Commit f8acc450 authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fix from Thomas Gleixner:
 "Fix a potential deadlock versus hrtimers"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Fix HRTICK
parents 505608d2 971ee28c
...@@ -370,13 +370,6 @@ static struct rq *this_rq_lock(void) ...@@ -370,13 +370,6 @@ static struct rq *this_rq_lock(void)
#ifdef CONFIG_SCHED_HRTICK #ifdef CONFIG_SCHED_HRTICK
/* /*
* Use HR-timers to deliver accurate preemption points. * Use HR-timers to deliver accurate preemption points.
*
* Its all a bit involved since we cannot program an hrt while holding the
* rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
* reschedule event.
*
* When we get rescheduled we reprogram the hrtick_timer outside of the
* rq->lock.
*/ */
static void hrtick_clear(struct rq *rq) static void hrtick_clear(struct rq *rq)
...@@ -404,6 +397,15 @@ static enum hrtimer_restart hrtick(struct hrtimer *timer) ...@@ -404,6 +397,15 @@ static enum hrtimer_restart hrtick(struct hrtimer *timer)
} }
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
static int __hrtick_restart(struct rq *rq)
{
struct hrtimer *timer = &rq->hrtick_timer;
ktime_t time = hrtimer_get_softexpires(timer);
return __hrtimer_start_range_ns(timer, time, 0, HRTIMER_MODE_ABS_PINNED, 0);
}
/* /*
* called from hardirq (IPI) context * called from hardirq (IPI) context
*/ */
...@@ -412,7 +414,7 @@ static void __hrtick_start(void *arg) ...@@ -412,7 +414,7 @@ static void __hrtick_start(void *arg)
struct rq *rq = arg; struct rq *rq = arg;
raw_spin_lock(&rq->lock); raw_spin_lock(&rq->lock);
hrtimer_restart(&rq->hrtick_timer); __hrtick_restart(rq);
rq->hrtick_csd_pending = 0; rq->hrtick_csd_pending = 0;
raw_spin_unlock(&rq->lock); raw_spin_unlock(&rq->lock);
} }
...@@ -430,7 +432,7 @@ void hrtick_start(struct rq *rq, u64 delay) ...@@ -430,7 +432,7 @@ void hrtick_start(struct rq *rq, u64 delay)
hrtimer_set_expires(timer, time); hrtimer_set_expires(timer, time);
if (rq == this_rq()) { if (rq == this_rq()) {
hrtimer_restart(timer); __hrtick_restart(rq);
} else if (!rq->hrtick_csd_pending) { } else if (!rq->hrtick_csd_pending) {
__smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0); __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
rq->hrtick_csd_pending = 1; rq->hrtick_csd_pending = 1;
......
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