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Diffstat (limited to 'include/linux/hrtimer.h')
| -rw-r--r-- | include/linux/hrtimer.h | 453 |
1 files changed, 453 insertions, 0 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h new file mode 100644 index 00000000..fd0dc30c --- /dev/null +++ b/include/linux/hrtimer.h @@ -0,0 +1,453 @@ +/* + * include/linux/hrtimer.h + * + * hrtimers - High-resolution kernel timers + * + * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de> + * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar + * + * data type definitions, declarations, prototypes + * + * Started by: Thomas Gleixner and Ingo Molnar + * + * For licencing details see kernel-base/COPYING + */ +#ifndef _LINUX_HRTIMER_H +#define _LINUX_HRTIMER_H + +#include <linux/rbtree.h> +#include <linux/ktime.h> +#include <linux/init.h> +#include <linux/list.h> +#include <linux/wait.h> +#include <linux/percpu.h> +#include <linux/timer.h> +#include <linux/timerqueue.h> + +struct hrtimer_clock_base; +struct hrtimer_cpu_base; + +/* + * Mode arguments of xxx_hrtimer functions: + */ +enum hrtimer_mode { + HRTIMER_MODE_ABS = 0x0, /* Time value is absolute */ + HRTIMER_MODE_REL = 0x1, /* Time value is relative to now */ + HRTIMER_MODE_PINNED = 0x02, /* Timer is bound to CPU */ + HRTIMER_MODE_ABS_PINNED = 0x02, + HRTIMER_MODE_REL_PINNED = 0x03, +}; + +/* + * Return values for the callback function + */ +enum hrtimer_restart { + HRTIMER_NORESTART, /* Timer is not restarted */ + HRTIMER_RESTART, /* Timer must be restarted */ +}; + +/* + * Values to track state of the timer + * + * Possible states: + * + * 0x00 inactive + * 0x01 enqueued into rbtree + * 0x02 callback function running + * 0x04 timer is migrated to another cpu + * + * Special cases: + * 0x03 callback function running and enqueued + * (was requeued on another CPU) + * 0x05 timer was migrated on CPU hotunplug + * + * 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_ENQUEUED bit is always or'ed to the current state + * to preserve the HRTIMER_STATE_CALLBACK in the above scenario. This + * also affects HRTIMER_STATE_MIGRATE where the preservation is not + * necessary. HRTIMER_STATE_MIGRATE is cleared after the timer is + * enqueued on the new cpu. + * + * 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_MIGRATE 0x04 + +/** + * struct hrtimer - the basic hrtimer structure + * @node: timerqueue node, which also manages node.expires, + * the absolute expiry time in the hrtimers internal + * representation. The time is related to the clock on + * which the timer is based. Is setup by adding + * slack to the _softexpires value. For non range timers + * identical to _softexpires. + * @_softexpires: the absolute earliest expiry time of the hrtimer. + * The time which was given as expiry time when the timer + * was armed. + * @function: timer expiry callback function + * @base: pointer to the timer base (per cpu and per clock) + * @state: state information (See bit values above) + * @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 hrtimer_init() + */ +struct hrtimer { + struct timerqueue_node node; + ktime_t _softexpires; + enum hrtimer_restart (*function)(struct hrtimer *); + struct hrtimer_clock_base *base; + unsigned long state; +#ifdef CONFIG_TIMER_STATS + int start_pid; + void *start_site; + char start_comm[16]; +#endif +}; + +/** + * struct hrtimer_sleeper - simple sleeper structure + * @timer: embedded timer structure + * @task: task to wake up + * + * task is set to NULL, when the timer expires. + */ +struct hrtimer_sleeper { + struct hrtimer timer; + struct task_struct *task; +}; + +/** + * struct hrtimer_clock_base - the timer base for a specific clock + * @cpu_base: per cpu clock base + * @index: clock type index for per_cpu support when moving a + * timer to a base on another cpu. + * @clockid: clock id for per_cpu support + * @active: red black tree root node for the active timers + * @resolution: the resolution of the clock, in