static void migrate_hrtimers(int cpu)
{
struct hrtimer_cpu_base *old_base, *new_base;
int i, raise = 0;
BUG_ON(cpu_online(cpu));
old_base = &per_cpu(hrtimer_bases, cpu);
new_base = &get_cpu_var(hrtimer_bases);
tick_cancel_sched_timer(cpu);
/*
* The caller is globally serialized and nobody else
* takes two locks at once, deadlock is not possible.
*/
spin_lock_irq(&new_base->lock);
spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
if (migrate_hrtimer_list(&old_base->clock_base[i],
&new_base->clock_base[i], cpu))
raise = 1;
}
if (migrate_hrtimer_pending(old_base, new_base))
raise = 1;
spin_unlock(&old_base->lock);
spin_unlock_irq(&new_base->lock);
put_cpu_var(hrtimer_bases);
if (raise)
hrtimer_raise_softirq();
}
/**
* hrtimer_start - (re)start an relative timer on the current CPU
* @timer: the timer to be added
* @tim: expiry time
* @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
*
* Returns:
* 0 on success
* 1 when the timer was active
*/
int
hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
{
struct hrtimer_clock_base *base, *new_base;
unsigned long flags;
int ret, raise;
base = lock_hrtimer_base(timer, &flags);
/* Remove an active timer from the queue: */
ret = remove_hrtimer(timer, base);
/* Switch the timer base, if necessary: */
new_base = switch_hrtimer_base(timer, base);
if (mode == HRTIMER_MODE_REL) {
tim = ktime_add_safe(tim, new_base->get_time());
/*
* CONFIG_TIME_LOW_RES is a temporary way for architectures
* to signal that they simply return xtime in
* do_gettimeoffset(). In this case we want to round up by
* resolution when starting a relative timer, to avoid short
* timeouts. This will go away with the GTOD framework.
*/
#ifdef CONFIG_TIME_LOW_RES
tim = ktime_add_safe(tim, base->resolution);
#endif
}
timer->expires = tim;
timer_stats_hrtimer_set_start_info(timer);
/*
* Only allow reprogramming if the new base is on this CPU.
* (it might still be on another CPU if the timer was pending)
*/
enqueue_hrtimer(timer, new_base,
new_base->cpu_base == &__get_cpu_var(hrtimer_bases));
/*
* The timer may be expired and moved to the cb_pending
* list. We can not raise the softirq with base lock held due
* to a possible deadlock with runqueue lock.
*/
raise = timer->state == HRTIMER_STATE_PENDING;
unlock_hrtimer_base(timer, &flags);
if (raise)
hrtimer_raise_softirq();
return ret;
}
