Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760763Ab2JaUOZ (ORCPT ); Wed, 31 Oct 2012 16:14:25 -0400 Received: from cantor2.suse.de ([195.135.220.15]:39631 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760737Ab2JaUOW (ORCPT ); Wed, 31 Oct 2012 16:14:22 -0400 Date: Wed, 31 Oct 2012 21:14:16 +0100 From: Michal Hocko To: Tejun Heo Cc: lizefan@huawei.com, hannes@cmpxchg.org, bsingharora@gmail.com, kamezawa.hiroyu@jp.fujitsu.com, containers@lists.linux-foundation.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/8] cgroup: kill cgroup_subsys->__DEPRECATED_clear_css_refs Message-ID: <20121031201415.GG1271@dhcp22.suse.cz> References: <1351712650-23709-1-git-send-email-tj@kernel.org> <1351712650-23709-2-git-send-email-tj@kernel.org> <20121031200859.GE1271@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1056 Lines: 27 On Wed 31-10-12 13:11:02, Tejun Heo wrote: > Hello, > > On Wed, Oct 31, 2012 at 1:08 PM, Michal Hocko wrote: > > local_irq_disable doesn't guarantee atomicity, because other CPUs will > > Maybe it should say atomicity on the local CPU. That would be more clear but being more verbose doesn't hurt either :P > > see the change in steps so this is a bit misleading. The real reason > > AFAICS is that we do not want to hang in css_tryget from IRQ context > > (does this really happen btw.?) which would interrupt cgroup_rmdir > > between we add CSS_DEACT_BIAS and the group is marked CGRP_REMOVED. > > Or am I still missing the point? > > Yeah, that's the correct one. We don't want tryget happening between > DEACT_BIAS and REMOVED as it can hang forever there. -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/