From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx146.postini.com [74.125.245.146]) by kanga.kvack.org (Postfix) with SMTP id 7E8276B0033 for ; Mon, 22 Apr 2013 12:01:17 -0400 (EDT) Received: by mail-da0-f46.google.com with SMTP id y19so3204616dan.19 for ; Mon, 22 Apr 2013 09:01:16 -0700 (PDT) Date: Mon, 22 Apr 2013 09:01:12 -0700 From: Tejun Heo Subject: Re: memcg: softlimit on internal nodes Message-ID: <20130422160112.GE12543@htj.dyndns.org> References: <20130420002620.GA17179@mtj.dyndns.org> <20130420031611.GA4695@dhcp22.suse.cz> <20130421022321.GE19097@mtj.dyndns.org> <20130422042445.GA25089@mtj.dyndns.org> <20130422153730.GG18286@dhcp22.suse.cz> <20130422154620.GB12543@htj.dyndns.org> <20130422155454.GH18286@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130422155454.GH18286@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Michel Lespinasse , Johannes Weiner , Balbir Singh , KAMEZAWA Hiroyuki , cgroups@vger.kernel.org, linux-mm@kvack.org, Hugh Dickins , Ying Han , Glauber Costa , Greg Thelen Hey, On Mon, Apr 22, 2013 at 05:54:54PM +0200, Michal Hocko wrote: > > Oh, if so, I'm happy. Sorry about being brash on the thread; however, > > please talk with google memcg people. They have very different > > interpretation of what "softlimit" is and are using it according to > > that interpretation. If it *is* an actual soft limit, there is no > > inherent isolation coming from it and that should be clear to > > everyone. > > We have discussed that for a long time. I will not speak for Greg & Ying > but from my POV we have agreed that the current implementation will work > for them with some (minor) changes in their layout. > As I have said already with a careful configuration (e.i. setting the > soft limit only where it matters - where it protects an important > memory which is usually in the leaf nodes) you can actually achieve > _high_ probability for not being reclaimed after the rework which was not > possible before because of the implementation which was ugly and > smelled. I don't know. I'm not sure this is a good idea. It's still encouraging abuse of the knob even if that's not the intention and once the usage sticks you end up with something you can't revert afterwards. I think it'd be better to make it *very* clear that "softlimit" can't be used for isolation in any reliable way. Thanks. -- tejun -- 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