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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7BCBDCCA47D for ; Mon, 13 Jun 2022 19:10:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235346AbiFMTKt (ORCPT ); Mon, 13 Jun 2022 15:10:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349365AbiFMTIr (ORCPT ); Mon, 13 Jun 2022 15:08:47 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 33EE950061 for ; Mon, 13 Jun 2022 10:06:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1655139987; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=s7hhCYT7OGqCx5nH+qXS1ao3TYt75AzmKiJLPQv1MlY=; b=dN7XFuXy/NWHD2GALDrP/g+Tp4sT4W9Tv4HMrVJG6rUUtnNYuOkLd70ou+1H4i9IIEphie A8kaF705rtufmt6MmOPibuYCLTEA1qQj4oT3ThVchBnKt3CZo2DGW5qjvf9eX7Vd2uCnmH 07Yxv6ZGdibYBrILf0/Rv5c+kgGsTMc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-29-u9ZkP3_qMFWE3PS8XzGi6A-1; Mon, 13 Jun 2022 13:06:22 -0400 X-MC-Unique: u9ZkP3_qMFWE3PS8XzGi6A-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3825D801756; Mon, 13 Jun 2022 17:06:21 +0000 (UTC) Received: from [10.18.17.215] (dhcp-17-215.bos.redhat.com [10.18.17.215]) by smtp.corp.redhat.com (Postfix) with ESMTP id 68A6F2026D64; Mon, 13 Jun 2022 17:06:20 +0000 (UTC) Message-ID: Date: Mon, 13 Jun 2022 13:06:20 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH v11 7/8] cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst Content-Language: en-US From: Waiman Long To: Tejun Heo Cc: Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton , Roman Gushchin , Phil Auld , Peter Zijlstra , Juri Lelli , Frederic Weisbecker , Marcelo Tosatti , =?UTF-8?Q?Michal_Koutn=c3=bd?= References: <20220510153413.400020-1-longman@redhat.com> <20220510153413.400020-8-longman@redhat.com> <404171dc-0da3-21f2-5003-9718f875e967@redhat.com> <8d7ddb5a-0d0b-3f2e-e049-900360e95fc6@redhat.com> In-Reply-To: <8d7ddb5a-0d0b-3f2e-e049-900360e95fc6@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On 6/13/22 09:18, Waiman Long wrote: > On 6/12/22 23:12, Tejun Heo wrote: >> Hello, >> >> On Sun, Jun 12, 2022 at 11:02:38PM -0400, Waiman Long wrote: >>> That is the behavior enforced by setting the CPU_EXCLUSIVE bit in >>> cgroup v1. >>> I haven't explicitly change it to make it different in cgroup v2. >>> The major >>> reason is that I don't want change to one cpuset to affect a sibling >>> partition as it may make the code more complicate to validate if a >>> partition >>> is valid. >> If at all possible, I'd really like to avoid situations where a >> parent can't >> withdraw resources due to something that a descendant does. > > No, it doesn't affect parent at all. It just limit whats the siblings > can do due to their mutual constraint. If this is what the confusion > is about, I will try to reword the doc text. I am planning to make the following change to the documentation patch. Please let me know if that can clarify the confusion, if any. Thanks, Longman diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guid> index 9184a09e0fc9..9cbfa25dab97 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -2176,7 +2175,8 @@ Cpuset Interface Files         For a valid partition root or an invalid partition root with         the exclusivity rule enabled, changes made to "cpuset.cpus" -       that violate the exclusivity rule will not be allowed. +       that violate the exclusivity rule with its siblings will not +       be allowed.         A valid non-root parent partition may distribute out all its CPUs         to its child partitions when there is no task associated with it.