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sched/deadline/rtmutex: Dont miss the dl_runtime/dl_period update 

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.

Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: juri.lelli@arm.com
Cc: bigeasy@linutronix.de
Cc: mathieu.desnoyers@efficios.com
Cc: jdesfossez@efficios.com
Cc: bristot@redhat.com
Link: http://lkml.kernel.org/r/1460633827-345-7-git-send-email-xlpang@redhat.com
Link: http://lkml.kernel.org/r/20170323150216.206577901@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Xunlei Pang 2017-03-23 15:56:09 +01:00 committed by Thomas Gleixner
parent e96a7705e7
commit 85e2d4f992
1 changed files with 1 additions and 1 deletions
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2
kernel/locking/rtmutex.c
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@ -605,7 +605,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
* enabled we continue, but stop the requeueing in the chain
* walk.
*/
if (waiter->prio == task->prio) {
if (waiter->prio == task->prio && !dl_task(task)) {
if (!detect_deadlock)
goto out_unlock_pi;
else