hrtimer: unlock hrtimer_wakeup

hrtimer_wakeup creates a base->lock rq->lock lock dependancy. Avoid this by switching to HRTIMER_CB_IRQSAFE_NO_SOFTIRQ which doesn't hold base->lock. This fully untangles hrtimer locks from the scheduler locks, and allows hrtimer usage in the scheduler proper. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>

hrtimer: unlock hrtimer_wakeup
hrtimer_wakeup creates a base->lock rq->lock lock dependancy. Avoid this by switching to HRTIMER_CB_IRQSAFE_NO_SOFTIRQ which doesn't hold base->lock. This fully untangles hrtimer locks from the scheduler locks, and allows hrtimer usage in the scheduler proper. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Peter Zijlstra · Ingo Molnar
1 parent d3d74453c3
Showing 1 changed file with 3 additions and 1 deletions Side-by-side Diff
kernel/hrtimer.c
@@ -1293,7 +1293,7 @@
 	sl->timer.function = hrtimer_wakeup;
 	sl->task = task;
 #ifdef CONFIG_HIGH_RES_TIMERS
-	sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_RESTART;
+	sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
 #endif
 }
  
@@ -1304,6 +1304,8 @@
 	do {
 		set_current_state(TASK_INTERRUPTIBLE);
 		hrtimer_start(&t->timer, t->timer.expires, mode);
+		if (!hrtimer_active(&t->timer))
+			t->task = NULL;
  
 		if (likely(t->task))
 			schedule();
...	...	@@ -1293,7 +1293,7 @@
1293	1293	sl->timer.function = hrtimer_wakeup;
1294	1294	sl->task = task;
1295	1295	#ifdef CONFIG_HIGH_RES_TIMERS
1296		- sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_RESTART;
	1296	+ sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
1297	1297	#endif
1298	1298	}
1299	1299
...	...	@@ -1304,6 +1304,8 @@
1304	1304	do {
1305	1305	set_current_state(TASK_INTERRUPTIBLE);
1306	1306	hrtimer_start(&t->timer, t->timer.expires, mode);
	1307	+ if (!hrtimer_active(&t->timer))
	1308	+ t->task = NULL;
1307	1309
1308	1310	if (likely(t->task))
1309	1311	schedule();