diff options
| -rw-r--r-- | include/linux/hrtimer.h | 3 | ||||
| -rw-r--r-- | kernel/hrtimer.c | 190 | ||||
| -rw-r--r-- | kernel/sched/core.c | 1 | ||||
| -rw-r--r-- | kernel/sched/rt.c | 1 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 1 | ||||
| -rw-r--r-- | kernel/watchdog.c | 1 |
6 files changed, 179 insertions, 18 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index e8b395d556b9..0e3708636ce0 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -111,6 +111,8 @@ struct hrtimer { enum hrtimer_restart (*function)(struct hrtimer *); struct hrtimer_clock_base *base; unsigned long state; + struct list_head cb_entry; + int irqsafe; #ifdef CONFIG_TIMER_STATS int start_pid; void *start_site; @@ -147,6 +149,7 @@ struct hrtimer_clock_base { int index; clockid_t clockid; struct timerqueue_head active; + struct list_head expired; ktime_t resolution; ktime_t (*get_time)(void); ktime_t softirq_time; diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 905e2cd2af72..1dd627ba799e 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -589,8 +589,7 @@ static int hrtimer_reprogram(struct hrtimer *timer, * When the callback is running, we do not reprogram the clock event * device. The timer callback is either running on a different CPU or * the callback is executed in the hrtimer_interrupt context. The - * reprogramming is handled either by the softirq, which called the - * callback or at the end of the hrtimer_interrupt. + * reprogramming is handled at the end of the hrtimer_interrupt. */ if (hrtimer_callback_running(timer)) return 0; @@ -625,6 +624,9 @@ static int hrtimer_reprogram(struct hrtimer *timer, return res; } +static void __run_hrtimer(struct hrtimer *timer, ktime_t *now); +static int hrtimer_rt_defer(struct hrtimer *timer); + /* * Initialize the high resolution related parts of cpu_base */ @@ -644,7 +646,29 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, struct hrtimer_clock_base *base, int wakeup) { +#ifdef CONFIG_PREEMPT_RT_BASE +again: + if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) { + /* + * Move softirq based timers away from the rbtree in + * case it expired already. Otherwise we would have a + * stale base->first entry until the softirq runs. + */ + if (!hrtimer_rt_defer(timer)) { + ktime_t now = ktime_get(); + + __run_hrtimer(timer, &now); + /* + * __run_hrtimer might have requeued timer and + * it could be base->first again. + */ + if (&timer->node == base->active.next) + goto again; + return 1; + } +#else if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) { +#endif if (wakeup) { raw_spin_unlock(&base->cpu_base->lock); raise_softirq_irqoff(HRTIMER_SOFTIRQ); @@ -733,6 +757,11 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, } static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { } static inline void retrigger_next_event(void *arg) { } +static inline int hrtimer_reprogram(struct hrtimer *timer, + struct hrtimer_clock_base *base) +{ + return 0; +} #endif /* CONFIG_HIGH_RES_TIMERS */ @@ -864,9 +893,9 @@ void hrtimer_wait_for_timer(const struct hrtimer *timer) { struct hrtimer_clock_base *base = timer->base; - if (base && base->cpu_base && !hrtimer_hres_active(base->cpu_base)) + if (base && base->cpu_base && !timer->irqsafe) wait_event(base->cpu_base->wait, - !(timer->state & HRTIMER_STATE_CALLBACK)); + !(timer->state & HRTIMER_STATE_CALLBACK)); } #else @@ -916,6 +945,11 @@ static void __remove_hrtimer(struct hrtimer *timer, if (!