From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756034AbbCRQNl (ORCPT ); Wed, 18 Mar 2015 12:13:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44046 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754563AbbCRQNj (ORCPT ); Wed, 18 Mar 2015 12:13:39 -0400 Message-ID: <5509A430.9040005@redhat.com> Date: Wed, 18 Mar 2015 12:13:36 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: tj@kernel.org CC: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, lizefan@huawei.com Subject: Re: [PATCH v4 RESEND 0/4] cpusets,isolcpus: exclude isolcpus from load balancing in cpusets References: <1425917530-1771-1-git-send-email-riel@redhat.com> In-Reply-To: <1425917530-1771-1-git-send-email-riel@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/09/2015 12:12 PM, riel@redhat.com wrote: > Ensure that cpus specified with the isolcpus= boot commandline > option stay outside of the load balancing in the kernel scheduler. > > Operations like load balancing can introduce unwanted latencies, > which is exactly what the isolcpus= commandline is there to prevent. > > Previously, simply creating a new cpuset, without even touching the > cpuset.cpus field inside the new cpuset, would undo the effects of > isolcpus=, by creating a scheduler domain spanning the whole system, > and setting up load balancing inside that domain. The cpuset root > cpuset.cpus file is read-only, so there was not even a way to undo > that effect. > > This does not impact the majority of cpusets users, since isolcpus= > is a fairly specialized feature used for realtime purposes. > > This version fixes the UP compilation issue, in the same way done > for the other cpumasks. Ping? Tejun? Li?