From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753772Ab2LFE0r (ORCPT ); Wed, 5 Dec 2012 23:26:47 -0500 Received: from 50-56-35-84.static.cloud-ips.com ([50.56.35.84]:35157 "EHLO mail.hallyn.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753211Ab2LFE0p (ORCPT ); Wed, 5 Dec 2012 23:26:45 -0500 Date: Thu, 6 Dec 2012 04:31:30 +0000 From: "Serge E. Hallyn" To: Aristeu Rozanski Cc: "Serge E. Hallyn" , linux-kernel@vger.kernel.org, Tejun Heo , Serge Hallyn , cgroups@vger.kernel.org Subject: Re: [PATCH 3/5] device_cgroup: keep track of local group settings Message-ID: <20121206043130.GA22792@mail.hallyn.com> References: <20121127193501.255267751@napanee.usersys.redhat.com> <20121127193502.482004744@napanee.usersys.redhat.com> <20121129192945.GD26104@mail.hallyn.com> <20121129195942.GW32112@redhat.com> <20121129202608.GA26716@mail.hallyn.com> <20121129223111.GZ32112@redhat.com> <20121203180125.GA30637@mail.hallyn.com> <20121203190657.GD32112@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121203190657.GD32112@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 Quoting Aristeu Rozanski (aris@redhat.com): > On Mon, Dec 03, 2012 at 06:01:25PM +0000, Serge E. Hallyn wrote: > > First, generally, I don't think 'allows' added to parent should be > > automatically propagated to descendents. > > that's what I think too and what I tried to do > > > In devcgroup_update_access: (around line 625) > > there is a period of time where cgroup members have > > default allow without the parent's exceptions. > > true, will fix that one and look for more cases > > > propagate_behavior (line 505): > > 1. doesn't follow the same ordering as devcgroup_update_access(), in > > particular cleaning exceptions before setting behavior. > > I see, will update that > > > 2. When changing a parent from deny to allow, I don't think children > > should be updated. > > I disagree on this one. since there'll be local preferences, it'll try > to revalidate them everytime there's a change. so, for example, an > exception that might not be possible now, will be possible when its > parent changes in a way that allows that. My concern is just practical - if I've started a bunch of containers, and another admin decides to make a change to the root devices cgroup, I don't want the container's device accesses now changing. Maybe that's better solved by having all of userspace sit in /system while containers and vms sit under /lxc and /libvirt... -serge