From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zefan Li Subject: Re: [PATCH 3/4] cpusets,isolcpus: add file to show isolated cpus in cpuset Date: Thu, 19 Mar 2015 09:50:04 +0800 Message-ID: <550A2B4C.5030705@huawei.com> References: <1425917530-1771-1-git-send-email-riel@redhat.com> <1425917530-1771-4-git-send-email-riel@redhat.com> <20150318164745.GA21564@htj.duckdns.org> <550A0CDF.1060709@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <550A0CDF.1060709@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Rik van Riel Cc: Tejun Heo , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Peter Zijlstra , Clark Williams , Ingo Molnar , Luiz Capitulino , David Rientjes , Mike Galbraith On 2015/3/19 7:40, Rik van Riel wrote: > On 03/18/2015 12:47 PM, Tejun Heo wrote: >> On Mon, Mar 09, 2015 at 12:12:09PM -0400, riel@redhat.com wrote: >>> From: Rik van Riel >>> >>> The previous patch makes it so the code skips over isolcpus when >>> building scheduler load balancing domains. This makes it hard to >>> see for a user which of the CPUs in a cpuset are participating in >>> load balancing, and which ones are isolated cpus. >>> >>> Add a cpuset.isolcpus file with info on which cpus in a cpuset are >>> isolated CPUs. >>> >>> This file is read-only for now. In the future we could extend things >>> so isolcpus can be changed at run time, for the root (system wide) >>> cpuset only. >> >> Didn't Li say that this is trivially computable from userland? I'm >> not sure this knob actually belongs to cpuset. > > I don't know whether the information to compute this is > always visible from userland. I am happy to drop this > patch if Li prefers things that way, though. > What I proposed is adding /sys/devices/system/cpu/isolated. Sysfs is visible in containers, unless specially configured not so. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754835AbbCSBzH (ORCPT ); Wed, 18 Mar 2015 21:55:07 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:2296 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752838AbbCSBzA (ORCPT ); Wed, 18 Mar 2015 21:55:00 -0400 Message-ID: <550A2B4C.5030705@huawei.com> Date: Thu, 19 Mar 2015 09:50:04 +0800 From: Zefan Li User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: Rik van Riel CC: Tejun Heo , , , Peter Zijlstra , "Clark Williams" , Ingo Molnar , "Luiz Capitulino" , David Rientjes , Mike Galbraith Subject: Re: [PATCH 3/4] cpusets,isolcpus: add file to show isolated cpus in cpuset References: <1425917530-1771-1-git-send-email-riel@redhat.com> <1425917530-1771-4-git-send-email-riel@redhat.com> <20150318164745.GA21564@htj.duckdns.org> <550A0CDF.1060709@redhat.com> In-Reply-To: <550A0CDF.1060709@redhat.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.18.230] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020202.550A2B98.0030,ss=1,re=0.001,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: b9671c569e682b7aa2d2cfd0bf16a4af Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/3/19 7:40, Rik van Riel wrote: > On 03/18/2015 12:47 PM, Tejun Heo wrote: >> On Mon, Mar 09, 2015 at 12:12:09PM -0400, riel@redhat.com wrote: >>> From: Rik van Riel >>> >>> The previous patch makes it so the code skips over isolcpus when >>> building scheduler load balancing domains. This makes it hard to >>> see for a user which of the CPUs in a cpuset are participating in >>> load balancing, and which ones are isolated cpus. >>> >>> Add a cpuset.isolcpus file with info on which cpus in a cpuset are >>> isolated CPUs. >>> >>> This file is read-only for now. In the future we could extend things >>> so isolcpus can be changed at run time, for the root (system wide) >>> cpuset only. >> >> Didn't Li say that this is trivially computable from userland? I'm >> not sure this knob actually belongs to cpuset. > > I don't know whether the information to compute this is > always visible from userland. I am happy to drop this > patch if Li prefers things that way, though. > What I proposed is adding /sys/devices/system/cpu/isolated. Sysfs is visible in containers, unless specially configured not so.