*/
static struct tick_device tick_broadcast_device;
-/* FIXME: Use cpumask_var_t. */
-static DECLARE_BITMAP(tick_broadcast_mask, NR_CPUS);
-static DECLARE_BITMAP(tmpmask, NR_CPUS);
+static cpumask_var_t tick_broadcast_mask;
+static cpumask_var_t tmpmask;
static DEFINE_RAW_SPINLOCK(tick_broadcast_lock);
static int tick_broadcast_force;
struct cpumask *tick_get_broadcast_mask(void)
{
- return to_cpumask(tick_broadcast_mask);
+ return tick_broadcast_mask;
}
/*
*/
int tick_check_broadcast_device(struct clock_event_device *dev)
{
+ struct clock_event_device *cur = tick_broadcast_device.evtdev;
+
if ((dev->features & CLOCK_EVT_FEAT_DUMMY) ||
(tick_broadcast_device.evtdev &&
tick_broadcast_device.evtdev->rating >= dev->rating) ||
return 0;
clockevents_exchange_device(tick_broadcast_device.evtdev, dev);
+ if (cur)
+ cur->event_handler = clockevents_handle_noop;
tick_broadcast_device.evtdev = dev;
- if (!cpumask_empty(tick_get_broadcast_mask()))
+ if (!cpumask_empty(tick_broadcast_mask))
tick_broadcast_start_periodic(dev);
+ /*
+ * Inform all cpus about this. We might be in a situation
+ * where we did not switch to oneshot mode because the per cpu
+ * devices are affected by CLOCK_EVT_FEAT_C3STOP and the lack
+ * of a oneshot capable broadcast device. Without that
+ * notification the systems stays stuck in periodic mode
+ * forever.
+ */
+ if (dev->features & CLOCK_EVT_FEAT_ONESHOT)
+ tick_clock_notify();
return 1;
}
if (!tick_device_is_functional(dev)) {
dev->event_handler = tick_handle_periodic;
tick_device_setup_broadcast_func(dev);
- cpumask_set_cpu(cpu, tick_get_broadcast_mask());
+ cpumask_set_cpu(cpu, tick_broadcast_mask);
tick_broadcast_start_periodic(tick_broadcast_device.evtdev);
ret = 1;
} else {
*/
if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) {
int cpu = smp_processor_id();
- cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
+ cpumask_clear_cpu(cpu, tick_broadcast_mask);
tick_broadcast_clear_oneshot(cpu);
} else {
tick_device_setup_broadcast_func(dev);
{
raw_spin_lock(&tick_broadcast_lock);
- cpumask_and(to_cpumask(tmpmask),
- cpu_online_mask, tick_get_broadcast_mask());
- tick_do_broadcast(to_cpumask(tmpmask));
+ cpumask_and(tmpmask, cpu_online_mask, tick_broadcast_mask);
+ tick_do_broadcast(tmpmask);
raw_spin_unlock(&tick_broadcast_lock);
}
if (!tick_device_is_functional(dev))
goto out;
- bc_stopped = cpumask_empty(tick_get_broadcast_mask());
+ bc_stopped = cpumask_empty(tick_broadcast_mask);
switch (*reason) {
case CLOCK_EVT_NOTIFY_BROADCAST_ON:
case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
- if (!cpumask_test_cpu(cpu, tick_get_broadcast_mask())) {
- cpumask_set_cpu(cpu, tick_get_broadcast_mask());
+ if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_mask)) {
if (tick_broadcast_device.mode ==
TICKDEV_MODE_PERIODIC)
clockevents_shutdown(dev);
break;
case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
if (!tick_broadcast_force &&
- cpumask_test_cpu(cpu, tick_get_broadcast_mask())) {
- cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
+ cpumask_test_and_clear_cpu(cpu, tick_broadcast_mask)) {
if (tick_broadcast_device.mode ==
TICKDEV_MODE_PERIODIC)
tick_setup_periodic(dev, 0);
break;
}
- if (cpumask_empty(tick_get_broadcast_mask())) {
+ if (cpumask_empty(tick_broadcast_mask)) {
if (!bc_stopped)
clockevents_shutdown(bc);
} else if (bc_stopped) {
raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
bc = tick_broadcast_device.evtdev;
- cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
+ cpumask_clear_cpu(cpu, tick_broadcast_mask);
if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
