From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) by kanga.kvack.org (Postfix) with ESMTP id D8FF86B000D for ; Mon, 23 Jul 2018 17:29:17 -0400 (EDT) Received: by mail-ed1-f72.google.com with SMTP id o60-v6so887330edd.13 for ; Mon, 23 Jul 2018 14:29:17 -0700 (PDT) Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com. [67.231.145.42]) by mx.google.com with ESMTPS id v27-v6si5706148eda.162.2018.07.23.14.29.16 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 23 Jul 2018 14:29:16 -0700 (PDT) Date: Mon, 23 Jul 2018 14:28:58 -0700 From: Roman Gushchin Subject: Re: [patch v3 -mm 3/6] mm, memcg: add hierarchical usage oom policy Message-ID: <20180723212855.GA25062@castle> References: <20180716181613.GA28327@castle> 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: Andrew Morton , Michal Hocko , Vladimir Davydov , Johannes Weiner , Tejun Heo , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org On Mon, Jul 23, 2018 at 01:33:19PM -0700, David Rientjes wrote: > On Mon, 16 Jul 2018, David Rientjes wrote: > > > > And "tree" is different. It actually changes how the selection algorithm works, > > > and sub-tree settings do matter in this case. > > > > > > > "Tree" is considering the entity as a single indivisible memory consumer, > > it is compared with siblings based on its hierarhical usage. It has > > cgroup oom policy. > > > > It would be possible to separate this out, if you'd prefer, to account > > an intermediate cgroup as the largest descendant or the sum of all > > descendants. I hadn't found a usecase for that, however, but it doesn't > > mean there isn't one. If you'd like, I can introduce another tunable. > > > > Roman, I'm trying to make progress so that the cgroup aware oom killer is > in a state that it can be merged. Would you prefer a second tunable here > to specify a cgroup's points includes memory from its subtree? Hi, David! It's hard to tell, because I don't have a clear picture of what you're suggesting now. My biggest concern about your last version was that it's hard to tell what oom_policy really defines. Each value has it's own application rules, which is a bit messy (some values are meaningful for OOMing cgroup only, other are reading on hierarchy traversal). If you know how to make it clear and non-contradictory, please, describe the proposed interface. > > It would be helpful if you would also review the rest of the patchset. I think, that we should focus on interface semantics right now. If we can't agree on how the things should work, it makes no sense to discuss the implementation. Thanks!