From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753644Ab2IMRkM (ORCPT ); Thu, 13 Sep 2012 13:40:12 -0400 Received: from cantor2.suse.de ([195.135.220.15]:34743 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752135Ab2IMRkJ (ORCPT ); Thu, 13 Sep 2012 13:40:09 -0400 Date: Thu, 13 Sep 2012 19:39:58 +0200 From: Michal Hocko To: Tejun Heo Cc: Glauber Costa , linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, cgroups@vger.kernel.org, Li Zefan , Peter Zijlstra , Paul Turner , Johannes Weiner , Thomas Graf , "Serge E. Hallyn" , Vivek Goyal , Paul Mackerras , Ingo Molnar , Arnaldo Carvalho de Melo , Neil Horman , "Aneesh Kumar K.V" Subject: Re: [PATCH REPOST RFC cgroup/for-3.7] cgroup: mark subsystems with broken hierarchy support and whine if cgroups are nested for them Message-ID: <20120913173958.GA21381@dhcp22.suse.cz> References: <20120910223125.GC7677@google.com> <20120910223355.GD7677@google.com> <20120911100433.GC8058@dhcp22.suse.cz> <5050568B.9090601@parallels.com> <20120912154907.GW21579@dhcp22.suse.cz> <20120912171120.GP7677@google.com> <20120913121438.GC8055@dhcp22.suse.cz> <20120913171832.GY7677@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120913171832.GY7677@google.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 Thu 13-09-12 10:18:32, Tejun Heo wrote: > Hello, Michal. > > On Thu, Sep 13, 2012 at 02:14:38PM +0200, Michal Hocko wrote: > > I would like to see use_hierarchy go away. The only concern I have is > > to warn only if somebody is doing something wrong (aka flat > > hierarchies). Or better put it this way. Do not warn in cases which do > > not change if use_hierarchy is gone or default changes to 1. > > An example: > > root (use_hierarchy=0) > > | \ > > | A (use_hierarchy=0) > > | > > B (use_hierarachy=1) > > |\ > > C D > > > > is a perfectly sane configuration and I do not see any reason to fill > > logs with some scary warnings when A is created. There will be no > > semantical change in this setup When use_hierchy is gone. > > > > So the only thing I am proposing here is to warn only if something > > should be fixed in the configuration in order to be prepared for fully > > hierarchical (and that is a second level of children from root with > > use_hierachy==0). > > > > Does it make more sense now? > > Ah, okay, so what you're saying is that we shouldn't warn if 0 > .use_hierarchys don't make any behavior difference from when they're > all 1, right? Exactly. 1st level of children under the root is exactly this kind of setup. > If so, I have no objection. Will incorporate your updated version. Thanks! -- Michal Hocko SUSE Labs