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Date: Fri, 18 Nov 2016 16:47:48 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Luca Abeni <luca.abeni@unitn.it>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
        Juri Lelli <juri.lelli@arm.com>,
        Claudio Scordino <claudio@evidence.eu.com>,
        Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [RFC v3 2/6] Improve the tracking of active utilisation
Message-ID: <20161118154748.GN3142@twins.programming.kicks-ass.net>
References: <1477317998-7487-1-git-send-email-luca.abeni@unitn.it>
 <1477317998-7487-3-git-send-email-luca.abeni@unitn.it>
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On Mon, Oct 24, 2016 at 04:06:34PM +0200, Luca Abeni wrote:
> @@ -1074,6 +1161,14 @@ select_task_rq_dl(struct task_struct *p, int cpu, int sd_flag, int flags)
>  	}
>  	rcu_read_unlock();
>  
> +	rq = task_rq(p);
> +	raw_spin_lock(&rq->lock);
> +	if (hrtimer_active(&p->dl.inactive_timer)) {
> +		sub_running_bw(&p->dl, &rq->dl);
> +		hrtimer_try_to_cancel(&p->dl.inactive_timer);
> +	}
> +	raw_spin_unlock(&rq->lock);

Its a bit sad having to take rq->lock here...

Also, what happens when hrtimer_try_to_cancel() fails?

> +
>  out:
>  	return cpu;
>  }