Commit-ID: 85e2d4f992868ad78dc8bb2c077b652fcfb3661a
Gitweb: http://git.kernel.org/tip/85e2d4f992868ad78dc8bb2c077b652fcfb3661a
Author: Xunlei Pang <xlpang@xxxxxxxxxx>
AuthorDate: Thu, 23 Mar 2017 15:56:09 +0100
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 4 Apr 2017 11:44:05 +0200
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@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: juri.lelli@xxxxxxx
Cc: bigeasy@xxxxxxxxxxxxx
Cc: mathieu.desnoyers@xxxxxxxxxxxx
Cc: jdesfossez@xxxxxxxxxxxx
Cc: bristot@xxxxxxxxxx
Link: http://lkml.kernel.org/r/1460633827-345-7-git-send-email-xlpang@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20170323150216.206577901@xxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
kernel/locking/rtmutex.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index bc05b10..8faf472 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -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
--
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