- if (bc && cpumask_empty(tick_get_broadcast_mask()))
+ if (bc && cpumask_empty(tick_broadcast_mask))
clockevents_shutdown(bc);
}
switch (tick_broadcast_device.mode) {
case TICKDEV_MODE_PERIODIC:
- if (!cpumask_empty(tick_get_broadcast_mask()))
+ if (!cpumask_empty(tick_broadcast_mask))
tick_broadcast_start_periodic(bc);
broadcast = cpumask_test_cpu(smp_processor_id(),
- tick_get_broadcast_mask());
+ tick_broadcast_mask);
break;
case TICKDEV_MODE_ONESHOT:
- if (!cpumask_empty(tick_get_broadcast_mask()))
+ if (!cpumask_empty(tick_broadcast_mask))
broadcast = tick_resume_broadcast_oneshot(bc);
break;
}
#ifdef CONFIG_TICK_ONESHOT
-/* FIXME: use cpumask_var_t. */
-static DECLARE_BITMAP(tick_broadcast_oneshot_mask, NR_CPUS);
+static cpumask_var_t tick_broadcast_oneshot_mask;
+static cpumask_var_t tick_broadcast_pending_mask;
+static cpumask_var_t tick_broadcast_force_mask;
/*
* Exposed for debugging: see timer_list.c
*/
struct cpumask *tick_get_broadcast_oneshot_mask(void)
{
- return to_cpumask(tick_broadcast_oneshot_mask);
+ return tick_broadcast_oneshot_mask;
}
-static int tick_broadcast_set_event(ktime_t expires, int force)
+/*
+ * Called before going idle with interrupts disabled. Checks whether a
+ * broadcast event from the other core is about to happen. We detected
+ * that in tick_broadcast_oneshot_control(). The callsite can use this
+ * to avoid a deep idle transition as we are about to get the
+ * broadcast IPI right away.
+ */
+int tick_check_broadcast_expired(void)
{
- struct clock_event_device *bc = tick_broadcast_device.evtdev;
+ return cpumask_test_cpu(smp_processor_id(), tick_broadcast_force_mask);
+}
+
+/*
+ * Set broadcast interrupt affinity
+ */
+static void tick_broadcast_set_affinity(struct clock_event_device *bc,
+ const struct cpumask *cpumask)
+{
+ if (!(bc->features & CLOCK_EVT_FEAT_DYNIRQ))
+ return;
+
+ if (cpumask_equal(bc->cpumask, cpumask))
+ return;
+
+ bc->cpumask = cpumask;
+ irq_set_affinity(bc->irq, bc->cpumask);
+}
+
+static int tick_broadcast_set_event(struct clock_event_device *bc, int cpu,
+ ktime_t expires, int force)
+{
+ int ret;
if (bc->mode != CLOCK_EVT_MODE_ONESHOT)
clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
- return clockevents_program_event(bc, expires, force);
+ ret = clockevents_program_event(bc, expires, force);
+ if (!ret)
+ tick_broadcast_set_affinity(bc, cpumask_of(cpu));
+ return ret;
}
int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
*/
void tick_check_oneshot_broadcast(int cpu)
{
- if (cpumask_test_cpu(cpu, to_cpumask(tick_broadcast_oneshot_mask))) {
+ if (cpumask_test_cpu(cpu, tick_broadcast_oneshot_mask)) {
struct tick_device *td = &per_cpu(tick_cpu_device, cpu);
clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_ONESHOT);
{
struct tick_device *td;
ktime_t now, next_event;
- int cpu;
+ int cpu, next_cpu = 0;
raw_spin_lock(&tick_broadcast_lock);
again:
dev->next_event.tv64 = KTIME_MAX;
next_event.tv64 = KTIME_MAX;
- cpumask_clear(to_cpumask(tmpmask));
+ cpumask_clear(tmpmask);
now = ktime_get();
/* Find all expired events */
- for_each_cpu(cpu, tick_get_broadcast_oneshot_mask()) {
+ for_each_cpu(cpu, tick_broadcast_oneshot_mask) {
td = &per_cpu(tick_cpu_device, cpu);
- if (td->evtdev->next_event.tv64 <= now.tv64)
- cpumask_set_cpu(cpu, to_cpumask(tmpmask));
- else if (td->evtdev->next_event.tv64 < next_event.tv64)
+ if (td->evtdev->next_event.tv64 <= now.tv64) {
+ cpumask_set_cpu(cpu, tmpmask);
+ /*
+ * Mark the remote cpu in the pending mask, so
+ * it can avoid reprogramming the cpu local
+ * timer in tick_broadcast_oneshot_control().
