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Subject[PATCH 05/11] 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>
---
kernel/hrtimer.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
Index: linux-2.6/kernel/hrtimer.c
===================================================================
--- linux-2.6.orig/kernel/hrtimer.c
+++ linux-2.6/kernel/hrtimer.c
@@ -1296,7 +1296,7 @@ void hrtimer_init_sleeper(struct hrtimer
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
}

@@ -1307,6 +1307,8 @@ static int __sched do_nanosleep(struct h
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();
--



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