From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750951AbXCHKki (ORCPT ); Thu, 8 Mar 2007 05:40:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750954AbXCHKkh (ORCPT ); Thu, 8 Mar 2007 05:40:37 -0500 Received: from smtp-out.google.com ([216.239.45.13]:45917 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750951AbXCHKkg (ORCPT ); Thu, 8 Mar 2007 05:40:36 -0500 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=received:message-id:date:from:to:subject:cc:in-reply-to: mime-version:content-type:content-transfer-encoding: content-disposition:references; b=VutxwUm16J4yBDPX62hqpnzZYf/PLKV8BV4hUKApQDJvdtz4OuF1m/DbvYnjnikHh edIlibi7EhKXHiwTKfZhQ== Message-ID: <6599ad830703080240o6f67df6cvab314c0cb4a3b5ff@mail.gmail.com> Date: Thu, 8 Mar 2007 02:40:30 -0800 From: "Paul Menage" To: vatsa@in.ibm.com Subject: Re: [ckrm-tech] [PATCH 1/7] containers (V7): Generic container system abstracted from cpusets code Cc: sekharan@us.ibm.com, ckrm-tech@lists.sourceforge.net, linux-kernel@vger.kernel.org, xemul@sw.ru, rohitseth@google.com, pj@sgi.com, ebiederm@xmission.com, mbligh@google.com, winget@google.com, containers@lists.osdl.org, serue@us.ibm.com, dev@sw.ru, devel@openvz.org In-Reply-To: <20070308103808.GH6504@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20070212081521.808338000@menage.corp.google.com> <20070212085104.130746000@menage.corp.google.com> <20070307122117.GB2336@in.ibm.com> <6599ad830703071250p6c92a357g51391a23ee3d78d8@mail.gmail.com> <20070308103808.GH6504@in.ibm.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 3/8/07, Srivatsa Vaddagiri wrote: > On Wed, Mar 07, 2007 at 12:50:03PM -0800, Paul Menage wrote: > > The callback mutex (which is what container_lock() actually locks) is > > also used to synchronize fork/exit against subsystem additions, in the > > event that some subsystem has registered fork or exit callbacks. We > > could probably have a separate subsystem_mutex for that instead. > > Why can't manage_mutex itself be used there (to serialize fork/exit callbacks > against modification to hierarchy)? Because manage_mutex can be held for very long periods of time. I think that a combination of a new lock that's only taken by fork/exit and register_subsys, plus task_lock (which prevents the current task from being moved) would be more lightweight. Paul