/* * 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> struct hrtimer_clock_base; struct hrtimer_cpu_base; /* * Mode arguments of xxx_hrtimer functions: */ enum hrtimer_mode { 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, /* 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 * * Special cases: * 0x03 callback function running and enqueued * (was requeued on another CPU) * 0x09 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 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_MIGRATE 0x04 /** * struct hrtimer - the basic hrtimer structure * @node: red black tree node for time ordered insertion * @_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) * @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 hrtimer_init() */ struct hrtimer { struct rb_node node; ktime_t _expires; ktime_t _softexpires; enum hrtimer_restart (*function)(struct hrtimer *); struct hrtimer_clock_base *base; unsigned long state; struct list_head cb_entry; #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. * @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 * @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; clockid_t index; struct rb_root active; struct rb_node *first; ktime_t resolution; ktime_t (*get_time)(void); ktime_t softirq_time; #ifdef CONFIG_HIGH_RES_TIMERS ktime_t offset; #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 * @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. * @nr_events: Total number of timer interrupt events */ struct hrtimer_cpu_base { spinlock_t lock; struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; #ifdef CONFIG_HIGH_RES_TIMERS ktime_t expires_next; int hres_active; unsigned long nr_events; #endif }; static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) { timer->_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->_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->_expires = ktime_add_safe(time, ns_to_ktime(delta)); } static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64) { timer->_expires.tv64 = tv64; timer->_softexpires.tv64 = tv64; } static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time) { timer->_expires = ktime_add_safe(timer->_expires, time); timer->_softexpires = ktime_add_safe(timer->_softexpires, time); } static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns) { timer->_expires = ktime_add_ns(timer->_expires, ns); timer->_softexpires = ktime_add_ns(timer->_softexpires, ns); } static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer) { return timer->_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->_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->_expires); } static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer) { return ktime_sub(timer->_expires, timer->base->get_time()); } #ifdef CONFIG_HIGH_RES_TIMERS struct clock_event_device; extern void clock_was_set(void); extern void hres_timers_resume(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(); } 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 /* * 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. */ static inline void clock_was_set(void) { } static inline void hrtimer_peek_ahead_timers(void) { } static inline void hres_timers_resume(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 ktime_t ktime_get(void); extern ktime_t ktime_get_real(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_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. */ 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(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); /* * Timer-statistics info: */ #ifdef CONFIG_TIMER_STATS extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf, void *timerf, char *comm, unsigned int timer_flag); 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, 0); } 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