From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f200.google.com (mail-wr0-f200.google.com [209.85.128.200]) by kanga.kvack.org (Postfix) with ESMTP id A276C280415 for ; Wed, 6 Sep 2017 04:42:46 -0400 (EDT) Received: by mail-wr0-f200.google.com with SMTP id a47so6973089wra.0 for ; Wed, 06 Sep 2017 01:42:46 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id x7si2108517wrb.444.2017.09.06.01.42.45 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 06 Sep 2017 01:42:45 -0700 (PDT) Date: Wed, 6 Sep 2017 10:42:42 +0200 From: Michal Hocko Subject: Re: [v7 5/5] mm, oom: cgroup v2 mount option to disable cgroup-aware OOM killer Message-ID: <20170906084242.l4rcx6n3hdzxvil6@dhcp22.suse.cz> References: <20170904142108.7165-1-guro@fb.com> <20170904142108.7165-6-guro@fb.com> <20170905134412.qdvqcfhvbdzmarna@dhcp22.suse.cz> <20170905143021.GA28599@castle.dhcp.TheFacebook.com> <20170905151251.luh4wogjd3msfqgf@dhcp22.suse.cz> <20170905191609.GA19687@castle.dhcp.TheFacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170905191609.GA19687@castle.dhcp.TheFacebook.com> Sender: owner-linux-mm@kvack.org List-ID: To: Roman Gushchin Cc: linux-mm@kvack.org, Vladimir Davydov , Johannes Weiner , Tetsuo Handa , David Rientjes , Andrew Morton , Tejun Heo , kernel-team@fb.com, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org On Tue 05-09-17 20:16:09, Roman Gushchin wrote: > On Tue, Sep 05, 2017 at 05:12:51PM +0200, Michal Hocko wrote: [...] > > > Then we should probably hide corresponding > > > cgroup interface (oom_group and oom_priority knobs) by default, > > > and it feels as unnecessary complication and is overall against > > > cgroup v2 interface design. > > > > Why. If we care enough, we could simply return EINVAL when those knobs > > are written while the corresponding strategy is not used. > > It doesn't look as a nice default interface. I do not have a strong opinion on this. A printk_once could explain why the knob is ignored and instruct the admin how to enable the feature completely. > > > > I think we should instead go with > > > > oom_strategy=[alloc_task,biggest_task,cgroup] > > > > > > It would be a really nice interface; although I've no idea how to implement it: > > > "alloc_task" is an existing sysctl, which we have to preserve; > > > > I would argue that we should simply deprecate and later drop the sysctl. > > I _strongly_ suspect anybody is using this. If yes it is not that hard > > to change the kernel command like rather than select the sysctl. > > I agree. And if so, why do we need a new interface for an useless feature? Well, I won't be opposed just deprecating the sysfs and only add a "real" kill-allocate strategy if somebody explicitly asks for it. -- Michal Hocko SUSE Labs -- 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