From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751679AbdGRRzC (ORCPT ); Tue, 18 Jul 2017 13:55:02 -0400 Received: from mail-qt0-f195.google.com ([209.85.216.195]:33656 "EHLO mail-qt0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751408AbdGRRzA (ORCPT ); Tue, 18 Jul 2017 13:55:00 -0400 Date: Tue, 18 Jul 2017 13:54:56 -0400 From: Tejun Heo To: Peter Zijlstra Cc: lizefan@huawei.com, hannes@cmpxchg.org, mingo@redhat.com, longman@redhat.com, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, pjt@google.com, luto@amacapital.net, efault@gmx.de, torvalds@linux-foundation.org, guro@fb.com Subject: Re: [PATCH 5/6] cgroup: implement cgroup v2 thread support Message-ID: <20170718175456.GH585283@devbig577.frc2.facebook.com> References: <20170717020721.3612468-1-tj@kernel.org> <20170717020721.3612468-6-tj@kernel.org> <20170717141409.sqafufjupsiffnri@hirez.programming.kicks-ass.net> <20170717142609.GC3519177@devbig577.frc2.facebook.com> <20170718172801.f56273tzgzn3xkne@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170718172801.f56273tzgzn3xkne@hirez.programming.kicks-ass.net> 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 Hello, Peter. On Tue, Jul 18, 2017 at 07:28:01PM +0200, Peter Zijlstra wrote: > > And now try to create another child C, should that be a domain or > > threaded? > > Domain of course, as R must be a domain, and hence all its children > start out as such. I don't think it's a matter of course as R also is the root of a threaded subtree, but this is more or less bikeshedding. > > If we only inherit from the second level on, which is in itself > > already confusing, that still leads to invalid configs for non-root > > thread roots. > > I don't see how. I don't get the example Waiman gave, what is wrong > with: > > R (D) > | > A (D) > / \ > C(D) B(T) > > ? Afaict that's a perfectly valid configuration. Okay, we're kinda off the rails now. Just to verify that we're on the same page, are you also saying that the following should be a valid configuration? R (D) | A (D and has processes in it and controllers enabled) | C (D and has processes in it) Thanks. -- tejun