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=-4.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_HI,T_RP_MATCHES_RCVD 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 66D947DD31 for ; Tue, 27 Mar 2018 14:24:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752044AbeC0OXn convert rfc822-to-8bit (ORCPT ); Tue, 27 Mar 2018 10:23:43 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:53272 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751292AbeC0OXi (ORCPT ); Tue, 27 Mar 2018 10:23:38 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B9EA840201AC; Tue, 27 Mar 2018 14:23:36 +0000 (UTC) Received: from llong.remote.csb (dhcp-17-164.bos.redhat.com [10.18.17.164]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5BEC76F9E6; Tue, 27 Mar 2018 14:23:33 +0000 (UTC) Subject: Re: [PATCH v6 2/2] cpuset: Add cpuset.sched_load_balance to v2 To: Tejun Heo Cc: Juri Lelli , Li Zefan , Johannes Weiner , Peter Zijlstra , 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, efault@gmx.de, torvalds@linux-foundation.org, Roman Gushchin References: <1521649309-26690-1-git-send-email-longman@redhat.com> <1521649309-26690-3-git-send-email-longman@redhat.com> <20180322084120.GE7231@localhost.localdomain> <20180323075952.GA4763@localhost.localdomain> <20180326124711.GE5942@localhost.localdomain> <20180327140259.GN1840639@devbig577.frc2.facebook.com> From: Waiman Long Organization: Red Hat Message-ID: Date: Tue, 27 Mar 2018 10:23:33 -0400 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: <20180327140259.GN1840639@devbig577.frc2.facebook.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Tue, 27 Mar 2018 14:23:36 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Tue, 27 Mar 2018 14:23:36 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'longman@redhat.com' RCPT:'' Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 03/27/2018 10:02 AM, Tejun Heo wrote: > Hello, > > On Mon, Mar 26, 2018 at 04:28:49PM -0400, Waiman Long wrote: >> Maybe we can have a different root level flag, say, >> sched_partition_domain that is equivalent to !sched_load_balnace. >> However, I am still not sure if we should enforce that no task should be >> in the root cgroup when the flag is set. >> >> Tejun and Peter, what are your thoughts on this? > I haven't looked into the other issues too much but we for sure cannot > empty the root cgroup. > > Thanks. > Now, I have a different idea. How about we add a special root-only knob, say, "cpuset.cpus.isolated" that contains the list of CPUs that are still owned by root, but not participated in load balancing. All the tasks in the root are load-balanced among the remaining CPUs. A child can then be created that hold some or all the CPUs in the isolated set. It will then have a separate root domain if load balancing is on, or an isolated cpuset if load balancing is off. Will that idea work? 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