From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 28FCF7D043 for ; Thu, 21 Jun 2018 08:22:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932844AbeFUIWS convert rfc822-to-8bit (ORCPT ); Thu, 21 Jun 2018 04:22:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54576 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932430AbeFUIWQ (ORCPT ); Thu, 21 Jun 2018 04:22:16 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id F0245C057F4E; Thu, 21 Jun 2018 08:22:15 +0000 (UTC) Received: from llong.remote.csb (ovpn-116-35.phx2.redhat.com [10.3.116.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6563E5C54A; Thu, 21 Jun 2018 08:22:07 +0000 (UTC) Subject: Re: [PATCH v10 3/9] cpuset: Simulate auto-off of sched.domain_root at cgroup removal 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 References: <1529295249-5207-1-git-send-email-longman@redhat.com> <1529295249-5207-4-git-send-email-longman@redhat.com> <20180620141144.GI2494@hirez.programming.kicks-ass.net> From: Waiman Long Organization: Red Hat Message-ID: <6fffa761-a4ab-9974-c6b7-8c2af9d8a875@redhat.com> Date: Thu, 21 Jun 2018 16:22:05 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <20180620141144.GI2494@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Thu, 21 Jun 2018 08:22:16 +0000 (UTC) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 06/20/2018 10:11 PM, Peter Zijlstra wrote: > On Mon, Jun 18, 2018 at 12:14:02PM +0800, Waiman Long wrote: >> @@ -1058,7 +1060,12 @@ static int update_reserved_cpumask(struct cpuset *cpuset, >> * Check if any CPUs in addmask or delmask are in the effective_cpus >> * of a sibling cpuset. The implied cpu_exclusive of a scheduling >> * domain root will ensure there are no overlap in cpus_allowed. >> + * >> + * This check is skipped if the cpuset is dying. > Comments that state what the code does are mostly useless; please > explain _why_ if anything. I am adding more restrictions on where the domain_root can be turned on to make sure that there will be no surprise. I have a script to test the new cpuset v2 functionality and found that cgroup deletion may sometime failed if there was not enough time for the previous operation to complete. That is the reason why I relax the checking for dying cgroup to make my test script pass. Cheers, Longman -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html