From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH REPOST RFC cgroup/for-3.7] cgroup: mark subsystems with broken hierarchy support and whine if cgroups are nested for them Date: Wed, 12 Sep 2012 09:41:02 -0700 Message-ID: <20120912164102.GM7677@google.com> References: <20120910223125.GC7677@google.com> <20120910223355.GD7677@google.com> <20120911100433.GC8058@dhcp22.suse.cz> <20120911170746.GL7677@google.com> <20120912154745.GV21579@dhcp22.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=FJ+Db1zIN/ZmW1Yz2rhK6RA+qTAxVkpferpM+k8nPBU=; b=wm/29lVhdRaDIl9yvkgULeS23b0EYQmuhh6LdFMC9yDueemj4WX4T/64HA5dhCIcAN cNrptm84+uTFv60jW8OL+b/xxisNqOOkFAue5K2zNdxB3vw+Y/YWJik7s3Lfo1C5F/r0 ZiKURYvlvcHB0g22VjbtgXM3be1hC3v9cil8agb1DXKe8onTTjfuuJTPqwrIcOpckUpX 7EiaS5Uz1wvZ4dH5q9hEE4USvcnKh/IprOb83IJN99a9m6p0i+FA720ilRu6x1j2OO3x JuS156EyrJY8RHMbM6mEPUxbGdov1QEH1FXO4/yhCSD/umwSkEItw1NLOV0eily33Z28 Oa+Q== Content-Disposition: inline In-Reply-To: <20120912154745.GV21579-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Michal Hocko Cc: Neil Horman , "Serge E. Hallyn" , containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Paul Mackerras , "Aneesh Kumar K.V" , Arnaldo Carvalho de Melo , Johannes Weiner , Thomas Graf , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Paul Turner , Ingo Molnar , Vivek Goyal Hello, On Wed, Sep 12, 2012 at 05:47:45PM +0200, Michal Hocko wrote: > > If it's absolutely necessary, I think it should be a root-only flag > > (even if that ends up using the same code path). Eventually, we > > really want to kill .use_hierarchy, or at least make it to RO 1. As > > it's currently defined, it's just way too confusing. > > Agreed on that, definitely. The thing is that if we're gonna be headed that way, we're gonna have to nudge people to .use_hierarchy = 1 everywher first. If .use_hierarchy = 0 at root is a valid use case which absolutedly needs to be maintained (from what I read, I don't think it is), let's move it to a different root-only flag; otherwise, it should be phased out. As such, while the user might not be necessarily wrong, we still need to unify the behavior, I think. Thanks. -- tejun From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760457Ab2ILQlM (ORCPT ); Wed, 12 Sep 2012 12:41:12 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:39535 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760460Ab2ILQlH (ORCPT ); Wed, 12 Sep 2012 12:41:07 -0400 Date: Wed, 12 Sep 2012 09:41:02 -0700 From: Tejun Heo To: Michal Hocko Cc: linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, cgroups@vger.kernel.org, Li Zefan , Glauber Costa , 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: <20120912164102.GM7677@google.com> References: <20120910223125.GC7677@google.com> <20120910223355.GD7677@google.com> <20120911100433.GC8058@dhcp22.suse.cz> <20120911170746.GL7677@google.com> <20120912154745.GV21579@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120912154745.GV21579@dhcp22.suse.cz> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Wed, Sep 12, 2012 at 05:47:45PM +0200, Michal Hocko wrote: > > If it's absolutely necessary, I think it should be a root-only flag > > (even if that ends up using the same code path). Eventually, we > > really want to kill .use_hierarchy, or at least make it to RO 1. As > > it's currently defined, it's just way too confusing. > > Agreed on that, definitely. The thing is that if we're gonna be headed that way, we're gonna have to nudge people to .use_hierarchy = 1 everywher first. If .use_hierarchy = 0 at root is a valid use case which absolutedly needs to be maintained (from what I read, I don't think it is), let's move it to a different root-only flag; otherwise, it should be phased out. As such, while the user might not be necessarily wrong, we still need to unify the behavior, I think. Thanks. -- tejun