From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754926Ab2IMRsY (ORCPT ); Thu, 13 Sep 2012 13:48:24 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:38522 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752518Ab2IMRsW (ORCPT ); Thu, 13 Sep 2012 13:48:22 -0400 Date: Thu, 13 Sep 2012 10:48:17 -0700 From: Tejun Heo To: Glauber Costa Cc: linux-kernel@vger.kernel.org, Michal Hocko , 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" , Dave Jones , Lennart Poettering , Kay Sievers Subject: Re: [PATCH RFC cgroup/for-3.7] cgroup: mark subsystems with broken hierarchy support and whine if cgroups are nested for them Message-ID: <20120913174817.GA7677@google.com> References: <20120910223125.GC7677@google.com> <505055E5.90903@parallels.com> <20120912170357.GN7677@google.com> <5051C954.2080600@parallels.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5051C954.2080600@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 Thu, Sep 13, 2012 at 03:53:56PM +0400, Glauber Costa wrote: > Here is where the Kconfig option comes to play. If we do it in the > kernel, userspace doesn't have to do anything. I spoke with Lennart and > Kay, and at least from a systemd PoV, they would much rather not provide > a hack in userspace for a file that is scheduled to go away in any case > - which I personally believe is a fair request. > > It is a default, so the effect for the user is the same: After the > machine boots, use_hierarchy = 1, and he can still flip to 0 for some time. Alright, let's go Kconfig. Let's just make sure that the transitional nature is clearly labeled and the fact that the default config will generate a warning when nested cgroups are created in memcg. We can then coordinate the flip with distros. Can you please repost the Kconfig patch? > > Setting mark on a parent should be reflected on all its children w/o > > their own explicit settings. > > That is clear, and better behavior than we have today. What I mean, is > that by setting its own marking, the child can pretty much "escape" the > group. > > The ideal solution - from this point of view only - would be to have > more than one marking, and mark with all the way down to the root. So if > you have an iptables rule to match one marking, it still applies to the > kids. And you can still have extra markings. > > I am not sure this is feasible, though, in which case your solution > could be a good compromise. But please let's aim for it. I don't think it supports multiple tags. If that's possible, it would be nice but I don't think it's a must. Thanks. -- tejun