From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756164Ab2HUKAX (ORCPT ); Tue, 21 Aug 2012 06:00:23 -0400 Received: from cantor2.suse.de ([195.135.220.15]:34757 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756129Ab2HUKAL (ORCPT ); Tue, 21 Aug 2012 06:00:11 -0400 Date: Tue, 21 Aug 2012 12:00:07 +0200 From: Michal Hocko To: Glauber Costa Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, devel@openvz.org, Johannes Weiner , Andrew Morton , kamezawa.hiroyu@jp.fujitsu.com, Christoph Lameter , David Rientjes , Pekka Enberg , Pekka Enberg , Suleiman Souhlal Subject: Re: [PATCH v2 09/11] memcg: propagate kmem limiting information to children Message-ID: <20120821100007.GE19797@dhcp22.suse.cz> References: <1344517279-30646-1-git-send-email-glommer@parallels.com> <1344517279-30646-10-git-send-email-glommer@parallels.com> <20120817090005.GC18600@dhcp22.suse.cz> <502E0BC3.8090204@parallels.com> <20120817093504.GE18600@dhcp22.suse.cz> <502E17C4.7060204@parallels.com> <20120817103550.GF18600@dhcp22.suse.cz> <502E1E90.1080805@parallels.com> <20120821075430.GA19797@dhcp22.suse.cz> <50335341.6010400@parallels.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50335341.6010400@parallels.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 21-08-12 13:22:09, Glauber Costa wrote: > On 08/21/2012 11:54 AM, Michal Hocko wrote: [...] > > But maybe you have a good use case for that? > > > Honestly, I don't. For my particular use case, this would be always on, > and end of story. I was operating under the belief that being able to > say "Oh, I regret", and then turning it off would be beneficial, even at > the expense of the - self contained - complication. > > For the general sanity of the interface, it is also a bit simpler to say > "if kmem is unlimited, x happens", which is a verifiable statement, than > to have a statement that is dependent on past history. OK, fair point. We shouldn't rely on the history. Maybe memory.kmem.limit_in_bytes could return some special value like -1 in such a case? > But all of those need of course, as you pointed out, to be traded off > by the code complexity. > > I am fine with either, I just need a clear sign from you guys so I don't > keep deimplementing and reimplementing this forever. I would be for make it simple now and go with additional features later when there is a demand for them. Maybe we will have runtimg switch for user memory accounting as well one day. But let's see what others think? -- Michal Hocko SUSE Labs