(timer->state & HRTIMER_STATE_ENQUEUED)) goto out; + if (unlikely(!list_empty(&timer->cb_entry))) { + list_del_init(&timer->cb_entry); + goto out; + } + next_timer = timerqueue_getnext(&base->active); timerqueue_del(&base->active, &timer->node); if (&timer->node == next_timer) { @@ -1178,6 +1212,7 @@ static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id, base = hrtimer_clockid_to_base(clock_id); timer->base = &cpu_base->clock_base[base]; + INIT_LIST_HEAD(&timer->cb_entry); timerqueue_init(&timer->node); #ifdef CONFIG_TIMER_STATS @@ -1261,10 +1296,118 @@ static void __run_hrtimer(struct hrtimer *timer, ktime_t *now) timer->state &= ~HRTIMER_STATE_CALLBACK; } -#ifdef CONFIG_HIGH_RES_TIMERS - static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer); +#ifdef CONFIG_PREEMPT_RT_BASE +static void hrtimer_rt_reprogram(int restart, struct hrtimer *timer, + struct hrtimer_clock_base *base) +{ + /* + * Note, we clear the callback flag before we requeue the + * timer otherwise we trigger the callback_running() check + * in hrtimer_reprogram(). + */ + timer->state &= ~HRTIMER_STATE_CALLBACK; + + if (restart != HRTIMER_NORESTART) { + BUG_ON(hrtimer_active(timer)); + /* + * Enqueue the timer, if it's the leftmost timer then + * we need to reprogram it. + */ + if (!enqueue_hrtimer(timer, base)) + return; + + if (hrtimer_reprogram(timer, base)) + goto requeue; + + } else if (hrtimer_active(timer)) { + /* + * If the timer was rearmed on another CPU, reprogram + * the event device. + */ + if (&timer->node == base->active.next && + hrtimer_reprogram(timer, base)) + goto requeue; + } + return; + +requeue: + /* + * Timer is expired. Thus move it from tree to pending list + * again. + */ + __remove_hrtimer(timer, base, timer->state, 0); + list_add_tail(&timer->cb_entry, &base->expired); +} + +/* + * The changes in mainline which removed the callback modes from + * hrtimer are not yet working with -rt. The non wakeup_process() + * based callbacks which involve sleeping locks need to be treated + * seperately. + */ +static void hrtimer_rt_run_pending(void) +{ + enum hrtimer_restart (*fn)(struct hrtimer *); + struct hrtimer_cpu_base *cpu_base; + struct hrtimer_clock_base *base; + struct hrtimer *timer; + int index, restart; + + local_irq_disable(); + cpu_base = &per_cpu(hrtimer_bases, smp_processor_id()); + + raw_spin_lock(&cpu_base->lock); + + for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) { + base = &cpu_base->clock_base[index]; + + while (!list_empty(&base->expired)) { + timer = list_first_entry(&base->expired, + struct hrtimer, cb_entry); + + /* + * Same as the above __run_hrtimer function + * just we run with interrupts enabled. + */ + debug_hrtimer_deactivate(timer); + __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0); + timer_stats_account_hrtimer(timer); + fn = timer->function; + + raw_spin_unlock_irq(&cpu_base->lock); + restart = fn(timer); + raw_spin_lock_irq(&cpu_base->lock); + + hrtimer_rt_reprogram(restart, timer, base); + } + } + + raw_spin_unlock_irq(&cpu_base->lock); + + wake_up_timer_waiters(cpu_base); +} + +static int hrtimer_rt_defer(struct hrtimer *timer) +{ + if (timer->irqsafe) + return 0; + + __remove_hrtimer(timer, timer->base, timer->state, 0); + list_add_tail(&timer->cb_entry, &timer->base->expired); + return 1; +} + +#else + +static inline void hrtimer_rt_run_pending(void) { } +static inline int hrtimer_rt_defer(struct hrtimer *timer) { return 0; } + +#endif + +#ifdef CONFIG_HIGH_RES_TIMERS + /* * High resolution timer interrupt * Called with interrupts disabled @@ -1273,7 +1416,7 @@ void hrtimer_interrupt(struct clock_event_device *dev) { struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); ktime_t expires_next, now, entry_time, delta; - int i, retries = 0; + int i, retries = 0, raise = 0; BUG_ON(!cpu_base->hres_active); cpu_base->nr_events++; @@ -1340,7 +1483,10 @@ retry: break; } - __run_hrtimer(timer, &basenow); + if (!hrtimer_rt_defer(timer)) + __run_hrtimer(timer, &basenow); + else + raise = 1; } } @@ -1355,6 +1501,10 @@ retry: if (expires_next.tv64 == KTIME_MAX || !tick_program_event(expires_next, 0)) { cpu_base->hang_detected = 0; + + if (raise) + raise_softirq_irqoff(HRTIMER_SOFTIRQ); + return; } @@ -1430,17 +1580,17 @@ void hrtimer_peek_ahead_timers(void) local_irq_restore(flags); } -static void run_hrtimer_softirq(struct softirq_action *h) -{ - hrtimer_peek_ahead_timers(); -} - #else /* CONFIG_HIGH_RES_TIMERS */ static inline void __hrtimer_peek_ahead_timers(void) { } #endif /* !CONFIG_HIGH_RES_TIMERS */ +static void run_hrtimer_softirq(struct softirq_action *h) +{ + hrtimer_rt_run_pending(); +} + /* * Called from timer softirq every jiffy, expire hrtimers: * @@ -1473,7 +1623,7 @@ void hrtimer_run_queues(void) struct timerqueue_node *node; struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); struct hrtimer_clock_base *base; - int index, gettime = 1; + int index, gettime = 1, raise = 0; if (hrtimer_hres_active()) return; @@ -1498,12 +1648,16 @@ void hrtimer_run_queues(void) hrtimer_get_expires_tv64(timer)) break; - __run_hrtimer(timer, &base->softirq_time); + if (!hrtimer_rt_defer(timer)) + __run_hrtimer(timer, &base->softirq_time); + else + raise = 1; } raw_spin_unlock(&cpu_base->lock); } - wake_up_timer_waiters(cpu_base); + if (raise) + raise_softirq_irqoff(HRTIMER_SOFTIRQ); } /* @@ -1525,6 +1679,7 @@ static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer) void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task) { sl->timer.function = hrtimer_wakeup; + sl->timer.irqsafe = 1; sl->task = task; } EXPORT_SYMBOL_GPL(hrtimer_init_sleeper); @@ -1663,6 +1818,7 @@ static void __cpuinit init_hrtimers_cpu(int cpu) for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) { cpu_base->clock_base[i].cpu_base = cpu_base; timerqueue_init_head(&cpu_base->clock_base[i].active); + INIT_LIST_HEAD(&cpu_base->clock_base[i].expired); } hrtimer_init_hres(cpu_base); @@ -1781,9 +1937,7 @@ void __init hrtimers_init(void) hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE, (void *)(long)smp_processor_id()); register_cpu_notifier(&hrtimers_nb); -#ifdef CONFIG_HIGH_RES_TIMERS open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq); -#endif } /** diff --git a/kernel/sched/core.c b/kernel/sched/core.c index df06ea68e2b8..65c44bf92679 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -480,6 +480,7 @@ static void init_rq_hrtick(struct rq *rq) hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); rq->hrtick_timer.function = hrtick; + rq->hrtick_timer.irqsafe = 1; } #else /* CONFIG_SCHED_HRTICK */ static inline void hrtick_clear(struct rq *rq) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 44af55e6d5d0..8bb9f00f8b49 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -41,6 +41,7 @@ void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime) hrtimer_init(&rt_b->rt_period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + rt_b->rt_period_timer.irqsafe = 1; rt_b->rt_period_timer.function = sched_rt_period_timer; } diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 6d44f87f83ed..e94b6b33123a 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -830,6 +830,7 @@ void tick_setup_sched_timer(void) * Emulate tick processing via per-CPU hrtimers: */ hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); + ts->sched_timer.irqsafe = 1; ts->sched_timer.function = tick_sched_timer; /* Get the next period (per cpu) */ diff --git a/kernel/watchdog.c b/kernel/watchdog.c index de08263ff8ae..87192eb940c0 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -441,6 +441,7 @@ static void watchdog_prepare_cpu(int cpu) WARN_ON(per_cpu(softlockup_watchdog, cpu)); hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); hrtimer->function = watchdog_timer_fn; + hrtimer->irqsafe = 1; } static int watchdog_enable(int cpu) |