locking/rtmutex: Remove unnecessary priority adjustment
authorAlex Shi <alex.shi@linaro.org>
Thu, 13 Jul 2017 06:18:24 +0000 (14:18 +0800)
committerIngo Molnar <mingo@kernel.org>
Thu, 13 Jul 2017 09:44:06 +0000 (11:44 +0200)
We don't need to adjust priority before adding a new pi_waiter, the
priority only needs to be updated after pi_waiter change or task
priority change.

Steven Rostedt pointed out:

  "Interesting, I did some git mining and this was added with the original
   entry of the rtmutex.c (23f78d4a03c5). Looking at even that version, I
   don't see the purpose of adjusting the task prio here. It is done
   before anything changes in the task."

Signed-off-by: Alex Shi <alex.shi@linaro.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1499926704-28841-1-git-send-email-alex.shi@linaro.org
[ Enhance the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kernel/locking/rtmutex.c

index 7806989..649dc9d 100644 (file)
@@ -963,7 +963,6 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
                return -EDEADLK;
 
        raw_spin_lock(&task->pi_lock);
-       rt_mutex_adjust_prio(task);
        waiter->task = task;
        waiter->lock = lock;
        waiter->prio = task->prio;