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authorThomas Gleixner <tglx@linutronix.de>2014-02-07 20:58:42 +0100
committerIngo Molnar <mingo@kernel.org>2014-02-22 18:10:04 +0100
commitc365c292d05908c6ea6f32708f331e21033fe71d (patch)
treefcaf27f6d0296ef48203f940d1ed9d8c02c56860 /kernel/locking
parent81a44c5441d7f7d2c3dc9105f4d65ad0d5818617 (diff)
downloadop-kernel-dev-c365c292d05908c6ea6f32708f331e21033fe71d.zip
op-kernel-dev-c365c292d05908c6ea6f32708f331e21033fe71d.tar.gz
sched: Consider pi boosting in setscheduler()
If a PI boosted task policy/priority is modified by a setscheduler() call we unconditionally dequeue and requeue the task if it is on the runqueue even if the new priority is lower than the current effective boosted priority. This can result in undesired reordering of the priority bucket list. If the new priority is less or equal than the current effective we just store the new parameters in the task struct and leave the scheduler class and the runqueue untouched. This is handled when the task deboosts itself. Only if the new priority is higher than the effective boosted priority we apply the change immediately. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [ Rebase ontop of v3.14-rc1. ] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Dario Faggioli <raistlin@linux.it> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1391803122-4425-7-git-send-email-bigeasy@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/rtmutex.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 2e960a2..aa4dff0 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -213,6 +213,18 @@ struct task_struct *rt_mutex_get_top_task(struct task_struct *task)
}
/*
+ * Called by sched_setscheduler() to check whether the priority change
+ * is overruled by a possible priority boosting.
+ */
+int rt_mutex_check_prio(struct task_struct *task, int newprio)
+{
+ if (!task_has_pi_waiters(task))
+ return 0;
+
+ return task_top_pi_waiter(task)->task->prio <= newprio;
+}
+
+/*
* Adjust the priority of a task, after its pi_waiters got modified.
*
* This can be both boosting and unboosting. task->pi_lock must be held.
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