From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932161Ab2CTPyK (ORCPT ); Tue, 20 Mar 2012 11:54:10 -0400 Received: from mail-gx0-f174.google.com ([209.85.161.174]:59826 "EHLO mail-gx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965076Ab2CTPyH (ORCPT ); Tue, 20 Mar 2012 11:54:07 -0400 Date: Tue, 20 Mar 2012 08:53:58 -0700 From: Tejun Heo To: Vivek Goyal Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org, ctalbott@google.com, rni@google.com Subject: Re: [PATCHSET] block: remove ioc_*_changed() Message-ID: <20120320155358.GB5684@google.com> References: <1332195059-2750-1-git-send-email-tj@kernel.org> <20120320155118.GC17071@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120320155118.GC17071@redhat.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 On Tue, Mar 20, 2012 at 11:51:18AM -0400, Vivek Goyal wrote: > So this patch still breaks cic->cfqq association in asynchronous > manner, when new request comes in. So it will still not solve the > problem I reported where after doing IO a task changes cgroup and > tries to delete the old cgroup and hangs forever as cic->cfqq is still > holding a reference to cgroup? That one is gonna have to be fixed from cgroup side. I already posted a RFC patchset (you were cc'd there, I think). At the moment, the blocking thing is memcg's ->pre_destroy() usage. I'll ping memcg people once more and if modification there isn't feasible, will implement a workaround in cgroup core. Thanks. -- tejun