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hrtimer: removing all ur callback modes, fix hotplug

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Impact: fix hrtimer locking (reported by lockdep) in the CPU hotplug case

This addition fixes the hotplug locking issue on my machine

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2008-12-04 11:17:10 +01:00 committed by Ingo Molnar
parent ca109491f6
commit 37810659ea
1 changed files with 37 additions and 28 deletions
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65
kernel/hrtimer.c
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@ -1496,7 +1496,7 @@ static void __cpuinit init_hrtimers_cpu(int cpu)
#ifdef CONFIG_HOTPLUG_CPU
static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
struct hrtimer_clock_base *new_base, int dcpu)
struct hrtimer_clock_base *new_base)
{
struct hrtimer *timer;
struct rb_node *node;
@ -1514,40 +1514,34 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
__remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
timer->base = new_base;
/*
* Enqueue the timer. Allow reprogramming of the event device
* Enqueue the timers on the new cpu, but do not reprogram
* the timer as that would enable a deadlock between
* hrtimer_enqueue_reprogramm() running the timer and us still
* holding a nested base lock.
*
* Instead we tickle the hrtimer interrupt after the migration
* is done, which will run all expired timers and re-programm
* the timer device.
*/
enqueue_hrtimer(timer, new_base, 1);
enqueue_hrtimer(timer, new_base, 0);
#ifdef CONFIG_HIGH_RES_TIMERS
/*
* Happens with high res enabled when the timer was
* already expired and the callback mode is
* HRTIMER_CB_IRQSAFE_UNLOCKED (hrtimer_sleeper). The
* enqueue code does not move them to the soft irq
* pending list for performance/latency reasons, but
* in the migration state, we need to do that
* otherwise we end up with a stale timer.
*/
if (timer->state == HRTIMER_STATE_MIGRATE) {
/* XXX: running on offline cpu */
__run_hrtimer(timer);
}
#endif
/* Clear the migration state bit */
timer->state &= ~HRTIMER_STATE_MIGRATE;
}
}
static void migrate_hrtimers(int cpu)
static int migrate_hrtimers(int scpu)
{
struct hrtimer_cpu_base *old_base, *new_base;
int i;
int dcpu, i;
BUG_ON(cpu_online(cpu));
old_base = &per_cpu(hrtimer_bases, cpu);
BUG_ON(cpu_online(scpu));
old_base = &per_cpu(hrtimer_bases, scpu);
new_base = &get_cpu_var(hrtimer_bases);
tick_cancel_sched_timer(cpu);
dcpu = smp_processor_id();
tick_cancel_sched_timer(scpu);
/*
* The caller is globally serialized and nobody else
* takes two locks at once, deadlock is not possible.
@ -1557,32 +1551,47 @@ static void migrate_hrtimers(int cpu)
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
migrate_hrtimer_list(&old_base->clock_base[i],
&new_base->clock_base[i], cpu);
&new_base->clock_base[i]);
}
spin_unlock(&old_base->lock);
spin_unlock_irq(&new_base->lock);
put_cpu_var(hrtimer_bases);
return dcpu;
}
static void tickle_timers(void *arg)
{
hrtimer_peek_ahead_timers();
}
#endif /* CONFIG_HOTPLUG_CPU */
static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
unsigned int cpu = (long)hcpu;
int dcpu = -1, scpu = (long)hcpu;
switch (action) {
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
init_hrtimers_cpu(cpu);
init_hrtimers_cpu(scpu);
break;
#ifdef CONFIG_HOTPLUG_CPU
case CPU_DEAD:
case CPU_DEAD_FROZEN:
clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &cpu);
migrate_hrtimers(cpu);
clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu);
dcpu = migrate_hrtimers(scpu);
break;
case CPU_POST_DEAD:
if (dcpu == -1)
break;
smp_call_function_single(dcpu, tickle_timers, NULL, 0);
break;
#endif