+ */
+ cpumask_set_cpu(cpu, tick_broadcast_pending_mask);
+ } else if (td->evtdev->next_event.tv64 < next_event.tv64) {
next_event.tv64 = td->evtdev->next_event.tv64;
+ next_cpu = cpu;
+ }
}
+ /* Take care of enforced broadcast requests */
+ cpumask_or(tmpmask, tmpmask, tick_broadcast_force_mask);
+ cpumask_clear(tick_broadcast_force_mask);
+
/*
* Wakeup the cpus which have an expired event.
*/
- tick_do_broadcast(to_cpumask(tmpmask));
+ tick_do_broadcast(tmpmask);
/*
* Two reasons for reprogram:
* Rearm the broadcast device. If event expired,
* repeat the above
*/
- if (tick_broadcast_set_event(next_event, 0))
+ if (tick_broadcast_set_event(dev, next_cpu, next_event, 0))
goto again;
}
raw_spin_unlock(&tick_broadcast_lock);
struct clock_event_device *bc, *dev;
struct tick_device *td;
unsigned long flags;
+ ktime_t now;
int cpu;
/*
raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
- if (!cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) {
- cpumask_set_cpu(cpu, tick_get_broadcast_oneshot_mask());
+ WARN_ON_ONCE(cpumask_test_cpu(cpu, tick_broadcast_pending_mask));
+ if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_oneshot_mask)) {
clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
- if (dev->next_event.tv64 < bc->next_event.tv64)
- tick_broadcast_set_event(dev->next_event, 1);
+ /*
+ * We only reprogram the broadcast timer if we
+ * did not mark ourself in the force mask and
+ * if the cpu local event is earlier than the
+ * broadcast event. If the current CPU is in
+ * the force mask, then we are going to be
+ * woken by the IPI right away.
+ */
+ if (!cpumask_test_cpu(cpu, tick_broadcast_force_mask) &&
+ dev->next_event.tv64 < bc->next_event.tv64)
+ tick_broadcast_set_event(bc, cpu, dev->next_event, 1);
}
} else {
- if (cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) {
- cpumask_clear_cpu(cpu,
- tick_get_broadcast_oneshot_mask());
+ if (cpumask_test_and_clear_cpu(cpu, tick_broadcast_oneshot_mask)) {
clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
- if (dev->next_event.tv64 != KTIME_MAX)
- tick_program_event(dev->next_event, 1);
+ if (dev->next_event.tv64 == KTIME_MAX)
+ goto out;
+ /*
+ * The cpu which was handling the broadcast
+ * timer marked this cpu in the broadcast
+ * pending mask and fired the broadcast
+ * IPI. So we are going to handle the expired
+ * event anyway via the broadcast IPI
+ * handler. No need to reprogram the timer
+ * with an already expired event.
+ */
+ if (cpumask_test_and_clear_cpu(cpu,
+ tick_broadcast_pending_mask))
+ goto out;
+
+ /*
+ * If the pending bit is not set, then we are
+ * either the CPU handling the broadcast
+ * interrupt or we got woken by something else.
