From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ee0-f44.google.com (mail-ee0-f44.google.com [74.125.83.44]) by kanga.kvack.org (Postfix) with ESMTP id 9B903900002 for ; Tue, 6 May 2014 09:29:49 -0400 (EDT) Received: by mail-ee0-f44.google.com with SMTP id c41so6499470eek.3 for ; Tue, 06 May 2014 06:29:49 -0700 (PDT) Received: from zene.cmpxchg.org (zene.cmpxchg.org. [2a01:238:4224:fa00:ca1f:9ef3:caee:a2bd]) by mx.google.com with ESMTPS id n46si13408718eeo.187.2014.05.06.06.29.47 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 06 May 2014 06:29:48 -0700 (PDT) Date: Tue, 6 May 2014 09:29:32 -0400 From: Johannes Weiner Subject: Re: [PATCH 1/4] memcg, mm: introduce lowlimit reclaim Message-ID: <20140506132932.GF19914@cmpxchg.org> References: <1398688005-26207-1-git-send-email-mhocko@suse.cz> <1398688005-26207-2-git-send-email-mhocko@suse.cz> <20140430225550.GD26041@cmpxchg.org> <20140502093628.GC3446@dhcp22.suse.cz> <20140502155805.GO23420@cmpxchg.org> <20140502164930.GP3446@dhcp22.suse.cz> <20140502220056.GP23420@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140502220056.GP23420@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andrew Morton , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Greg Thelen , Michel Lespinasse , Tejun Heo , Hugh Dickins , Roman Gushchin , LKML , linux-mm@kvack.org On Fri, May 02, 2014 at 06:00:56PM -0400, Johannes Weiner wrote: > On Fri, May 02, 2014 at 06:49:30PM +0200, Michal Hocko wrote: > > On Fri 02-05-14 11:58:05, Johannes Weiner wrote: > > > This is not even guarantees anymore, but rather another reclaim > > > prioritization scheme with best-effort semantics. That went over > > > horribly with soft limits, and I don't want to repeat this. > > > > > > Overcommitting on guarantees makes no sense, and you even agree you > > > are not interested in it. We also agree that we can always add a knob > > > later on to change semantics when an actual usecase presents itself, > > > so why not start with the clear and simple semantics, and the simpler > > > implementation? > > > > So you are really preferring an OOM instead? That was the original > > implementation posted at the end of last year and some people > > had concerns about it. This is the primary reason I came up with a > > weaker version which fallbacks rather than OOM. > > I'll dig through the archives on this then, thanks. The most recent discussion on this I could find was between you and Greg, where the final outcome was (excerpt): --- From: Greg Thelen To: Michal Hocko Cc: linux-mm@kvack.org, Johannes Weiner , Andrew Morton , KAMEZAWA Hiroyuki , LKML , Ying Han , Hugh Dickins , Michel Lespinasse , KOSAKI Motohiro , Tejun Heo Subject: Re: [RFC 0/4] memcg: Low-limit reclaim References: <1386771355-21805-1-git-send-email-mhocko@suse.cz> <20140130123044.GB13509@dhcp22.suse.cz> <20140203144341.GI2495@dhcp22.suse.cz> Date: Mon, 03 Feb 2014 17:33:13 -0800 Message-ID: List-ID: On Mon, Feb 03 2014, Michal Hocko wrote: > On Thu 30-01-14 16:28:27, Greg Thelen wrote: >> But this soft_limit,priority extension can be added later. > > Yes, I would like to have the strong semantic first and then deal with a > weaker form. Either by a new limit or a flag. Sounds good. --- So I think everybody involved in the discussions so far are preferring a hard guarantee, and then later, if needed, to either add a knob to make it a soft guarantee or to actually implement a usable soft limit. -- 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