From mboxrd@z Thu Jan 1 00:00:00 1970 From: Waiman Long Subject: Re: [PATCH v10 5/9] cpuset: Make sure that domain roots work properly with CPU hotplug Date: Thu, 21 Jun 2018 11:09:22 +0800 Message-ID: References: <1529295249-5207-1-git-send-email-longman@redhat.com> <1529295249-5207-6-git-send-email-longman@redhat.com> <20180620141538.GJ2494@hirez.programming.kicks-ass.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180620141538.GJ2494@hirez.programming.kicks-ass.net> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Peter Zijlstra Cc: Tejun Heo , Li Zefan , Johannes Weiner , Ingo Molnar , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kernel-team@fb.com, pjt@google.com, luto@amacapital.net, Mike Galbraith , torvalds@linux-foundation.org, Roman Gushchin , Juri Lelli , Patrick Bellasi On 06/20/2018 10:15 PM, Peter Zijlstra wrote: > On Mon, Jun 18, 2018 at 12:14:04PM +0800, Waiman Long wrote: >> diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst >> index 5ee5e77..6ef3516 100644 >> --- a/Documentation/admin-guide/cgroup-v2.rst >> +++ b/Documentation/admin-guide/cgroup-v2.rst >> @@ -1626,6 +1626,13 @@ Cpuset Interface Files >> 2) No CPU that has been distributed to child scheduling domain >> roots is deleted. >> >> + When all the CPUs allocated to a scheduling domain are offlined, >> + that scheduling domain will be temporaily gone and all the >> + tasks in that scheduling domain will migrate to another one that >> + belongs to the parent of the scheduling domain root. When any >> + of those offlined CPUs is onlined again, a new scheduling domain >> + will be re-created and the tasks will be migrated back. >> + > You should mention that this is a destructive operation. If any of the > tasks had an affinity smaller than the original cgroup, that will be > gone. Thanks for the information. Will update the documentation to mention that. Cheers, Longman