diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/hrtimer.c | 6 | ||||
| -rw-r--r-- | kernel/time/tick-broadcast.c | 225 | ||||
| -rw-r--r-- | kernel/time/tick-common.c | 1 | ||||
| -rw-r--r-- | kernel/time/tick-internal.h | 3 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 4 |
5 files changed, 179 insertions, 60 deletions
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 258720741d3..d6830d5ae73 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -1022,7 +1022,8 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, * @timer: the timer to be added * @tim: expiry time * @delta_ns: "slack" range for the timer - * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL) + * @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or + * relative (HRTIMER_MODE_REL) * * Returns: * 0 on success @@ -1039,7 +1040,8 @@ EXPORT_SYMBOL_GPL(hrtimer_start_range_ns); * hrtimer_start - (re)start an hrtimer on the current CPU * @timer: the timer to be added * @tim: expiry time - * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL) + * @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or + * relative (HRTIMER_MODE_REL) * * Returns: * 0 on success diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 2fb8cb88df8..d76d816afc5 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -28,9 +28,8 @@ */ 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; @@ -50,7 +49,7 @@ struct tick_device *tick_get_broadcast_device(void) struct cpumask *tick_get_broadcast_mask(void) { - return to_cpumask(tick_broadcast_mask); + return tick_broadcast_mask; } /* @@ -74,7 +73,7 @@ int tick_check_broadcast_device(struct clock_event_device *dev) clockevents_exchange_device(tick_broadcast_device.evtdev, dev); tick_broadcast_device.evtdev = dev; - if (!cpumask_empty(tick_get_broadcast_mask())) + if (!cpumask_empty(tick_broadcast_mask)) tick_broadcast_start_periodic(dev); return 1; } @@ -123,7 +122,7 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) 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 { @@ -134,7 +133,7 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) */ 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); @@ -198,9 +197,8 @@ static void tick_do_periodic_broadcast(void) { 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); } @@ -263,13 +261,12 @@ static void tick_do_broadcast_on_off(unsigned long *reason) 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); @@ -279,8 +276,7 @@ static void tick_do_broadcast_on_off(unsigned long *reason) 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); @@ -288,7 +284,7 @@ static void tick_do_broadcast_on_off(unsigned long *reason) break; } - if (cpumask_empty(tick_get_broadcast_mask())) { + if (cpumask_empty(tick_broadcast_mask)) { if (!bc_stopped) clockevents_shutdown(bc); } else if (bc_stopped) { @@ -337,10 +333,10 @@ void tick_shutdown_broadcast(unsigned int *cpup) 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); } @@ -376,13 +372,13 @@ int tick_resume_broadcast(void) 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; } @@ -395,25 +391,58 @@ int tick_resume_broadcast(void) #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) @@ -428,7 +457,7 @@ 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); @@ -442,27 +471,39 @@ static void tick_handle_oneshot_broadcast(struct clock_event_device *dev) { 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: @@ -479,7 +520,7 @@ again: * 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); @@ -494,6 +535,7 @@ void tick_broadcast_oneshot_control(unsigned long reason) struct clock_event_device *bc, *dev; struct tick_device *td; unsigned long flags; + ktime_t now; int cpu; /* @@ -518,21 +560,84 @@ void tick_broadcast_oneshot_control(unsigned long reason) 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); } @@ -543,7 +648,7 @@ void tick_broadcast_oneshot_control(unsigned long reason) */ 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, @@ -581,17 +686,16 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc) * 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 { @@ -639,7 +743,7 @@ void tick_shutdown_broadcast_oneshot(unsigned int *cpup) * 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); } @@ -663,3 +767,14 @@ bool tick_broadcast_oneshot_available(void) } #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 +} diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index b1600a6973f..74413e396ac 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -416,4 +416,5 @@ static struct notifier_block tick_notifier = { void __init tick_init(void) { clockevents_register_notifier(&tick_notifier); + tick_broadcast_init(); } diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h index f5c9207967c..f0299eae460 100644 --- a/kernel/time/tick-internal.h +++ b/kernel/time/tick-internal.h @@ -96,7 +96,7 @@ extern void tick_broadcast_on_off(unsigned long reason, int *oncpu); extern void tick_shutdown_broadcast(unsigned int *cpup); extern void tick_suspend_broadcast(void); extern int tick_resume_broadcast(void); - +extern void tick_broadcast_init(void); extern void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast); @@ -121,6 +121,7 @@ static inline void tick_broadcast_on_off(unsigned long reason, int *oncpu) { } static inline void tick_shutdown_broadcast(unsigned int *cpup) { } static inline void tick_suspend_broadcast(void) { } static inline int tick_resume_broadcast(void) { return 0; } +static inline void tick_broadcast_init(void) { } /* * Set the periodic handler in non broadcast mode diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index a19a39952c1..225f8bf1909 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -482,8 +482,8 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched *ts) if (ratelimit < 10 && (local_softirq_pending() & SOFTIRQ_STOP_IDLE_MASK)) { - printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n", - (unsigned int) local_softirq_pending()); + pr_warn("NOHZ: local_softirq_pending %02x\n", + (unsigned int) local_softirq_pending()); ratelimit++; } return false; |