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Date:   Thu, 24 May 2018 12:28:37 +0200
From:   Juri Lelli <juri.lelli@redhat.com>
To:     Waiman Long <longman@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>
Subject: Re: [PATCH v8 4/6] cpuset: Make generate_sched_domains() recognize
 isolated_cpus
Message-ID: <20180524102837.GA3948@localhost.localdomain>
References: <1526590545-3350-1-git-send-email-longman@redhat.com>
 <1526590545-3350-5-git-send-email-longman@redhat.com>
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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?