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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 CA19CC468C6 for ; Thu, 19 Jul 2018 14:05:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8BA6120673 for ; Thu, 19 Jul 2018 14:05:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8BA6120673 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com 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 S1731789AbeGSOsS convert rfc822-to-8bit (ORCPT ); Thu, 19 Jul 2018 10:48:18 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:58756 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731497AbeGSOsS (ORCPT ); Thu, 19 Jul 2018 10:48:18 -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 3E64987AAB; Thu, 19 Jul 2018 14:04:57 +0000 (UTC) Received: from llong.remote.csb (dhcp-17-175.bos.redhat.com [10.18.17.175]) by smtp.corp.redhat.com (Postfix) with ESMTP id B2AC41C700; Thu, 19 Jul 2018 14:04:54 +0000 (UTC) Subject: Re: [PATCH v11 7/9] cpuset: Expose cpus.effective and mems.effective on cgroup v2 root To: Peter Zijlstra , Tejun Heo Cc: 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 References: <1529825440-9574-1-git-send-email-longman@redhat.com> <1529825440-9574-8-git-send-email-longman@redhat.com> <20180702165322.GI533219@devbig577.frc2.facebook.com> <20180703155823.GS533219@devbig577.frc2.facebook.com> <20180719135224.GE2494@hirez.programming.kicks-ass.net> From: Waiman Long Organization: Red Hat Message-ID: <1107494a-9667-df58-dcac-9366e969dc3a@redhat.com> Date: Thu, 19 Jul 2018 10:04:54 -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: <20180719135224.GE2494@hirez.programming.kicks-ass.net> 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 [10.11.55.1]); Thu, 19 Jul 2018 14:04:57 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Thu, 19 Jul 2018 14:04:57 +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-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/19/2018 09:52 AM, Peter Zijlstra wrote: > On Tue, Jul 03, 2018 at 08:58:23AM -0700, Tejun Heo wrote: >> Hello, Waiman. >> >> On Tue, Jul 03, 2018 at 08:41:31AM +0800, Waiman Long wrote: >>>> So, effective changing when enabling partition on a child feels wrong >>>> to me. It's supposed to contain what's actually allowed to the cgroup >>>> from its parent and that shouldn't change regardless of how those >>>> resources are used. It's still given to the cgroup from its parent. >>> Another way to work around this issue is to expose the reserved_cpus in >>> the parent for holding CPUs that can taken by a chid partition. That >>> will require adding one more cpuset file for those cgroups that are >>> partition roots. >> Yeah, that should work. >> >>> I don't mind restricting that to the first level children for now. That >>> does restrict where we can put the container root if we want a separate >>> partition for a container. Let's hear if others have any objection about >>> that. >> As currently implemented, partioning locks away the cpus which should >> be a system level decision, not container level, so it makes sense to >> me that it is only available to system root. > I'm terribly confused, what?! > > Why would a container not be allowed to create partitions for its > various RT workloads? As far as I understand, Tejun has some concern about the way that partitioning works is inconsistent with how other resources are being managed by cgroup v2 controllers. I adds an incremental patch to temporarily disable the creation of partition below the first level children to buy us time so that we can reach a compromise later on what to do. We can always add features, but taking away features after they are made available will be hard. I am fine either way. It is up to you and Tejun to figure out what should be made available to the users. Cheers, Longman