diff options
Diffstat (limited to 'include/linux/hrtimer.h')
| -rw-r--r-- | include/linux/hrtimer.h | 260 |
1 files changed, 235 insertions, 25 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index fca93025ab51..37f9279192a9 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -21,22 +21,72 @@ #include <linux/list.h> #include <linux/wait.h> +struct hrtimer_clock_base; +struct hrtimer_cpu_base; + /* * Mode arguments of xxx_hrtimer functions: */ enum hrtimer_mode { - HRTIMER_ABS, /* Time value is absolute */ - HRTIMER_REL, /* Time value is relative to now */ + HRTIMER_MODE_ABS, /* Time value is absolute */ + HRTIMER_MODE_REL, /* Time value is relative to now */ }; +/* + * Return values for the callback function + */ enum hrtimer_restart { - HRTIMER_NORESTART, - HRTIMER_RESTART, + HRTIMER_NORESTART, /* Timer is not restarted */ + HRTIMER_RESTART, /* Timer must be restarted */ }; -#define HRTIMER_INACTIVE ((void *)1UL) +/* + * hrtimer callback modes: + * + * HRTIMER_CB_SOFTIRQ: Callback must run in softirq context + * HRTIMER_CB_IRQSAFE: Callback may run in hardirq context + * HRTIMER_CB_IRQSAFE_NO_RESTART: Callback may run in hardirq context and + * does not restart the timer + * HRTIMER_CB_IRQSAFE_NO_SOFTIRQ: Callback must run in softirq context + * Special mode for tick emultation + */ +enum hrtimer_cb_mode { + HRTIMER_CB_SOFTIRQ, + HRTIMER_CB_IRQSAFE, + HRTIMER_CB_IRQSAFE_NO_RESTART, + HRTIMER_CB_IRQSAFE_NO_SOFTIRQ, +}; -struct hrtimer_base; +/* + * Values to track state of the timer + * + * Possible states: + * + * 0x00 inactive + * 0x01 enqueued into rbtree + * 0x02 callback function running + * 0x04 callback pending (high resolution mode) + * + * Special case: + * 0x03 callback function running and enqueued + * (was requeued on another CPU) + * The "callback function running and enqueued" status is only possible on + * SMP. It happens for example when a posix timer expired and the callback + * queued a signal. Between dropping the lock which protects the posix timer + * and reacquiring the base lock of the hrtimer, another CPU can deliver the + * signal and rearm the timer. We have to preserve the callback running state, + * as otherwise the timer could be removed before the softirq code finishes the + * the handling of the timer. + * + * The HRTIMER_STATE_ENQUEUE bit is always or'ed to the current state to + * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario. + * + * All state transitions are protected by cpu_base->lock. + */ +#define HRTIMER_STATE_INACTIVE 0x00 +#define HRTIMER_STATE_ENQUEUED 0x01 +#define HRTIMER_STATE_CALLBACK 0x02 +#define HRTIMER_STATE_PENDING 0x04 /** * struct hrtimer - the basic hrtimer structure @@ -46,14 +96,34 @@ struct hrtimer_base; * which the timer is based. * @function: timer expiry callback function * @base: pointer to the timer base (per cpu and per clock) + * @state: state information (See bit values above) + * @cb_mode: high resolution timer feature to select the callback execution + * mode + * @cb_entry: list head to enqueue an expired timer into the callback list + * @start_site: timer statistics field to store the site where the timer + * was started + * @start_comm: timer statistics field to store the name of the process which + * started the timer + * @start_pid: timer statistics field to store the pid of the task which + * started the timer * - * The hrtimer structure must be initialized by init_hrtimer_#CLOCKTYPE() + * The hrtimer structure must be initialized by hrtimer_init() */ struct hrtimer { - struct rb_node node; - ktime_t expires; - int (*function)(struct hrtimer *); - struct hrtimer_base *base; + struct rb_node node; + ktime_t expires; + enum hrtimer_restart (*function)(struct hrtimer *); + struct hrtimer_clock_base *base; + unsigned long state; +#ifdef CONFIG_HIGH_RES_TIMERS + enum hrtimer_cb_mode cb_mode; + struct list_head cb_entry; +#endif +#ifdef CONFIG_TIMER_STATS + void *start_site; + char start_comm[16]; + int start_pid; +#endif }; /** @@ -70,37 +140,114 @@ struct hrtimer_sleeper { /** * struct hrtimer_base - the timer base for a specific clock - * @index: clock type index for per_cpu support when moving a timer - * to a base on another cpu. - * @lock: lock protecting the base and associated timers + * @index: clock type index for per_cpu support when moving a + * timer to a base on another cpu. * @active: red black tree root node for the active timers * @first: pointer to the timer node which expires first * @resolution: the resolution of the clock, in nanoseconds * @get_time: function to retrieve the current time of the clock * @get_softirq_time: function to retrieve the current time from the softirq - * @curr_timer: the timer which is executing a callback right now * @softirq_time: the time when running the hrtimer queue in the softirq - * @lock_key: the lock_class_key for use with lockdep + * @cb_pending: list of timers where the callback is pending + * @offset: offset of this clock to the monotonic base + * @reprogram: function to reprogram the timer event */ -struct hrtimer_base { +struct hrtimer_clock_base { + struct hrtimer_cpu_base *cpu_base; clockid_t index; - spinlock_t lock; struct rb_root active; struct rb_node *first; ktime_t resolution; ktime_t (*get_time)(void); ktime_t (*get_softirq_time)(void); - struct hrtimer *curr_timer; ktime_t softirq_time; - struct lock_class_key lock_key; +#ifdef CONFIG_HIGH_RES_TIMERS + ktime_t offset; + int (*reprogram)(struct hrtimer *t, + struct hrtimer_clock_base *b, + ktime_t n); +#endif +}; + +#define HRTIMER_MAX_CLOCK_BASES 2 + +/* + * struct hrtimer_cpu_base - the per cpu clock bases + * @lock: lock protecting the base and associated clock bases + * and timers + * @lock_key: the lock_class_key for use with lockdep + * @clock_base: array of clock bases for this cpu + * @curr_timer: the timer which is executing a callback right now + * @expires_next: absolute time of the next event which was scheduled + * via clock_set_next_event() + * @hres_active: State of high resolution mode + * @check_clocks: Indictator, when set evaluate time source and clock + * event devices whether high resolution mode can be + * activated. + * @cb_pending: Expired timers are moved from the rbtree to this + * list in the timer interrupt. The list is processed + * in the softirq. + * @nr_events: Total number of timer interrupt events + */ +struct hrtimer_cpu_base { + spinlock_t lock; + struct lock_class_key lock_key; + struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; +#ifdef CONFIG_HIGH_RES_TIMERS + ktime_t expires_next; + int hres_active; + struct list_head cb_pending; + unsigned long nr_events; +#endif }; +#ifdef CONFIG_HIGH_RES_TIMERS +struct clock_event_device; + +extern void clock_was_set(void); +extern void hrtimer_interrupt(struct clock_event_device *dev); + +/* + * In high resolution mode the time reference must be read accurate + */ +static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) +{ + return timer->base->get_time(); +} + +/* + * The resolution of the clocks. The resolution value is returned in + * the clock_getres() system call to give application programmers an + * idea of the (in)accuracy of timers. Timer values are rounded up to + * this resolution values. + */ +# define KTIME_HIGH_RES (ktime_t) { .tv64 = 1 } +# define KTIME_MONOTONIC_RES KTIME_HIGH_RES + +#else + +# define KTIME_MONOTONIC_RES KTIME_LOW_RES + /* * clock_was_set() is a NOP for non- high-resolution systems. The * time-sorted order guarantees that a timer does not expire early and * is expired in the next softirq when the clock was advanced. */ -#define clock_was_set() do { } while (0) +static inline void clock_was_set(void) { } + +/* + * In non high resolution mode the time reference is taken from + * the base softirq time variable. + */ +static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) +{ + return timer->base->softirq_time; +} + +#endif + +extern ktime_t ktime_get(void); +extern ktime_t ktime_get_real(void); /* Exported timer functions: */ @@ -114,19 +261,33 @@ extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, extern int hrtimer_cancel(struct hrtimer *timer); extern int hrtimer_try_to_cancel(struct hrtimer *timer); -#define hrtimer_restart(timer) hrtimer_start((timer), (timer)->expires, HRTIMER_ABS) +static inline int hrtimer_restart(struct hrtimer *timer) +{ + return hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS); +} /* Query timers: */ extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer); extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp); -#ifdef CONFIG_NO_IDLE_HZ extern ktime_t hrtimer_get_next_event(void); -#endif +/* + * A timer is active, when it is enqueued into the rbtree or the callback + * function is running. + */ static inline int hrtimer_active(const struct hrtimer *timer) { - return rb_parent(&timer->node) != &timer->node; + return timer->state != HRTIMER_STATE_INACTIVE; +} + +/* + * Helper function to check, whether the timer is on one of the queues + */ +static inline int hrtimer_is_queued(struct hrtimer *timer) +{ + return timer->state & + (HRTIMER_STATE_ENQUEUED | HRTIMER_STATE_PENDING); } /* Forward a hrtimer so it expires after now: */ @@ -149,4 +310,53 @@ extern void hrtimer_run_queues(void); /* Bootup initialization: */ extern void __init hrtimers_init(void); +#if BITS_PER_LONG < 64 +extern unsigned long ktime_divns(const ktime_t kt, s64 div); +#else /* BITS_PER_LONG < 64 */ +# define ktime_divns(kt, div) (unsigned long)((kt).tv64 / (div)) +#endif + +/* Show pending timers: */ +extern void sysrq_timer_list_show(void); + +/* + * Timer-statistics info: + */ +#ifdef CONFIG_TIMER_STATS + +extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf, + void *timerf, char * comm); + +static inline void timer_stats_account_hrtimer(struct hrtimer *timer) +{ + timer_stats_update_stats(timer, timer->start_pid, timer->start_site, + timer->function, timer->start_comm); +} + +extern void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer, + void *addr); + +static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer) +{ + __timer_stats_hrtimer_set_start_info(timer, __builtin_return_address(0)); +} + +static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer) +{ + timer->start_site = NULL; +} +#else +static inline void timer_stats_account_hrtimer(struct hrtimer *timer) +{ +} + +static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer) +{ +} + +static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer) +{ +} +#endif + #endif |