From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber Costa Subject: Re: [PATCH v2] memcg: first step towards hierarchical controller Date: Tue, 4 Sep 2012 12:29:42 +0400 Message-ID: <5045BBF6.5000900@parallels.com> References: <1346687211-31848-1-git-send-email-glommer@parallels.com> <20120903164148.GS29217@decadent.org.uk> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120903164148.GS29217-/+tVBieCtBitmTQ+vhA3Yw@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Ben Hutchings Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Dave Jones , Peter Zijlstra , Paul Turner , Lennart Poettering , Kay Sievers , Michal Hocko , Kamezawa Hiroyuki , Johannes Weiner , Tejun Heo > >> + of the root memcg, regardless of their positioning in the tree. >> + >> + Use of flat hierarchies is highly discouraged, but has been the >> + default for performance reasons for quite some time. Setting this flag >> + to on will make hierarchical accounting the default. It is still >> + possible to set it back to flat by writing 0 to the file >> + memory.use_hierarchy, albeit discouraged. Distributors are encouraged >> + to set this option. > [...] > > I don't think that 'default n' is effective encouragement! > > Ben. > If it were up to me, I would just flip it to 1. No option. A bit of history here, is that people have a - quite valid - concern that this will disrupt users using their own kernel, should they decide to update, recompile and run. Conditional on a Kconfig option, people reusing their .config will see no change. Distros, otoh, are versioned. It is not unreasonable to expect a behavior change when a major version flips. The encouragement here comes not from the default, but from the acknowledgment that his thing is totally broken, and we need to act to fix it in a compatible way. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx206.postini.com [74.125.245.206]) by kanga.kvack.org (Postfix) with SMTP id AF8B36B005D for ; Tue, 4 Sep 2012 04:33:12 -0400 (EDT) Message-ID: <5045BBF6.5000900@parallels.com> Date: Tue, 4 Sep 2012 12:29:42 +0400 From: Glauber Costa MIME-Version: 1.0 Subject: Re: [PATCH v2] memcg: first step towards hierarchical controller References: <1346687211-31848-1-git-send-email-glommer@parallels.com> <20120903164148.GS29217@decadent.org.uk> In-Reply-To: <20120903164148.GS29217@decadent.org.uk> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Ben Hutchings Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, Dave Jones , Peter Zijlstra , Paul Turner , Lennart Poettering , Kay Sievers , Michal Hocko , Kamezawa Hiroyuki , Johannes Weiner , Tejun Heo > >> + of the root memcg, regardless of their positioning in the tree. >> + >> + Use of flat hierarchies is highly discouraged, but has been the >> + default for performance reasons for quite some time. Setting this flag >> + to on will make hierarchical accounting the default. It is still >> + possible to set it back to flat by writing 0 to the file >> + memory.use_hierarchy, albeit discouraged. Distributors are encouraged >> + to set this option. > [...] > > I don't think that 'default n' is effective encouragement! > > Ben. > If it were up to me, I would just flip it to 1. No option. A bit of history here, is that people have a - quite valid - concern that this will disrupt users using their own kernel, should they decide to update, recompile and run. Conditional on a Kconfig option, people reusing their .config will see no change. Distros, otoh, are versioned. It is not unreasonable to expect a behavior change when a major version flips. The encouragement here comes not from the default, but from the acknowledgment that his thing is totally broken, and we need to act to fix it in a compatible way. -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754700Ab2IDIdH (ORCPT ); Tue, 4 Sep 2012 04:33:07 -0400 Received: from mx2.parallels.com ([64.131.90.16]:38537 "EHLO mx2.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753915Ab2IDIdF (ORCPT ); Tue, 4 Sep 2012 04:33:05 -0400 Message-ID: <5045BBF6.5000900@parallels.com> Date: Tue, 4 Sep 2012 12:29:42 +0400 From: Glauber Costa User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120828 Thunderbird/15.0 MIME-Version: 1.0 To: Ben Hutchings CC: , , , Dave Jones , Peter Zijlstra , Paul Turner , Lennart Poettering , Kay Sievers , Michal Hocko , Kamezawa Hiroyuki , Johannes Weiner , Tejun Heo Subject: Re: [PATCH v2] memcg: first step towards hierarchical controller References: <1346687211-31848-1-git-send-email-glommer@parallels.com> <20120903164148.GS29217@decadent.org.uk> In-Reply-To: <20120903164148.GS29217@decadent.org.uk> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > >> + of the root memcg, regardless of their positioning in the tree. >> + >> + Use of flat hierarchies is highly discouraged, but has been the >> + default for performance reasons for quite some time. Setting this flag >> + to on will make hierarchical accounting the default. It is still >> + possible to set it back to flat by writing 0 to the file >> + memory.use_hierarchy, albeit discouraged. Distributors are encouraged >> + to set this option. > [...] > > I don't think that 'default n' is effective encouragement! > > Ben. > If it were up to me, I would just flip it to 1. No option. A bit of history here, is that people have a - quite valid - concern that this will disrupt users using their own kernel, should they decide to update, recompile and run. Conditional on a Kconfig option, people reusing their .config will see no change. Distros, otoh, are versioned. It is not unreasonable to expect a behavior change when a major version flips. The encouragement here comes not from the default, but from the acknowledgment that his thing is totally broken, and we need to act to fix it in a compatible way.