diff options
Diffstat (limited to 'kernel/hrtimer.c')
| -rw-r--r-- | kernel/hrtimer.c | 830 |
1 files changed, 685 insertions, 145 deletions
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index d0ba190dfeb6..476cb0c0b4a4 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -1,8 +1,9 @@ /* * linux/kernel/hrtimer.c * - * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de> - * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar + * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de> + * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar + * Copyright(C) 2006-2007 Timesys Corp., Thomas Gleixner * * High-resolution kernel timers * @@ -31,12 +32,17 @@ */ #include <linux/cpu.h> +#include <linux/irq.h> #include <linux/module.h> #include <linux/percpu.h> #include <linux/hrtimer.h> #include <linux/notifier.h> #include <linux/syscalls.h> +#include <linux/kallsyms.h> #include <linux/interrupt.h> +#include <linux/tick.h> +#include <linux/seq_file.h> +#include <linux/err.h> #include <asm/uaccess.h> @@ -45,7 +51,7 @@ * * returns the time in ktime_t format */ -static ktime_t ktime_get(void) +ktime_t ktime_get(void) { struct timespec now; @@ -59,7 +65,7 @@ static ktime_t ktime_get(void) * * returns the time in ktime_t format */ -static ktime_t ktime_get_real(void) +ktime_t ktime_get_real(void) { struct timespec now; @@ -79,21 +85,22 @@ EXPORT_SYMBOL_GPL(ktime_get_real); * This ensures that we capture erroneous accesses to these clock ids * rather than moving them into the range of valid clock id's. */ - -#define MAX_HRTIMER_BASES 2 - -static DEFINE_PER_CPU(struct hrtimer_base, hrtimer_bases[MAX_HRTIMER_BASES]) = +DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) = { + + .clock_base = { - .index = CLOCK_REALTIME, - .get_time = &ktime_get_real, - .resolution = KTIME_REALTIME_RES, - }, - { - .index = CLOCK_MONOTONIC, - .get_time = &ktime_get, - .resolution = KTIME_MONOTONIC_RES, - }, + { + .index = CLOCK_REALTIME, + .get_time = &ktime_get_real, + .resolution = KTIME_LOW_RES, + }, + { + .index = CLOCK_MONOTONIC, + .get_time = &ktime_get, + .resolution = KTIME_LOW_RES, + }, + } }; /** @@ -102,7 +109,7 @@ static DEFINE_PER_CPU(struct hrtimer_base, hrtimer_bases[MAX_HRTIMER_BASES]) = * * The function calculates the monotonic clock from the realtime * clock and the wall_to_monotonic offset and stores the result - * in normalized timespec format in the variable pointed to by ts. + * in normalized timespec format in the variable pointed to by @ts. */ void ktime_get_ts(struct timespec *ts) { @@ -125,20 +132,35 @@ EXPORT_SYMBOL_GPL(ktime_get_ts); * Get the coarse grained time at the softirq based on xtime and * wall_to_monotonic. */ -static void hrtimer_get_softirq_time(struct hrtimer_base *base) +static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base) { ktime_t xtim, tomono; + struct timespec xts; unsigned long seq; do { seq = read_seqbegin(&xtime_lock); - xtim = timespec_to_ktime(xtime); - tomono = timespec_to_ktime(wall_to_monotonic); - +#ifdef CONFIG_NO_HZ + getnstimeofday(&xts); +#else + xts = xtime; +#endif } while (read_seqretry(&xtime_lock, seq)); - base[CLOCK_REALTIME].softirq_time = xtim; - base[CLOCK_MONOTONIC].softirq_time = ktime_add(xtim, tomono); + xtim = timespec_to_ktime(xts); + tomono = timespec_to_ktime(wall_to_monotonic); + base->clock_base[CLOCK_REALTIME].softirq_time = xtim; + base->clock_base[CLOCK_MONOTONIC].softirq_time = + ktime_add(xtim, tomono); +} + +/* + * Helper function to check, whether the timer is running the callback + * function + */ +static inline int hrtimer_callback_running(struct hrtimer *timer) +{ + return timer->state & HRTIMER_STATE_CALLBACK; } /* @@ -147,8 +169,6 @@ static void hrtimer_get_softirq_time(struct hrtimer_base *base) */ #ifdef CONFIG_SMP -#define set_curr_timer(b, t) do { (b)->curr_timer = (t); } while (0) - /* * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock * means that all timers which are tied to this base via timer->base are @@ -161,19 +181,20 @@ static void hrtimer_get_softirq_time(struct hrtimer_base *base) * possible to set timer->base = NULL and drop the lock: the timer remains * locked. */ -static struct hrtimer_base *lock_hrtimer_base(const struct hrtimer *timer, - unsigned long *flags) +static +struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer, + unsigned long *flags) { - struct hrtimer_base *base; + struct hrtimer_clock_base *base; for (;;) { base = timer->base; if (likely(base != NULL)) { - spin_lock_irqsave(&base->lock, *flags); + spin_lock_irqsave(&base->cpu_base->lock, *flags); if (likely(base == timer->base)) return base; /* The timer has migrated to another CPU: */ - spin_unlock_irqrestore(&base->lock, *flags); + spin_unlock_irqrestore(&base->cpu_base->lock, *flags); } cpu_relax(); } @@ -182,12 +203,14 @@ static struct hrtimer_base *lock_hrtimer_base(const struct hrtimer *timer, /* * Switch the timer base to the current CPU when possible. */ -static inline struct hrtimer_base * -switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_base *base) +static inline struct hrtimer_clock_base * +switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base) { - struct hrtimer_base *new_base; + struct hrtimer_clock_base *new_base; + struct hrtimer_cpu_base *new_cpu_base; - new_base = &__get_cpu_var(hrtimer_bases)[base->index]; + new_cpu_base = &__get_cpu_var(hrtimer_bases); + new_base = &new_cpu_base->clock_base[base->index]; if (base != new_base) { /* @@ -199,13 +222,13 @@ switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_base *base) * completed. There is no conflict as we hold the lock until * the timer is enqueued. */ - if (unlikely(base->curr_timer == timer)) + if (unlikely(hrtimer_callback_running(timer))) return base; /* See the comment in lock_timer_base() */ timer->base = NULL; - spin_unlock(&base->lock); - spin_lock(&new_base->lock); + spin_unlock(&base->cpu_base->lock); + spin_lock(&new_base->cpu_base->lock); timer->base = new_base; } return new_base; @@ -213,19 +236,17 @@ switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_base *base) #else /* CONFIG_SMP */ -#define set_curr_timer(b, t) do { } while (0) - -static inline struct hrtimer_base * +static inline struct hrtimer_clock_base * lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) { - struct hrtimer_base *base = timer->base; + struct hrtimer_clock_base *base = timer->base; - spin_lock_irqsave(&base->lock, *flags); + spin_lock_irqsave(&base->cpu_base->lock, *flags); return base; } -#define switch_hrtimer_base(t, b) (b) +# define switch_hrtimer_base(t, b) (b) #endif /* !CONFIG_SMP */ @@ -256,15 +277,12 @@ ktime_t ktime_add_ns(const ktime_t kt, u64 nsec) return ktime_add(kt, tmp); } - -#else /* CONFIG_KTIME_SCALAR */ - # endif /* !CONFIG_KTIME_SCALAR */ /* * Divide a ktime value by a nanosecond value */ -static unsigned long ktime_divns(const ktime_t kt, s64 div) +unsigned long ktime_divns(const ktime_t kt, s64 div) { u64 dclc, inc, dns; int sft = 0; @@ -281,18 +299,311 @@ static unsigned long ktime_divns(const ktime_t kt, s64 div) return (unsigned long) dclc; } - -#else /* BITS_PER_LONG < 64 */ -# define ktime_divns(kt, div) (unsigned long)((kt).tv64 / (div)) #endif /* BITS_PER_LONG >= 64 */ +/* High resolution timer related functions */ +#ifdef CONFIG_HIGH_RES_TIMERS + +/* + * High resolution timer enabled ? + */ +static int hrtimer_hres_enabled __read_mostly = 1; + +/* + * Enable / Disable high resolution mode + */ +static int __init setup_hrtimer_hres(char *str) +{ + if (!strcmp(str, "off")) + hrtimer_hres_enabled = 0; + else if (!strcmp(str, "on")) + hrtimer_hres_enabled = 1; + else + return 0; + return 1; +} + +__setup("highres=", setup_hrtimer_hres); + +/* + * hrtimer_high_res_enabled - query, if the highres mode is enabled + */ +static inline int hrtimer_is_hres_enabled(void) +{ + return hrtimer_hres_enabled; +} + +/* + * Is the high resolution mode active ? + */ +static inline int hrtimer_hres_active(void) +{ + return __get_cpu_var(hrtimer_bases).hres_active; +} + +/* + * Reprogram the event source with checking both queues for the + * next event + * Called with interrupts disabled and base->lock held + */ +static void hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base) +{ + int i; + struct hrtimer_clock_base *base = cpu_base->clock_base; + ktime_t expires; + + cpu_base->expires_next.tv64 = KTIME_MAX; + + for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) { + struct hrtimer *timer; + + if (!base->first) + continue; + timer = rb_entry(base->first, struct hrtimer, node); + expires = ktime_sub(timer->expires, base->offset); + if (expires.tv64 < cpu_base->expires_next.tv64) + cpu_base->expires_next = expires; + } + + if (cpu_base->expires_next.tv64 != KTIME_MAX) + tick_program_event(cpu_base->expires_next, 1); +} + +/* + * Shared reprogramming for clock_realtime and clock_monotonic + * + * When a timer is enqueued and expires earlier than the already enqueued + * timers, we have to check, whether it expires earlier than the timer for + * which the clock event device was armed. + * + * Called with interrupts disabled and base->cpu_base.lock held + */ +static int hrtimer_reprogram(struct hrtimer *timer, + struct hrtimer_clock_base *base) +{ + ktime_t *expires_next = &__get_cpu_var(hrtimer_bases).expires_next; + ktime_t expires = ktime_sub(timer->expires, base->offset); + int res; + + /* + * 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_interupt context. The + * reprogramming is handled either by the softirq, which called the + * callback or at the end of the hrtimer_interrupt. + */ + if (hrtimer_callback_running(timer)) + return 0; + + if (expires.tv64 >= expires_next->tv64) + return 0; + + /* + * Clockevents returns -ETIME, when the event was in the past. + */ + res = tick_program_event(expires, 0); + if (!IS_ERR_VALUE(res)) + *expires_next = expires; + return res; +} + + +/* + * Retrigger next event is called after clock was set + * + * Called with interrupts disabled via on_each_cpu() + */ +static void retrigger_next_event(void *arg) +{ + struct hrtimer_cpu_base *base; + struct timespec realtime_offset; + unsigned long seq; + + if (!hrtimer_hres_active()) + return; + + do { + seq = read_seqbegin(&xtime_lock); + set_normalized_timespec(&realtime_offset, + -wall_to_monotonic.tv_sec, + -wall_to_monotonic.tv_nsec); + } while (read_seqretry(&xtime_lock, seq)); + + base = &__get_cpu_var(hrtimer_bases); + + /* Adjust CLOCK_REALTIME offset */ + spin_lock(&base->lock); + base->clock_base[CLOCK_REALTIME].offset = + timespec_to_ktime(realtime_offset); + + hrtimer_force_reprogram(base); + spin_unlock(&base->lock); +} + +/* + * Clock realtime was set + * + * Change the offset of the realtime clock vs. the monotonic + * clock. + * + * We might have to reprogram the high resolution timer interrupt. On + * SMP we call the architecture specific code to retrigger _all_ high + * resolution timer interrupts. On UP we just disable interrupts and + * call the high resolution interrupt code. + */ +void clock_was_set(void) +{ + /* Retrigger the CPU local events everywhere */ + on_each_cpu(retrigger_next_event, NULL, 0, 1); +} + +/* + * Check, whether the timer is on the callback pending list + */ +static inline int hrtimer_cb_pending(const struct hrtimer *timer) +{ + return timer->state & HRTIMER_STATE_PENDING; +} + +/* + * Remove a timer from the callback pending list + */ +static inline void hrtimer_remove_cb_pending(struct hrtimer *timer) +{ + list_del_init(&timer->cb_entry); +} + +/* + * Initialize the high resolution related parts of cpu_base + */ +static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) +{ + base->expires_next.tv64 = KTIME_MAX; + base->hres_active = 0; + INIT_LIST_HEAD(&base->cb_pending); +} + +/* + * Initialize the high resolution related parts of a hrtimer + */ +static inline void hrtimer_init_timer_hres(struct hrtimer *timer) +{ + INIT_LIST_HEAD(&timer->cb_entry); +} + +/* + * When High resolution timers are active, try to reprogram. Note, that in case + * the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry + * check happens. The timer gets enqueued into the rbtree. The reprogramming + * and expiry check is done in the hrtimer_interrupt or in the softirq. + */ +static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, + struct hrtimer_clock_base *base) +{ + if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) { + + /* Timer is expired, act upon the callback mode */ + switch(timer->cb_mode) { + case HRTIMER_CB_IRQSAFE_NO_RESTART: + /* + * We can call the callback from here. No restart + * happens, so no danger of recursion + */ + BUG_ON(timer->function(timer) != HRTIMER_NORESTART); + return 1; + case HRTIMER_CB_IRQSAFE_NO_SOFTIRQ: + /* + * This is