From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zefan Li Subject: Re: [PATCH] cpuset: Enforce that a child's cpus must be a subset of the parent Date: Thu, 31 May 2018 09:25:29 +0800 Message-ID: <5B0F4F09.9050100@huawei.com> References: <1527687991-1431-1-git-send-email-longman@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1527687991-1431-1-git-send-email-longman@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Waiman Long , Tejun Heo , Johannes Weiner , Peter Zijlstra , Ingo Molnar Cc: 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 Hi Waiman, On 2018/5/30 21:46, Waiman Long wrote: > It was found that the cpuset.cpus could contain CPUs that are not listed > in their parent's cpu list as shown by the command sequence below: > > # echo "+cpuset" >cgroup.subtree_control > # mkdir g1 > # echo 0-5 >g1/cpuset.cpus > # mkdir g1/g11 > # echo "+cpuset" > g1/cgroup.subtree_control > # echo 6-11 >g1/g11/cpuset.cpus > # grep -R . g1 | grep "\.cpus" > g1/cpuset.cpus:0-5 > g1/cpuset.cpus.effective:0-5 > g1/g11/cpuset.cpus:6-11 > g1/g11/cpuset.cpus.effective:0-5 > > As the intersection of g11's cpus and that of g1 is empty, the effective > cpus of g11 is just that of g1. The check in update_cpumask() is now > corrected to make sure that cpus in a child cpus must be a subset of > its parent's cpus. The error "write error: Invalid argument" will now > be reported in the above case. > We made the distinction between user-configured CPUs and effective CPUs in commit 7e88291beefbb758, so actually it's not a bug. 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 3773F7D048 for ; Thu, 31 May 2018 01:26:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932593AbeEaB0B (ORCPT ); Wed, 30 May 2018 21:26:01 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:37168 "EHLO huawei.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S932563AbeEaB0A (ORCPT ); Wed, 30 May 2018 21:26:00 -0400 Received: from DGGEMS412-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 65231DBD8DDD9; Thu, 31 May 2018 09:25:56 +0800 (CST) Received: from [10.177.19.236] (10.177.19.236) by smtp.huawei.com (10.3.19.212) with Microsoft SMTP Server (TLS) id 14.3.382.0; Thu, 31 May 2018 09:25:55 +0800 Subject: Re: [PATCH] cpuset: Enforce that a child's cpus must be a subset of the parent To: Waiman Long , Tejun Heo , "Johannes Weiner" , Peter Zijlstra , "Ingo Molnar" References: <1527687991-1431-1-git-send-email-longman@redhat.com> CC: , , , , , , Mike Galbraith , , Roman Gushchin , Juri Lelli , Patrick Bellasi From: Zefan Li X-Enigmail-Draft-Status: N1110 Message-ID: <5B0F4F09.9050100@huawei.com> Date: Thu, 31 May 2018 09:25:29 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <1527687991-1431-1-git-send-email-longman@redhat.com> Content-Type: text/plain; charset="gbk" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.19.236] X-CFilter-Loop: Reflected Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Hi Waiman, On 2018/5/30 21:46, Waiman Long wrote: > It was found that the cpuset.cpus could contain CPUs that are not listed > in their parent's cpu list as shown by the command sequence below: > > # echo "+cpuset" >cgroup.subtree_control > # mkdir g1 > # echo 0-5 >g1/cpuset.cpus > # mkdir g1/g11 > # echo "+cpuset" > g1/cgroup.subtree_control > # echo 6-11 >g1/g11/cpuset.cpus > # grep -R . g1 | grep "\.cpus" > g1/cpuset.cpus:0-5 > g1/cpuset.cpus.effective:0-5 > g1/g11/cpuset.cpus:6-11 > g1/g11/cpuset.cpus.effective:0-5 > > As the intersection of g11's cpus and that of g1 is empty, the effective > cpus of g11 is just that of g1. The check in update_cpumask() is now > corrected to make sure that cpus in a child cpus must be a subset of > its parent's cpus. The error "write error: Invalid argument" will now > be reported in the above case. > We made the distinction between user-configured CPUs and effective CPUs in commit 7e88291beefbb758, so actually it's not a bug. -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932663AbeEaB0C (ORCPT ); Wed, 30 May 2018 21:26:02 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:37168 "EHLO huawei.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S932563AbeEaB0A (ORCPT ); Wed, 30 May 2018 21:26:00 -0400 Subject: Re: [PATCH] cpuset: Enforce that a child's cpus must be a subset of the parent To: Waiman Long , Tejun Heo , "Johannes Weiner" , Peter Zijlstra , "Ingo Molnar" References: <1527687991-1431-1-git-send-email-longman@redhat.com> CC: , , , , , , Mike Galbraith , , Roman Gushchin , Juri Lelli , Patrick Bellasi From: Zefan Li X-Enigmail-Draft-Status: N1110 Message-ID: <5B0F4F09.9050100@huawei.com> Date: Thu, 31 May 2018 09:25:29 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <1527687991-1431-1-git-send-email-longman@redhat.com> Content-Type: text/plain; charset="gbk" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.19.236] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Waiman, On 2018/5/30 21:46, Waiman Long wrote: > It was found that the cpuset.cpus could contain CPUs that are not listed > in their parent's cpu list as shown by the command sequence below: > > # echo "+cpuset" >cgroup.subtree_control > # mkdir g1 > # echo 0-5 >g1/cpuset.cpus > # mkdir g1/g11 > # echo "+cpuset" > g1/cgroup.subtree_control > # echo 6-11 >g1/g11/cpuset.cpus > # grep -R . g1 | grep "\.cpus" > g1/cpuset.cpus:0-5 > g1/cpuset.cpus.effective:0-5 > g1/g11/cpuset.cpus:6-11 > g1/g11/cpuset.cpus.effective:0-5 > > As the intersection of g11's cpus and that of g1 is empty, the effective > cpus of g11 is just that of g1. The check in update_cpumask() is now > corrected to make sure that cpus in a child cpus must be a subset of > its parent's cpus. The error "write error: Invalid argument" will now > be reported in the above case. > We made the distinction between user-configured CPUs and effective CPUs in commit 7e88291beefbb758, so actually it's not a bug.