nanoseconds + * @get_time: function to retrieve the current time of the clock + * @softirq_time: the time when running the hrtimer queue in the softirq + * @offset: offset of this clock to the monotonic base + */ +struct hrtimer_clock_base { + struct hrtimer_cpu_base *cpu_base; + int index; + clockid_t clockid; + struct timerqueue_head active; + ktime_t resolution; + ktime_t (*get_time)(void); + ktime_t softirq_time; + ktime_t offset; +}; + +enum hrtimer_base_type { + HRTIMER_BASE_MONOTONIC, + HRTIMER_BASE_REALTIME, + HRTIMER_BASE_BOOTTIME, + HRTIMER_MAX_CLOCK_BASES, +}; + +/* + * struct hrtimer_cpu_base - the per cpu clock bases + * @lock: lock protecting the base and associated clock bases + * and timers + * @active_bases: Bitfield to mark bases with active timers + * @expires_next: absolute time of the next event which was scheduled + * via clock_set_next_event() + * @hres_active: State of high resolution mode + * @hang_detected: The last hrtimer interrupt detected a hang + * @nr_events: Total number of hrtimer interrupt events + * @nr_retries: Total number of hrtimer interrupt retries + * @nr_hangs: Total number of hrtimer interrupt hangs + * @max_hang_time: Maximum time spent in hrtimer_interrupt + * @clock_base: array of clock bases for this cpu + */ +struct hrtimer_cpu_base { + raw_spinlock_t lock; + unsigned long active_bases; +#ifdef CONFIG_HIGH_RES_TIMERS + ktime_t expires_next; + int hres_active; + int hang_detected; + unsigned long nr_events; + unsigned long nr_retries; + unsigned long nr_hangs; + ktime_t max_hang_time; +#endif + struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; +}; + +static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) +{ + timer->node.expires = time; + timer->_softexpires = time; +} + +static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta) +{ + timer->_softexpires = time; + timer->node.expires = ktime_add_safe(time, delta); +} + +static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta) +{ + timer->_softexpires = time; + timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta)); +} + +static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64) +{ + timer->node.expires.tv64 = tv64; + timer->_softexpires.tv64 = tv64; +} + +static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time) +{ + timer->node.expires = ktime_add_safe(timer->node.expires, time); + timer->_softexpires = ktime_add_safe(timer->_softexpires, time); +} + +static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns) +{ + timer->node.expires = ktime_add_ns(timer->node.expires, ns); + timer->_softexpires = ktime_add_ns(timer->_softexpires, ns); +} + +static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer) +{ + return timer->node.expires; +} + +static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer) +{ + return timer->_softexpires; +} + +static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer) +{ + return timer->node.expires.tv64; +} +static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer) +{ + return timer->_softexpires.tv64; +} + +static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer) +{ + return ktime_to_ns(timer->node.expires); +} + +static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer) +{ + return ktime_sub(timer->node.expires, timer->base->get_time()); +} + +#ifdef CONFIG_HIGH_RES_TIMERS +struct clock_event_device; + +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(); +} + +static inline int hrtimer_is_hres_active(struct hrtimer *timer) +{ + return timer->base->cpu_base->hres_active; +} + +extern void hrtimer_peek_ahead_timers(void); + +/* + * 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 HIGH_RES_NSEC 1 +# define KTIME_HIGH_RES (ktime_t) { .tv64 = HIGH_RES_NSEC } +# define MONOTONIC_RES_NSEC HIGH_RES_NSEC +# define KTIME_MONOTONIC_RES KTIME_HIGH_RES + +#else + +# define MONOTONIC_RES_NSEC LOW_RES_NSEC +# define KTIME_MONOTONIC_RES KTIME_LOW_RES + +static inline void