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Date: Wed, 25 Oct 2017 11:30:41 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Prateek Sood <prsood@codeaurora.org>
Cc: tj@kernel.org, lizefan@huawei.com, cgroups@vger.kernel.org,
        mingo@kernel.org, longman@redhat.com, boqun.feng@gmail.com,
        tglx@linutronix.de, linux-kernel@vger.kernel.org,
        sramana@codeaurora.org
Subject: Re: [PATCH] cgroup/cpuset: remove circular dependency deadlock
Message-ID: <20171025093041.GO3165@worktop.lehotels.local>
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On Wed, Oct 25, 2017 at 02:09:54PM +0530, Prateek Sood wrote:
> >  void cpuset_update_active_cpus(void)
> >  {
> > +	mutex_lock(&cpuset_mutex);
> > +	rebuild_sched_domains_cpuslocked();
> > +	mutex_unlock(&cpuset_mutex);
> >  }
> 
> In the above patch rebuild_sched_domains_cpuslocked() has been
> used directly. Earlier cpuset_hotplug_update_tasks() was also
> called from cpuset_hotplug_workfn(). So migration of tasks
> related to cgroup which has empty cpuset would not happen
> during cpu hotplug.
> 
> 
> Could you please help in understanding more on this.
> 

That was me being lazy...