propagated to descendants and controls the oom scoring > behavior for that hierarchy. It does not need to be system wide and > affect scoring of all processes based on which mem cgroup they are > attached to at any given time. No, I don't think that mixing per-cgroup and per-process OOM selection algorithms is a good idea. So, there are 3 reasonable options: 1) boot option 2) sysctl 3) cgroup mount option I believe, 3) is better, because it allows changing the behavior dynamically, and explicitly depends on v2 (what sysctl lacks). So, the only question is should it be opt-in or opt-out option. Personally, I would prefer opt-out, but Michal has a very strong opinion here. Thanks! -- 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