From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 635DDC1B0F2 for ; Wed, 20 Jun 2018 14:12:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 07CF020872 for ; Wed, 20 Jun 2018 14:12:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="nkDEBr1v" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 07CF020872 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754002AbeFTOMC (ORCPT ); Wed, 20 Jun 2018 10:12:02 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:59604 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752827AbeFTOMA (ORCPT ); Wed, 20 Jun 2018 10:12:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=fszqOchqOK3zF6lfDyZsNt7DpBDbt1prSdKz0mQ/Vac=; b=nkDEBr1v+wQdIXBAbpPMewwXH ikym0EHbvTkNrpgGatILlOzNxqC+wGfnKDkFb4wHzyaPlqAa9xIz4J78Te/1OviOBCq9cI1D2GEhe /EGBiryv3/kSnaFw3rmlz3+Bt3Y4cR2CWnsxiApROVEyuXTM1G6SfS5U74vh2JDS0gYDyqHRv+rMb dofvYdyJCCySf/dkTUDDqHOZ94YzSHPT5xYLOBPwIRF2Vpf6heUKyM2Af3giTr42MXqgDjxmRuhds 7bT6v1NvJflu5WfF/AzGhqyuRgzphX7XZAUpa/voOKaMRSAPASzn6rDb3BhygM23vJXWpppjYALJy gpSoX7y+w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fVdpq-0000fS-FA; Wed, 20 Jun 2018 14:11:46 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 61DEA2029F1D5; Wed, 20 Jun 2018 16:11:44 +0200 (CEST) Date: Wed, 20 Jun 2018 16:11:44 +0200 From: Peter Zijlstra To: Waiman Long 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 Subject: Re: [PATCH v10 3/9] cpuset: Simulate auto-off of sched.domain_root at cgroup removal Message-ID: <20180620141144.GI2494@hirez.programming.kicks-ass.net> References: <1529295249-5207-1-git-send-email-longman@redhat.com> <1529295249-5207-4-git-send-email-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1529295249-5207-4-git-send-email-longman@redhat.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > */ > + if (dying) > + goto updated_reserved_cpus; > + > rcu_read_lock(); > cpuset_for_each_child(sibling, pos_css, parent) { > if ((sibling == cpuset) || !(sibling->css.flags & CSS_ONLINE))