From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756913Ab1JTRwM (ORCPT ); Thu, 20 Oct 2011 13:52:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51726 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756141Ab1JTRwL (ORCPT ); Thu, 20 Oct 2011 13:52:11 -0400 Date: Thu, 20 Oct 2011 13:50:22 -0400 From: Vivek Goyal To: Kay Sievers Cc: Tejun Heo , axboe@kernel.dk, linux-kernel@vger.kernel.org, ctalbott@google.com, rni@google.com, containers@lists.linux-foundation.org Subject: Re: [PATCH 02/10] block: fix genhd refcounting in blkio_policy_parse_and_set() Message-ID: <20111020175022.GD13685@redhat.com> References: <1318998384-22525-3-git-send-email-tj@kernel.org> <20111019132657.GA1140@redhat.com> <20111019162902.GA25124@google.com> <20111019165932.GH1140@redhat.com> <20111019220553.GQ25124@google.com> <20111019220717.GR25124@google.com> <20111019235146.GS25124@google.com> <20111020134137.GA13685@redhat.com> <20111020161123.GW25124@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit 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 On Thu, Oct 20, 2011 at 06:16:04PM +0200, Kay Sievers wrote: > On Thu, Oct 20, 2011 at 18:11, Tejun Heo wrote: > > I think this is essentially a bug.  If you have something like "dev = > > find_and_get(); put(dev); return dev != NULL;", it's a pretty good > > indication something is pretty screwed there, so unless someone > > screams really loud, I think I'm gonna push for removal of the > > feature. > > Matching on unpredictable dev_t inside the kernel or in userspace is a > serious bug. We can't do anything like that ever on a modern system, > these times are long over. > > Yes, please get rid of this misguided logic, nobody should get the > impression that this can ever work. Kay, So are you suggesting don't use device major/minor number for specifying the rules in cgroup or you are suggesting the same thing as Tejun that automatically get rid of rule when device goes away. If it is former, then what else one can use for specifying the rule. Thanks Vivek