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 S935381AbeE2BNB (ORCPT <rfc822;w@1wt.eu>);
        Mon, 28 May 2018 21:13:01 -0400
Received: from mx3-rdu2.redhat.com ([66.187.233.73]:34588 "EHLO mx1.redhat.com"
        rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP
        id S935196AbeE2BM6 (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Mon, 28 May 2018 21:12:58 -0400
Subject: Re: [PATCH v8 4/6] cpuset: Make generate_sched_domains() recognize
 isolated_cpus
To: Juri Lelli <juri.lelli@redhat.com>
Cc: Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Peter Zijlstra <peterz@infradead.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, Mike Galbraith <efault@gmx.de>,
        torvalds@linux-foundation.org, Roman Gushchin <guro@fb.com>
References: <1526590545-3350-1-git-send-email-longman@redhat.com>
 <1526590545-3350-5-git-send-email-longman@redhat.com>
 <20180524102837.GA3948@localhost.localdomain>
From: Waiman Long <longman@redhat.com>
Organization: Red Hat
Message-ID: <45d70c88-e9f5-716a-ee9a-33dc111159cc@redhat.com>
Date: Mon, 28 May 2018 21:12:55 -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: <20180524102837.GA3948@localhost.localdomain>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Content-Language: en-US
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 05/24/2018 06:28 AM, Juri Lelli wrote:
> On 17/05/18 16:55, Waiman Long wrote:
>
> [...]
>
>> @@ -849,7 +860,12 @@ static void rebuild_sched_domains_locked(void)
>>  	 * passing doms with offlined cpu to partition_sched_domains().
>>  	 * Anyways, hotplug work item will rebuild sched domains.
>>  	 */
>> -	if (!cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
>> +	if (!top_cpuset.isolation_count &&
>> +	    !cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
>> +		goto out;
>> +
>> +	if (top_cpuset.isolation_count &&
>> +	   !cpumask_subset(top_cpuset.effective_cpus, cpu_active_mask))
>>  		goto out;
> Do we cover the case in which hotplug removed one of the isolated cpus
> from cpu_active_mask?

Yes, you are right. That is the remnant of my original patch that allows
only one isolated_cpus at root. Thanks for spotting that.

Cheers,
Longman