From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755657Ab2IEIOs (ORCPT ); Wed, 5 Sep 2012 04:14:48 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:49178 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751164Ab2IEIOp (ORCPT ); Wed, 5 Sep 2012 04:14:45 -0400 Date: Wed, 5 Sep 2012 01:14:39 -0700 From: Tejun Heo To: Glauber Costa Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, davej@redhat.com, ben@decadent.org.uk, a.p.zijlstra@chello.nl, pjt@google.com, lennart@poettering.net, kay.sievers@vrfy.org Subject: Re: [RFC 0/5] forced comounts for cgroups. Message-ID: <20120905081439.GC3195@dhcp-172-17-108-109.mtv.corp.google.com> References: <1346768300-10282-1-git-send-email-glommer@parallels.com> <20120904214602.GA9092@dhcp-172-17-108-109.mtv.corp.google.com> <5047074D.1030104@parallels.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5047074D.1030104@parallels.com> 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, Glauber. On Wed, Sep 05, 2012 at 12:03:25PM +0400, Glauber Costa wrote: > The goal here is to have distributions to do it, because they tend to > have a well defined lifecycle management, much more than upstream. Whoever > sets this option, can coordinate with upstream. Distros can just co-mount them during boot. What's the point of the config options? > > Also, I really don't see much point in enforcing this almost arbitrary > > grouping of controllers. It doesn't simplify anything and using > > cpuacct in more granular way than cpu actually is one of the better > > justified use of multiple hierarchies. Also, what about memcg and > > blkcg? Do they *really* coincide? Note that both blkcg and memcg > > involve non-trivial overhead and blkcg is essentially broken > > hierarchy-wise. > > Where did I mention memcg or blkcg in this patch ? Differing hierarchies in memcg and blkcg currently is the most prominent case where the intersection in writeback is problematic and your proposed solution doesn't help one way or the other. What's the point? Thanks. -- tejun