From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932360AbYB1VOZ (ORCPT ); Thu, 28 Feb 2008 16:14:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756383AbYB1VOP (ORCPT ); Thu, 28 Feb 2008 16:14:15 -0500 Received: from smtp-out.google.com ([216.239.33.17]:32119 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754345AbYB1VOO (ORCPT ); Thu, 28 Feb 2008 16:14:14 -0500 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=received:message-id:date:from:to:subject:cc:mime-version: content-type:content-transfer-encoding:content-disposition; b=o88xLjVz7ef083Y9jAleKpSq6ajZxm3eFBTQ0oi5AfQv0fYwHYorySk60ctfoBAiV hnK7WX6pT3qrXxxKksmPA== Message-ID: <6599ad830802281314s25c033d6tc021725ae28aef8d@mail.gmail.com> Date: Thu, 28 Feb 2008 13:14:05 -0800 From: "Paul Menage" To: "Linux Containers" , LKML , "Balbir Singh" , "Peter Zijlstra" , "Pavel Emelianov" , "Paul Jackson" Subject: [RFC] Prefixing cgroup generic control filenames with "cgroup." Cc: "Andrew Morton" MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org All control files created by cgroup subsystems are given a prefix corresponding to their subsystem name. But control files provided by cgroups itself have no prefix. Currently that set of files is just "tasks", "notify_on_release" and "release_agent", but that set is likely to expand in the future. To reduce the risk of clashes, it would make sense to prefix these files and any future ones with the "cgroup." prefix. The only reason that I can see *not* to do this would be for compatibility with 2.6.24. Do people think this is a strong enough reason to leave the existing names? If distros are planning to ship products based on 2.6.24, presumably they'd be adding their own patches anyway, so they could add a trivial prefix change patch too. (I realise this discussion would have been more useful *before* 2.6.24 shipped, but I didn't quite get round to it ...) A compromise might be to keep "tasks" unprefixed, and say that future names get the "cgroup." prefix; in this case I'd be inclined to add the prefix to notify_on_release and release_agent on the grounds that there's much less chance of breaking anyone with those files since (I suspect) they're much less used. Note that if you mount a cgroup filesystem with the "noprefix" option, which is what the cpuset filesystem wrapper does, no subsystems have prefixes, and in this case the "cgroup." prefix wouldn't be used either. So this doesn't affect any users that explicitly mount cpusets rather than cgroups. Thoughts? Paul