From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zefan Li Subject: Re: [PATCH] sched: Relax a restriction in sched_rt_can_attach() Date: Tue, 5 May 2015 11:46:00 +0800 Message-ID: <55483CF8.8030908@huawei.com> References: <5546C34C.7050202@huawei.com> <1430709236.3129.42.camel@gmail.com> <5546F80B.3070802@huawei.com> <1430716247.3129.44.camel@gmail.com> <1430717964.3129.62.camel@gmail.com> <554737AE.5040402@huawei.com> <20150504123738.GZ21418@twins.programming.kicks-ass.net> <1430748582.3166.16.camel@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1430748582.3166.16.camel-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Mike Galbraith Cc: Peter Zijlstra , Ingo Molnar , Tejun Heo , LKML , Cgroups On 2015/5/4 22:09, Mike Galbraith wrote: > On Mon, 2015-05-04 at 14:37 +0200, Peter Zijlstra wrote: >> On Mon, May 04, 2015 at 05:11:10PM +0800, Zefan Li wrote: >> >>> Some degree of flexibility is provided so that you may disable some controllers >>> in a subtree. For example: >>> >>> root ---> child1 >>> (cpuset,memory,cpu) (cpuset,memory) >>> \ >>> \-> child2 >>> (cpu) >> >> Uhm, how does that work? Would a task their effective cgroup be the >> first parent that has a controller enabled? >> >> In particular, in your example, if T were part of child1, would its cpu >> controller be root? correct. > > That's what I'd hope for. I wanted to try that cgroup.subtree_control > gizmo to see for myself, but I don't have one, and probably won't get > one until I introduce systemd to my axe (again, it's a slow learner). > I'm testing in an environment without systemd. You need to mount cgroup with a special option: # mount -t cgroup -o __DEVEL__sane_behavior xxx /where If a cgroup controller has already been mounted without this option, you won't see it in the unified hierarchy, so firstly you need to delete all cgroups in it and umount it. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755521AbbEEDrQ (ORCPT ); Mon, 4 May 2015 23:47:16 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:5828 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755497AbbEEDrG (ORCPT ); Mon, 4 May 2015 23:47:06 -0400 Message-ID: <55483CF8.8030908@huawei.com> Date: Tue, 5 May 2015 11:46:00 +0800 From: Zefan Li User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: Mike Galbraith CC: Peter Zijlstra , Ingo Molnar , Tejun Heo , LKML , Cgroups Subject: Re: [PATCH] sched: Relax a restriction in sched_rt_can_attach() References: <5546C34C.7050202@huawei.com> <1430709236.3129.42.camel@gmail.com> <5546F80B.3070802@huawei.com> <1430716247.3129.44.camel@gmail.com> <1430717964.3129.62.camel@gmail.com> <554737AE.5040402@huawei.com> <20150504123738.GZ21418@twins.programming.kicks-ass.net> <1430748582.3166.16.camel@gmail.com> In-Reply-To: <1430748582.3166.16.camel@gmail.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.18.230] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/5/4 22:09, Mike Galbraith wrote: > On Mon, 2015-05-04 at 14:37 +0200, Peter Zijlstra wrote: >> On Mon, May 04, 2015 at 05:11:10PM +0800, Zefan Li wrote: >> >>> Some degree of flexibility is provided so that you may disable some controllers >>> in a subtree. For example: >>> >>> root ---> child1 >>> (cpuset,memory,cpu) (cpuset,memory) >>> \ >>> \-> child2 >>> (cpu) >> >> Uhm, how does that work? Would a task their effective cgroup be the >> first parent that has a controller enabled? >> >> In particular, in your example, if T were part of child1, would its cpu >> controller be root? correct. > > That's what I'd hope for. I wanted to try that cgroup.subtree_control > gizmo to see for myself, but I don't have one, and probably won't get > one until I introduce systemd to my axe (again, it's a slow learner). > I'm testing in an environment without systemd. You need to mount cgroup with a special option: # mount -t cgroup -o __DEVEL__sane_behavior xxx /where If a cgroup controller has already been mounted without this option, you won't see it in the unified hierarchy, so firstly you need to delete all cgroups in it and umount it.