+ *
+ * We are not longer in the broadcast mask, so
+ * if the cpu local expiry time is already
+ * reached, we would reprogram the cpu local
+ * timer with an already expired event.
+ *
+ * This can lead to a ping-pong when we return
+ * to idle and therefor rearm the broadcast
+ * timer before the cpu local timer was able
+ * to fire. This happens because the forced
+ * reprogramming makes sure that the event
+ * will happen in the future and depending on
+ * the min_delta setting this might be far
+ * enough out that the ping-pong starts.
+ *
+ * If the cpu local next_event has expired
+ * then we know that the broadcast timer
+ * next_event has expired as well and
+ * broadcast is about to be handled. So we
+ * avoid reprogramming and enforce that the
+ * broadcast handler, which did not run yet,
+ * will invoke the cpu local handler.
+ *
+ * We cannot call the handler directly from
+ * here, because we might be in a NOHZ phase
+ * and we did not go through the irq_enter()
+ * nohz fixups.
+ */
+ now = ktime_get();
+ if (dev->next_event.tv64 <= now.tv64) {
+ cpumask_set_cpu(cpu, tick_broadcast_force_mask);
+ goto out;
+ }
+ /*
+ * We got woken by something else. Reprogram
+ * the cpu local timer device.
+ */
+ tick_program_event(dev->next_event, 1);
}
}
+out:
raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}
*/
static void tick_broadcast_clear_oneshot(int cpu)
{
- cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask());
+ cpumask_clear_cpu(cpu, tick_broadcast_oneshot_mask);
}
static void tick_broadcast_init_next_event(struct cpumask *mask,
bc->event_handler = tick_handle_oneshot_broadcast;
/* Take the do_timer update */
- tick_do_timer_cpu = cpu;
+ if (!tick_nohz_full_cpu(cpu))
+ tick_do_timer_cpu = cpu;
/*
* We must be careful here. There might be other CPUs
* oneshot_mask bits for those and program the
* broadcast device to fire.
*/
- cpumask_copy(to_cpumask(tmpmask), tick_get_broadcast_mask());
- cpumask_clear_cpu(cpu, to_cpumask(tmpmask));
- cpumask_or(tick_get_broadcast_oneshot_mask(),
- tick_get_broadcast_oneshot_mask(),
- to_cpumask(tmpmask));
+ cpumask_copy(tmpmask, tick_broadcast_mask);
+ cpumask_clear_cpu(cpu, tmpmask);
+ cpumask_or(tick_broadcast_oneshot_mask,
+ tick_broadcast_oneshot_mask, tmpmask);
- if (was_periodic && !cpumask_empty(to_cpumask(tmpmask))) {
+ if (was_periodic && !cpumask_empty(tmpmask)) {
clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
- tick_broadcast_init_next_event(to_cpumask(tmpmask),
+ tick_broadcast_init_next_event(tmpmask,
tick_next_period);
- tick_broadcast_set_event(tick_next_period, 1);
+ tick_broadcast_set_event(bc, cpu, tick_next_period, 1);
} else
bc->next_event.tv64 = KTIME_MAX;
} else {
* Clear the broadcast mask flag for the dead cpu, but do not
* stop the broadcast device!
*/
- cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask());
+ cpumask_clear_cpu(cpu, tick_broadcast_oneshot_mask);
raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}
}
#endif
+
+void __init tick_broadcast_init(void)
+{
+ alloc_cpumask_var(&tick_broadcast_mask, GFP_NOWAIT);
+ alloc_cpumask_var(&tmpmask, GFP_NOWAIT);
+#ifdef CONFIG_TICK_ONESHOT
+ alloc_cpumask_var(&tick_broadcast_oneshot_mask, GFP_NOWAIT);
+ alloc_cpumask_var(&tick_broadcast_pending_mask, GFP_NOWAIT);
+ alloc_cpumask_var(&tick_broadcast_force_mask, GFP_NOWAIT);
+#endif
+}
projects / mirror_ubuntu-zesty-kernel.git / blobdiff