On Mon, 26 Sep 2016, Peter Zijlstra wrote:
> Currently dl tasks will actually return at the very beginning
> of rt_mutex_adjust_prio_chain() in !detect_deadlock cases:
>
> if (waiter->prio == task->prio) {
> if (!detect_deadlock)
> goto out_unlock_pi; // out here
> else
> requeue = false;
> }
>
> As the deadline value of blocked deadline tasks(waiters) without
> changing their sched_class(thus prio doesn't change) never changes,
> this seems reasonable, but it actually misses the chance of updating
> rt_mutex_waiter's "dl_runtime(period)_copy" if a waiter updates its
> deadline parameters(dl_runtime, dl_period) or boosted waiter changes
> to !deadline class.
>
> Thus, force deadline task not out by adding the !dl_prio() condition.
Reviewed-by: Thomas Gleixner <t...@linutronix.de>