solely for the sched tick emulation with + * dynamic tick support to ensure that we do not + * restart the tick right on the edge and end up with + * the tick timer in the softirq ! The calling site + * takes care of this. + */ + return 1; + case HRTIMER_CB_IRQSAFE: + case HRTIMER_CB_SOFTIRQ: + /* + * Move everything else into the softirq pending list ! + */ + list_add_tail(&timer->cb_entry, + &base->cpu_base->cb_pending); + timer->state = HRTIMER_STATE_PENDING; + raise_softirq(HRTIMER_SOFTIRQ); + return 1; + default: + BUG(); + } + } + return 0; +} + +/* + * Switch to high resolution mode + */ +static void hrtimer_switch_to_hres(void) +{ + struct hrtimer_cpu_base *base = &__get_cpu_var(hrtimer_bases); + unsigned long flags; + + if (base->hres_active) + return; + + local_irq_save(flags); + + if (tick_init_highres()) { + local_irq_restore(flags); + return; + } + base->hres_active = 1; + base->clock_base[CLOCK_REALTIME].resolution = KTIME_HIGH_RES; + base->clock_base[CLOCK_MONOTONIC].resolution = KTIME_HIGH_RES; + + tick_setup_sched_timer(); + + /* "Retrigger" the interrupt to get things going */ + retrigger_next_event(NULL); + local_irq_restore(flags); + printk(KERN_INFO "Switched to high resolution mode on CPU %d\n", + smp_processor_id()); +} + +#else + +static inline int hrtimer_hres_active(void) { return 0; } +static inline int hrtimer_is_hres_enabled(void) { return 0; } +static inline void hrtimer_switch_to_hres(void) { } +static inline void hrtimer_force_reprogram(struct hrtimer_cpu_base *base) { } +static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, + struct hrtimer_clock_base *base) +{ + return 0; +} +static inline int hrtimer_cb_pending(struct hrtimer *timer) { return 0; } +static inline void hrtimer_remove_cb_pending(struct hrtimer *timer) { } +static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { } +static inline void hrtimer_init_timer_hres(struct hrtimer *timer) { } + +#endif /* CONFIG_HIGH_RES_TIMERS */ + +#ifdef CONFIG_TIMER_STATS +void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer, void *addr) +{ + if (timer->start_site) + return; + + timer->start_site = addr; + memcpy(timer->start_comm, current->comm, TASK_COMM_LEN); + timer->start_pid = current->pid; +} +#endif + /* * Counterpart to lock_timer_base above: */ static inline void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) { - spin_unlock_irqrestore(&timer->base->lock, *flags); + spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags); } /** @@ -342,7 +653,8 @@ hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval) * The timer is inserted in expiry order. Insertion into the * red black tree is O(log(n)). Must hold the base lock. */ -static void enqueue_hrtimer(struct hrtimer *timer, struct hrtimer_base *base) +static void enqueue_hrtimer(struct hrtimer *timer, + struct hrtimer_clock_base *base, int reprogram) { struct rb_node **link = &base->active.rb_node; struct rb_node *parent = NULL; @@ -368,39 +680,85 @@ static void enqueue_hrtimer(struct hrtimer *timer, struct hrtimer_base *base) * Insert the timer to the rbtree and check whether it * replaces the first pending timer */ - rb_link_node(&timer->node, parent, link); - rb_insert_color(&timer->node, &base->active); - if (!base->first || timer->expires.tv64 < - rb_entry(base->first, struct hrtimer, node)->expires.tv64) + rb_entry(base->first, struct hrtimer, node)->expires.tv64) { + /* + * Reprogram the clock event device. When the timer is already + * expired hrtimer_enqueue_reprogram has either called the + * callback or added it to the pending list and raised the + * softirq. + * + * This is a NOP for !HIGHRES + */ + if (reprogram && hrtimer_enqueue_reprogram(timer, base)) + return; + base->first = &timer->node; + } + + rb_link_node(&timer->node, parent, link); + rb_insert_color(&timer->node, &base->active); + /* + * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the + * state of a possibly running callback. + */ + timer->state |= HRTIMER_STATE_ENQUEUED; } /* * __remove_hrtimer - internal function to remove a timer * * Caller must hold the base lock. + * + * High resolution timer mode reprograms the clock event device when the + * timer is the one which expires next. The caller can disable this