hrtimer_peek_ahead_timers(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; +} + +static inline int hrtimer_is_hres_active(struct hrtimer *timer) +{ + return 0; +} +#endif + +extern void clock_was_set(void); +#ifdef CONFIG_TIMERFD +extern void timerfd_clock_was_set(void); +#else +static inline void timerfd_clock_was_set(void) { } +#endif +extern void hrtimers_resume(void); + +extern ktime_t ktime_get(void); +extern ktime_t ktime_get_real(void); +extern ktime_t ktime_get_boottime(void); +extern ktime_t ktime_get_monotonic_offset(void); + +DECLARE_PER_CPU(struct tick_device, tick_cpu_device); + + +/* Exported timer functions: */ + +/* Initialize timers: */ +extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, + enum hrtimer_mode mode); + +#ifdef CONFIG_DEBUG_OBJECTS_TIMERS +extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock, + enum hrtimer_mode mode); + +extern void destroy_hrtimer_on_stack(struct hrtimer *timer); +#else +static inline void hrtimer_init_on_stack(struct hrtimer *timer, + clockid_t which_clock, + enum hrtimer_mode mode) +{ + hrtimer_init(timer, which_clock, mode); +} +static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { } +#endif + +/* Basic timer operations: */ +extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, + const enum hrtimer_mode mode); +extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, + unsigned long range_ns, const enum hrtimer_mode mode); +extern int +__hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, + unsigned long delta_ns, + const enum hrtimer_mode mode, int wakeup); + +extern int hrtimer_cancel(struct hrtimer *timer); +extern int hrtimer_try_to_cancel(struct hrtimer *timer); + +static inline int hrtimer_start_expires(struct hrtimer *timer, + enum hrtimer_mode mode) +{ + unsigned long delta; + ktime_t soft, hard; + soft = hrtimer_get_softexpires(timer); + hard = hrtimer_get_expires(timer); + delta = ktime_to_ns(ktime_sub(hard, soft)); + return hrtimer_start_range_ns(timer, soft, delta, mode); +} + +static inline int hrtimer_restart(struct hrtimer *timer) +{ + return hrtimer_start_expires(timer, 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); + +extern ktime_t hrtimer_get_next_event(void); + +/* + * A timer is active, when it is enqueued into the rbtree or the + * callback function is running or it's in the state of being migrated + * to another cpu. + */ +static inline int hrtimer_active(const struct hrtimer *timer) +{ + 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; +} + +/* + * 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; +} + +/* Forward a hrtimer so it expires after now: */ +extern u64 +hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); + +/* Forward a hrtimer so it expires after the hrtimer's current now */ +static inline u64 hrtimer_forward_now(struct hrtimer *timer, + ktime_t interval) +{ + return hrtimer_forward(timer, timer->base->get_time(), interval); +} + +/* Precise sleep: */ +extern long hrtimer_nanosleep(struct timespec *rqtp, + struct timespec __user *rmtp, + const enum hrtimer_mode mode, + const clockid_t clockid); +extern long hrtimer_nanosleep_restart(struct restart_block *restart_block); + +extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, + struct task_struct *tsk); + +extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta, + const enum hrtimer_mode mode); +extern int schedule_hrtimeout_range_clock(ktime_t *expires, + unsigned long delta, const enum hrtimer_mode mode, int clock); +extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode); + +/* Soft interrupt function to run the hrtimer queues: */ +extern void hrtimer_run_queues(void); +extern void hrtimer_run_pending(void); + +/* Bootup initialization: */ +extern void __init hrtimers_init(void); + +#if BITS_PER_LONG < 64 +extern u64 ktime_divns(const ktime_t kt, s64 div); +#else /* BITS_PER_LONG < 64 */ +# define ktime_divns(kt, div) (u64)((kt).tv64 / (div)) +#endif + +/* Show pending timers: */ +extern void sysrq_timer_list_show(void); + +#endif |