From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S932749AbeCIWRt (ORCPT <rfc822;w@1wt.eu>);
        Fri, 9 Mar 2018 17:17:49 -0500
Received: from bombadil.infradead.org ([198.137.202.133]:59862 "EHLO
        bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S932104AbeCIWRs (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Fri, 9 Mar 2018 17:17:48 -0500
Date: Fri, 9 Mar 2018 23:17:36 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <longman@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>, Tejun Heo <tj@kernel.org>,
        Li Zefan <lizefan@huawei.com>, Johannes Weiner <hannes@cmpxchg.org>,
        Ingo Molnar <mingo@redhat.com>, cgroups@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
        kernel-team@fb.com, pjt@google.com, luto@amacapital.net,
        torvalds@linux-foundation.org, Roman Gushchin <guro@fb.com>
Subject: Re: [PATCH v4] cpuset: Enable cpuset controller in default hierarchy
Message-ID: <20180309221736.GB5926@hirez.programming.kicks-ass.net>
References: <1520609707-16582-1-git-send-email-longman@redhat.com>
 <1520613285.12489.36.camel@gmx.de>
 <1c3fe7b0-2600-c46d-1527-d3aaf024bb91@redhat.com>
 <1520619426.27998.18.camel@gmx.de>
 <55809fe4-98ba-5566-86ed-457acfef0e1c@redhat.com>
 <1520624424.27998.76.camel@gmx.de>
 <53de9683-01b7-bac4-8b70-dc1f93ede600@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <53de9683-01b7-bac4-8b70-dc1f93ede600@redhat.com>
User-Agent: Mutt/1.9.3 (2018-01-21)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Fri, Mar 09, 2018 at 03:43:34PM -0500, Waiman Long wrote:
> The isolcpus= parameter just reduce the cpus available to the rests of
> the system. The cpuset controller does look at that value and make
> adjustment accordingly, but it has no dependence on exclusive cpu/mem
> features of cpuset.

The isolcpus= boot param is donkey shit and needs to die. cpuset _used_
to be able to fully replace it, but with the advent of cgroup 'feature'
this got lost.

And instead of fixing it, you're making it _far_ worse. You completely
removed all the bits that allow repartitioning the scheduler domains.

Mike is completely right, full NAK on any such approach.