by setting + * reprogram to zero. This is useful, when the context does a reprogramming + * anyway (e.g. timer interrupt) */ -static void __remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base) +static void __remove_hrtimer(struct hrtimer *timer, + struct hrtimer_clock_base *base, + unsigned long newstate, int reprogram) { - /* - * Remove the timer from the rbtree and replace the - * first entry pointer if necessary. - */ - if (base->first == &timer->node) - base->first = rb_next(&timer->node); - rb_erase(&timer->node, &base->active); - rb_set_parent(&timer->node, &timer->node); + /* High res. callback list. NOP for !HIGHRES */ + if (hrtimer_cb_pending(timer)) + hrtimer_remove_cb_pending(timer); + else { + /* + * Remove the timer from the rbtree and replace the + * first entry pointer if necessary. + */ + if (base->first == &timer->node) { + base->first = rb_next(&timer->node); + /* Reprogram the clock event device. if enabled */ + if (reprogram && hrtimer_hres_active()) + hrtimer_force_reprogram(base->cpu_base); + } + rb_erase(&timer->node, &base->active); + } + timer->state = newstate; } /* * remove hrtimer, called with base lock held */ static inline int -remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base) +remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base) { - if (hrtimer_active(timer)) { - __remove_hrtimer(timer, base); + if (hrtimer_is_queued(timer)) { + int reprogram; + + /* + * Remove the timer and force reprogramming when high + * resolution mode is active and the timer is on the current + * CPU. If we remove a timer on another CPU, reprogramming is + * skipped. The interrupt event on this CPU is fired and + * reprogramming happens in the interrupt handler. This is a + * rare case and less expensive than a smp call. + */ + timer_stats_hrtimer_clear_start_info(timer); + reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases); + __remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE, + reprogram); return 1; } return 0; @@ -419,7 +777,7 @@ remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base) int hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) { - struct hrtimer_base *base, *new_base; + struct hrtimer_clock_base *base, *new_base; unsigned long flags; int ret; @@ -431,7 +789,7 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) /* Switch the timer base, if necessary: */ new_base = switch_hrtimer_base(timer, base); - if (mode == HRTIMER_REL) { + if (mode == HRTIMER_MODE_REL) { tim = ktime_add(tim, new_base->get_time()); /* * CONFIG_TIME_LOW_RES is a temporary way for architectures @@ -446,7 +804,9 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) } timer->expires = tim; - enqueue_hrtimer(timer, new_base); + timer_stats_hrtimer_set_start_info(timer); + + enqueue_hrtimer(timer, new_base, base == new_base); unlock_hrtimer_base(timer, &flags); @@ -466,13 +826,13 @@ EXPORT_SYMBOL_GPL(hrtimer_start); */ int hrtimer_try_to_cancel(struct hrtimer *timer) { - struct hrtimer_base *base; + struct hrtimer_clock_base *base; unsigned long flags; int ret = -1; base = lock_hrtimer_base(timer, &flags); - if (base->curr_timer != timer) + if (!hrtimer_callback_running(timer)) ret = remove_hrtimer(timer, base); unlock_hrtimer_base(timer, &flags); @@ -508,19 +868,19 @@ EXPORT_SYMBOL_GPL(hrtimer_cancel); */ ktime_t hrtimer_get_remaining(const struct hrtimer *timer) { - struct hrtimer_base *base; + struct hrtimer_clock_base *base; unsigned long flags; ktime_t rem; base = lock_hrtimer_base(timer, &flags); - rem = ktime_sub(timer->expires, timer->base->get_time()); + rem = ktime_sub(timer->expires, base->get_time()); unlock_hrtimer_base(timer, &flags); return rem; } EXPORT_SYMBOL_GPL(hrtimer_get_remaining); -#ifdef CONFIG_NO_IDLE_HZ +#if defined(CONFIG_NO_IDLE_HZ) || defined(CONFIG_NO_HZ) /** * hrtimer_get_next_event - get the time until next expiry event * @@ -529,26 +889,31 @@ EXPORT_SYMBOL_GPL(hrtimer_get_remaining); */ ktime_t hrtimer_get_next_event(void) { - struct hrtimer_base *base = __get_cpu_var(hrtimer_bases); + struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); + struct hrtimer_clock_base *base = cpu_base->clock_base; ktime_t delta, mindelta = { .tv64 = KTIME_MAX }; unsigned long flags; int i; - for (i = 0; i < MAX_HRTIMER_BASES; i++, base++) { - struct hrtimer *timer; + spin_lock_irqsave(&cpu_base->lock, flags); - spin_lock_irqsave(&base->lock, flags); - if (!base->first) { - spin_unlock_irqrestore(&base->lock, flags); - continue; + if (!hrtimer_hres_active()) { + for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) { + struct hrtimer *timer; + + if (!base->first) + continue; + + timer = rb_entry(base->first, struct hrtimer, node); + delta.tv64 = timer->expires.tv64; + delta = ktime_sub(delta, base->get_time()); + if (delta.tv64 < mindelta.tv64) + mindelta.tv64 = delta.tv64; } - timer = rb_entry(base->first, struct hrtimer, node); - delta.tv64 = timer->expires.tv64; - spin_unlock_irqrestore(&base->lock, flags); - delta = ktime_sub(delta, base->get_time()); - if (delta.tv64 < mindelta.tv64) - mindelta.tv64 = delta.tv64; } + + spin_unlock_irqrestore(&cpu_base->lock, flags); + if (mindelta.tv64 < 0) mindelta.tv64 = 0; return mindelta; @@ -564,17 +929,23 @@ ktime_t hrtimer_get_next_event(void) void hrtimer_init(struct hrtimer *timer, clockid_t clock_id, enum hrtimer_mode mode) { - struct hrtimer_base *bases; + struct hrtimer_cpu_base *cpu_base; memset(timer, 0, sizeof(struct hrtimer)); - bases = __raw_get_cpu_var(hrtimer_bases); + cpu_base = &__raw_get_cpu_var(hrtimer_bases); - if (clock_id == CLOCK_REALTIME && mode != HRTIMER_ABS) + if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS) clock_id = CLOCK_MONOTONIC; - timer->base = &bases[clock_id]; - rb_set_parent(&timer->node, &timer->node); + timer->base = &cpu_base->clock_base[clock_id]; + hrtimer_init_timer_hres(timer); + +#ifdef CONFIG_TIMER_STATS + timer->start_site = NULL; + timer->start_pid = -1; + memset(timer->start_comm, 0, TASK_COMM_LEN); +#endif } EXPORT_SYMBOL_GPL(hrtimer_init); @@ -583,26 +954,164 @@ EXPORT_SYMBOL_GPL(hrtimer_init); * @which_clock: which clock to query * @tp: pointer to timespec variable to store the resolution * - * Store the resolution of the clock selected by which_clock in the - * variable pointed to by tp. + * Store the resolution of the clock selected by @which_clock in the + * variable pointed to by @tp. */ int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp) { - struct hrtimer_base *bases; + struct hrtimer_cpu_base *cpu_base; - bases = __raw_get_cpu_var(hrtimer_bases); - *tp = ktime_to_timespec(bases[which_clock].resolution); + cpu_base = &__raw_get_cpu_var(hrtimer_bases); + *tp = ktime_to_timespec(cpu_base->clock_base[which_clock].resolution); return 0; } EXPORT_SYMBOL_GPL(hrtimer_get_res); +#ifdef CONFIG_HIGH_RES_TIMERS + +/* + * High resolution timer interrupt + * Called with interrupts disabled + */ +void hrtimer_interrupt(struct clock_event_device *dev) +{ + struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); + struct hrtimer_clock_base *base; + ktime_t expires_next, now; + int i, raise = 0; + + BUG_ON(!cpu_base->hres_active); + cpu_base->nr_events++; + dev->next_event.tv64 = KTIME_MAX; + + retry: + now = ktime_get(); + + expires_next.tv64 = KTIME_MAX; + + base = cpu_base->clock_base; + + for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) { + ktime_t basenow; + struct rb_node *node; + + spin_lock(&cpu_base->lock); + + basenow = ktime_add(now, base->offset); + + while ((node = base->first)) { + struct hrtimer *timer; + + timer = rb_entry(node, struct hrtimer, node); + + if (basenow.tv64 < timer->expires.tv64) { + ktime_t expires; + + expires = ktime_sub(timer->expires, + base->offset); + if (expires.tv64 < expires_next.tv64) + expires_next = expires; + break; + } + + /* Move softirq callbacks to the pending list */ + if (timer->cb_mode == HRTIMER_CB_SOFTIRQ) { + __remove_hrtimer(timer, base, + HRTIMER_STATE_PENDING, 0); + list_add_tail(&timer->cb_entry, + &base->cpu_base->cb_pending); + raise = 1; + continue; + } + + __remove_hrtimer(timer, base, + HRTIMER_STATE_CALLBACK, 0); + timer_stats_account_hrtimer(timer); + + /* + * Note: We clear the CALLBACK bit after + * enqueue_hrtimer to avoid reprogramming of + * the event hardware. This happens at the end + * of this function anyway. + */ + if (timer->function(timer) != HRTIMER_NORESTART) { + BUG_ON(timer->state != HRTIMER_STATE_CALLBACK); + enqueue_hrtimer(timer, base, 0); + } + timer->state &= ~HRTIMER_STATE_CALLBACK; + } + spin_unlock(&cpu_base->lock); + base++; + } + + cpu_base->expires_next = expires_next; + + /* Reprogramming necessary ? */ + if (expires_next.tv64 != KTIME_MAX) { + if (tick_program_event(expires_next, 0)) + goto retry; + } + + /* Raise softirq ? */ + if (raise) + raise_softirq(HRTIMER_SOFTIRQ); +} + +static void run_hrtimer_softirq(struct softirq_action *h) +{ + struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); + + spin_lock_irq(&cpu_base->lock); + + while (!list_empty(&cpu_base->cb_pending)) { + enum hrtimer_restart (*fn)(struct hrtimer *); + struct hrtimer *timer; + int restart; + + timer = list_entry(cpu_base->cb_pending.next, + struct hrtimer, cb_entry); + + timer_stats_account_hrtimer(timer); + + fn = timer->function; + __remove_hrtimer(timer, timer->base, HRTIMER_STATE_CALLBACK, 0); + spin_unlock_irq(&cpu_base->lock); + + restart = fn(timer); + + spin_lock_irq(&cpu_base->lock); + + timer->state &= ~HRTIMER_STATE_CALLBACK; + if (restart == HRTIMER_RESTART) { + BUG_ON(hrtimer_active(timer)); + /* + * Enqueue the timer, allow reprogramming of the event + * device + */ + enqueue_hrtimer(timer, timer->base, 1); + } else if (hrtimer_active(timer)) { + /* + * If the timer was rearmed on another CPU, reprogram + * the event device. + */ + if (timer->base->first == &timer->node) + hrtimer_reprogram(timer, timer->base); + } + } + spin_unlock_irq(&cpu_base->lock); +} + +#endif /* CONFIG_HIGH_RES_TIMERS */ + /* * Expire the per base hrtimer-queue: */ -static inline void run_hrtimer_queue(struct hrtimer_base *base) +static inline void run_hrtimer_queue(struct hrtimer_cpu_base *cpu_base, + int index) { struct rb_node *node; + struct hrtimer_clock_base *base = &cpu_base->clock_base[index]; if (!base->first) return; @@ -610,53 +1119,72 @@ static inline void run_hrtimer_queue(struct hrtimer_base *base) if (base->get_softirq_time) base->softirq_time = base->get_softirq_time(); - spin_lock_irq(&base->lock); + spin_lock_irq(&cpu_base->lock); while ((node = base->first)) { struct hrtimer *timer; - int (*fn)(struct hrtimer *); + enum hrtimer_restart (*fn)(struct hrtimer *); int restart; timer = rb_entry(node, struct hrtimer, node); if (base->softirq_time.tv64 <= timer->expires.tv64) break; + timer_stats_account_hrtimer(timer); + fn = timer->function; - set_curr_timer(base, timer); - __remove_hrtimer(timer, base); - spin_unlock_irq(&base->lock); + __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0); + spin_unlock_irq(&cpu_base->lock); restart = fn(timer); - spin_lock_irq(&base->lock); + spin_lock_irq(&cpu_base->lock); + timer->state &= ~HRTIMER_STATE_CALLBACK; if (restart != HRTIMER_NORESTART) { BUG_ON(hrtimer_active(timer)); - enqueue_hrtimer(timer, base); + enqueue_hrtimer(timer, base, 0); } } - set_curr_timer(base, NULL); - spin_unlock_irq(&base->lock); + spin_unlock_irq(&cpu_base->lock); } /* * Called from timer softirq every jiffy, expire hrtimers: + * + * For HRT its the fall back code to run the softirq in the timer + * softirq context in case the hrtimer initialization failed or has + * not been done yet. */ void hrtimer_run_queues(void) { - struct hrtimer_base *base = __get_cpu_var(hrtimer_bases); + struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); int i; - hrtimer_get_softirq_time(base); + if (hrtimer_hres_active()) + return; + + /* + * This _is_ ugly: We have to check in the softirq context, + * whether we can switch to highres and / or nohz mode. The + * clocksource switch happens in the timer interrupt with + * xtime_lock held. Notification from there only sets the + * check bit in the tick_oneshot code, otherwise we might + * deadlock vs. xtime_lock. + */ + if (tick_check_oneshot_change(!hrtimer_is_hres_enabled())) + hrtimer_switch_to_hres(); - for (i = 0; i < MAX_HRTIMER_BASES; i++) - run_hrtimer_queue(&base[i]); + hrtimer_get_softirq_time(cpu_base); + + for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) + run_hrtimer_queue(cpu_base, i); } /* * Sleep related functions: */ -static int hrtimer_wakeup(struct hrtimer *timer) +static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer) { struct hrtimer_sleeper *t = container_of(timer, struct hrtimer_sleeper, timer); @@ -673,6 +1201,9 @@ void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task) { sl->timer.function = hrtimer_wakeup; sl->task = task; +#ifdef CONFIG_HIGH_RES_TIMERS + sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_RESTART; +#endif } static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode) @@ -683,10 +1214,11 @@ static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mod set_current_state(TASK_INTERRUPTIBLE); hrtimer_start(&t->timer, t->timer.expires, mode); - schedule(); + if (likely(t->task)) + schedule(); hrtimer_cancel(&t->timer); - mode = HRTIMER_ABS; + mode = HRTIMER_MODE_ABS; } while (t->task && !signal_pending(current)); @@ -702,10 +1234,10 @@ long __sched hrtimer_nanosleep_restart(struct restart_block *restart) restart->fn = do_no_restart_syscall; - hrtimer_init(&t.timer, restart->arg0, HRTIMER_ABS); + hrtimer_init(&t.timer, restart->arg0, HRTIMER_MODE_ABS); t.timer.expires.tv64 = ((u64)restart->arg3 << 32) | (u64) restart->arg2; - if (do_nanosleep(&t, HRTIMER_ABS)) + if (do_nanosleep(&t, HRTIMER_MODE_ABS)) return 0; rmtp = (struct timespec __user *) restart->arg1; @@ -738,7 +1270,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp, return 0; /* Absolute timers do not update the rmtp value and restart: */ - if (mode == HRTIMER_ABS) + if (mode == HRTIMER_MODE_ABS) return -ERESTARTNOHAND; if (rmtp) { @@ -771,7 +1303,7 @@ sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp) if (!timespec_valid(&tu)) return -EINVAL; - return hrtimer_nanosleep(&tu, rmtp, HRTIMER_REL, CLOCK_MONOTONIC); + return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC); } /* @@ -779,56 +1311,60 @@ sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp) */ static void __devinit init_hrtimers_cpu(int cpu) { - struct hrtimer_base *base = per_cpu(hrtimer_bases, cpu); + struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu); int i; - for (i = 0; i < MAX_HRTIMER_BASES; i++, base++) { - spin_lock_init(&base->lock); - lockdep_set_class(&base->lock, &base->lock_key); - } + spin_lock_init(&cpu_base->lock); + lockdep_set_class(&cpu_base->lock, &cpu_base->lock_key); + + for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) + cpu_base->clock_base[i].cpu_base = cpu_base; + + hrtimer_init_hres(cpu_base); } #ifdef CONFIG_HOTPLUG_CPU -static void migrate_hrtimer_list(struct hrtimer_base *old_base, - struct hrtimer_base *new_base) +static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base, + struct hrtimer_clock_base *new_base) { struct hrtimer *timer; struct rb_node *node; while ((node = rb_first(&old_base->active))) { timer = rb_entry(node, struct hrtimer, node); - __remove_hrtimer(timer, old_base); + BUG_ON(hrtimer_callback_running(timer)); + __remove_hrtimer(timer, old_base, HRTIMER_STATE_INACTIVE, 0); timer->base = new_base; - enqueue_hrtimer(timer, new_base); + /* + * Enqueue the timer. Allow reprogramming of the event device + */ + enqueue_hrtimer(timer, new_base, 1); } } static void migrate_hrtimers(int cpu) { - struct hrtimer_base *old_base, *new_base; + struct hrtimer_cpu_base *old_base, *new_base; int i; BUG_ON(cpu_online(cpu)); - old_base = per_cpu(hrtimer_bases, cpu); - new_base = get_cpu_var(hrtimer_bases); - - local_irq_disable(); + old_base = &per_cpu(hrtimer_bases, cpu); + new_base = &get_cpu_var(hrtimer_bases); - for (i = 0; i < MAX_HRTIMER_BASES; i++) { + tick_cancel_sched_timer(cpu); - spin_lock(&new_base->lock); - spin_lock(&old_base->lock); - - BUG_ON(old_base->curr_timer); + local_irq_disable(); - migrate_hrtimer_list(old_base, new_base); + spin_lock(&new_base->lock); + spin_lock(&old_base->lock); - spin_unlock(&old_base->lock); - spin_unlock(&new_base->lock); - old_base++; - new_base++; + for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) { + migrate_hrtimer_list(&old_base->clock_base[i], + &new_base->clock_base[i]); } + spin_unlock(&old_base->lock); + spin_unlock(&new_base->lock); local_irq_enable(); put_cpu_var(hrtimer_bases); @@ -848,6 +1384,7 @@ static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self, #ifdef CONFIG_HOTPLUG_CPU case CPU_DEAD: + clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &cpu); migrate_hrtimers(cpu); break; #endif @@ -868,5 +1405,8 @@ 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, NULL); +#endif } |