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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 3EB5EC32789 for ; Tue, 6 Nov 2018 11:37:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 059EC206BA for ; Tue, 6 Nov 2018 11:37:33 +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="WPmdbnof" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 059EC206BA 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 S1730602AbeKFVCR (ORCPT ); Tue, 6 Nov 2018 16:02:17 -0500 Received: from merlin.infradead.org ([205.233.59.134]:57158 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730262AbeKFVCQ (ORCPT ); Tue, 6 Nov 2018 16:02:16 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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=nhV7MP9fmom1olzqQQOBdE69jYgH85uDi+QqRtqAtg8=; b=WPmdbnofwrpymTzT3W5uqbalC yXkbFo768UY/COShyd5oe5c/+DoDMcPiDFDEILxY+/wsrTsSwSUZ4F05ry8gNXXwaE5gHDPLs8QTC 8FOM6qPfvhqcAWFF4hlWMrzKVwo9XHGgxrVAVxG+ZumK+LJlNl3izMYnOdazqgP+8wfFSSQVOK+id 6eylgHIMpBHZgN8MdD3Avg4w7iz6BYU7Mi5gH8AH+esD0/JhIveGhdjryxAsGVHr9CcS/xdcFXBt2 +cRP7RsEAQh4WglbaXK9j++C8OZn1Lhy1XQldL9yfTI+TYrJ4ztw0+qI2LCjq1LVDeK76dBmdObhS jXOrHc29w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gJzfa-0005i1-Bz; Tue, 06 Nov 2018 11:37:18 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id D61242029F9FF; Tue, 6 Nov 2018 12:37:12 +0100 (CET) Date: Tue, 6 Nov 2018 12:37:12 +0100 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 , Tom Hromatka Subject: Re: [PATCH v14 05/12] cpuset: Add an error state to cpuset.sched.partition Message-ID: <20181106113712.GL22431@hirez.programming.kicks-ass.net> References: <1539635377-22335-1-git-send-email-longman@redhat.com> <1539635377-22335-6-git-send-email-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1539635377-22335-6-git-send-email-longman@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 15, 2018 at 04:29:30PM -0400, Waiman Long wrote: > Handling error returned by update_parent_subparts_cpumask() in > update_cpumasks_hier() is problematic as the states may become > inconsistent. To avoid that and increase flexibility in handling other > error cases, a new error state (-1) is added to the partition_root_state > flag. This new error state is set internally and user cannot write this > value to "cpuset.sched.partition". > > In this error state, the partition root becomes an erroneous one. It is > no longer a real partition root, but the CS_CPU_EXCLUSIVE flag will > still be set as it can be changed back to a real one if appropriate > change happens later on. I feel this Changelog should be much more explicit about the reasons this -1 state can happen. As is, I've got no clue.