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 DF758C468C6 for ; Thu, 19 Jul 2018 15:52:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9AE2D2084E for ; Thu, 19 Jul 2018 15:52:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9AE2D2084E 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 S1732033AbeGSQgj convert rfc822-to-8bit (ORCPT ); Thu, 19 Jul 2018 12:36:39 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:37208 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727575AbeGSQgj (ORCPT ); Thu, 19 Jul 2018 12:36:39 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AB84E407563F; Thu, 19 Jul 2018 15:52:50 +0000 (UTC) Received: from llong.remote.csb (ovpn-125-125.rdu2.redhat.com [10.10.125.125]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0917D2156897; Thu, 19 Jul 2018 15:52:46 +0000 (UTC) Subject: Re: [PATCH v11 7/9] cpuset: Expose cpus.effective and mems.effective on cgroup v2 root To: Tejun Heo Cc: Peter Zijlstra , 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> <1107494a-9667-df58-dcac-9366e969dc3a@redhat.com> <20180719153045.GT72677@devbig577.frc2.facebook.com> From: Waiman Long Organization: Red Hat Message-ID: Date: Thu, 19 Jul 2018 11:52:46 -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: <20180719153045.GT72677@devbig577.frc2.facebook.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Content-Language: en-US X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Thu, 19 Jul 2018 15:52:50 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Thu, 19 Jul 2018 15:52:50 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.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 11:30 AM, Tejun Heo wrote: > Hello, > > On Thu, Jul 19, 2018 at 10:04:54AM -0400, Waiman Long wrote: >>> 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. > So, the main thing is that putting a cpu into a partition locks away > the cpu from its ancestors. That's a system level operation which > isn't delegatable. If we want to allow partitioning in subtrees, the > parent still be able to take away partitioned cpus too even if that > means ignoring descendants' configurations, which btw is exactly what > cpuset does for non-partition configs. > > I don't think this would be technically too challenging to implement, > but unless there are immediate use cases for it, we can start simpler > & restricted. > > Thanks. > BTW, the way the partition is currently implemented right now is that a child cannot be a partition root unless its parent is a partition root itself. That is to avoid turning on partition to affect ancestors further up the hierarchy than just the parent. So in the case of a container, it cannot allocate sub-partitions underneath it unless it is a partition itself. Will that solve your concern? Thanks, Longman