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.