Merge "Add the "timers: do not raise softirq unconditionally" temporarily"

2 files changed, 29 insertions, 8 deletions

diff --git a/kernel/kernel/locking/rtmutex.c b/kernel/kernel/locking/rtmutex.c
index 66971005c..30777e813 100644
--- a/kernel/kernel/locking/rtmutex.c
+++ b/kernel/kernel/locking/rtmutex.c
@@ -2058,13 +2058,6 @@ EXPORT_SYMBOL_GPL(rt_mutex_timed_lock);
  */
 int __sched rt_mutex_trylock(struct rt_mutex *lock)
 {
-#ifdef CONFIG_PREEMPT_RT_FULL
-	if (WARN_ON(in_irq() || in_nmi()))
-#else
-	if (WARN_ON(in_irq() || in_nmi() || in_serving_softirq()))
-#endif
-		return 0;
-
 	return rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_trylock);
diff --git a/kernel/kernel/time/timer.c b/kernel/kernel/time/timer.c
index fee8682c2..76a301b24 100644
--- a/kernel/kernel/time/timer.c
+++ b/kernel/kernel/time/timer.c
@@ -1509,8 +1509,36 @@ static void run_timer_softirq(struct softirq_action *h)
  */
 void run_local_timers(void)
 {
+	struct tvec_base *base = this_cpu_ptr(&tvec_bases);
+
 	hrtimer_run_queues();
-	raise_softirq(TIMER_SOFTIRQ);
+	/*
+	 * We can access this lockless as we are in the timer
+	 * interrupt. If there are no timers queued, nothing to do in
+	 * the timer softirq.
+	 */
+#ifdef CONFIG_PREEMPT_RT_FULL
+	if (irq_work_needs_cpu()) {
+		raise_softirq(TIMER_SOFTIRQ);
+		return;
+	}
+	if (!spin_do_trylock(&base->lock)) {
+		raise_softirq(TIMER_SOFTIRQ);
+		return;
+	}
+#endif
+	if (!base->active_timers)
+		goto out;
+
+	/* Check whether the next pending timer has expired */
+	if (time_before_eq(base->next_timer, jiffies))
+		raise_softirq(TIMER_SOFTIRQ);
+out:
+#ifdef CONFIG_PREEMPT_RT_FULL
+	rt_spin_unlock(&base->lock);
+#endif
+	/* The ; ensures that gcc won't complain in the !RT case */
+	;
 }
 
 #ifdef __ARCH_WANT_SYS_ALARM