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include/linux/hrtimer.h
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/* * 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> |
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#include <linux/percpu.h> |
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#include <linux/timer.h> |
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struct hrtimer_clock_base; struct hrtimer_cpu_base; |
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/* * Mode arguments of xxx_hrtimer functions: */ enum hrtimer_mode { |
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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, |
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}; |
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/* * Return values for the callback function */ |
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enum hrtimer_restart { |
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HRTIMER_NORESTART, /* Timer is not restarted */ HRTIMER_RESTART, /* Timer must be restarted */ |
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}; |
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/* |
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* Values to track state of the timer |
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* * Possible states: * * 0x00 inactive * 0x01 enqueued into rbtree * 0x02 callback function running |
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* |
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* Special cases: |
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* 0x03 callback function running and enqueued * (was requeued on another CPU) |
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* 0x09 timer was migrated on CPU hotunplug |
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* 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. * |
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* The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state to |
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* 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 |
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#define HRTIMER_STATE_MIGRATE 0x04 |
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/** * struct hrtimer - the basic hrtimer structure |
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* @node: red black tree node for time ordered insertion |
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* @_expires: the absolute expiry time in the hrtimers internal |
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* representation. The time is related to the clock on |
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* 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. |
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* @function: timer expiry callback function |
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* @base: pointer to the timer base (per cpu and per clock) |
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* @state: state information (See bit values above) |
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* @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 |
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* |
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* The hrtimer structure must be initialized by hrtimer_init() |
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*/ struct hrtimer { |
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struct rb_node node; |
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ktime_t _expires; |
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ktime_t _softexpires; |
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enum hrtimer_restart (*function)(struct hrtimer *); struct hrtimer_clock_base *base; |
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unsigned long state; |
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#ifdef CONFIG_TIMER_STATS |
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int start_pid; |
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void *start_site; char start_comm[16]; |
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#endif |
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}; /** |
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* struct hrtimer_sleeper - simple sleeper structure |
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* @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; }; /** |
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* struct hrtimer_clock_base - the timer base for a specific clock |
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* @cpu_base: per cpu clock base |
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* @index: clock type index for per_cpu support when moving a * timer to a base on another cpu. |
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* @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 |
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* @softirq_time: the time when running the hrtimer queue in the softirq |
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* @offset: offset of this clock to the monotonic base |
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*/ |
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struct hrtimer_clock_base { struct hrtimer_cpu_base *cpu_base; |
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clockid_t index; |
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struct rb_root active; |
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struct rb_node *first; |
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ktime_t resolution; |
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ktime_t (*get_time)(void); |
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ktime_t softirq_time; |
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#ifdef CONFIG_HIGH_RES_TIMERS ktime_t offset; |
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#endif |
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}; #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 |
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* @clock_base: array of clock bases for this cpu * @curr_timer: the timer which is executing a callback right now |
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* @expires_next: absolute time of the next event which was scheduled * via clock_set_next_event() * @hres_active: State of high resolution mode |
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* @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 |
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*/ struct hrtimer_cpu_base { |
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raw_spinlock_t lock; |
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struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; |
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#ifdef CONFIG_HIGH_RES_TIMERS ktime_t expires_next; int hres_active; |
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int hang_detected; |
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unsigned long nr_events; |
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unsigned long nr_retries; unsigned long nr_hangs; ktime_t max_hang_time; |
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#endif |
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}; |
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static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) { |
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timer->_expires = time; |
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timer->_softexpires = time; |
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} |
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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)); } |
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static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64) { |
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timer->_expires.tv64 = tv64; |
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timer->_softexpires.tv64 = tv64; |
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} static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time) { |
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timer->_expires = ktime_add_safe(timer->_expires, time); |
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timer->_softexpires = ktime_add_safe(timer->_softexpires, time); |
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} |
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static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns) |
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{ |
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timer->_expires = ktime_add_ns(timer->_expires, ns); |
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timer->_softexpires = ktime_add_ns(timer->_softexpires, ns); |
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} static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer) { |
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return timer->_expires; |
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} |
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static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer) { return timer->_softexpires; } |
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static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer) { |
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return timer->_expires.tv64; |
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} |
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static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer) { return timer->_softexpires.tv64; } |
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static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer) { |
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return ktime_to_ns(timer->_expires); |
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} static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer) { |
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return ktime_sub(timer->_expires, timer->base->get_time()); |
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} |
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#ifdef CONFIG_HIGH_RES_TIMERS struct clock_event_device; extern void clock_was_set(void); |
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extern void hres_timers_resume(void); |
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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(); } |
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static inline int hrtimer_is_hres_active(struct hrtimer *timer) { return timer->base->cpu_base->hres_active; } |
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extern void hrtimer_peek_ahead_timers(void); |
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/* * 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. */ |
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# define HIGH_RES_NSEC 1 # define KTIME_HIGH_RES (ktime_t) { .tv64 = HIGH_RES_NSEC } # define MONOTONIC_RES_NSEC HIGH_RES_NSEC |
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# define KTIME_MONOTONIC_RES KTIME_HIGH_RES #else |
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# define MONOTONIC_RES_NSEC LOW_RES_NSEC |
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# define KTIME_MONOTONIC_RES KTIME_LOW_RES |
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/* * 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. */ |
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static inline void clock_was_set(void) { } |
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static inline void hrtimer_peek_ahead_timers(void) { } |
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static inline void hres_timers_resume(void) { } |
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/* * 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; } |
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static inline int hrtimer_is_hres_active(struct hrtimer *timer) { return 0; } |
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#endif |
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extern ktime_t ktime_get(void); extern ktime_t ktime_get_real(void); |
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DECLARE_PER_CPU(struct tick_device, tick_cpu_device); |
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/* Exported timer functions: */ /* Initialize timers: */ |
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extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, enum hrtimer_mode mode); |
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#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 |
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/* Basic timer operations: */ extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode); |
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extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, unsigned long range_ns, const enum hrtimer_mode mode); |
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extern int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, unsigned long delta_ns, const enum hrtimer_mode mode, int wakeup); |
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extern int hrtimer_cancel(struct hrtimer *timer); extern int hrtimer_try_to_cancel(struct hrtimer *timer); |
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static inline int hrtimer_start_expires(struct hrtimer *timer, enum hrtimer_mode mode) { |
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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)); |
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return hrtimer_start_range_ns(timer, soft, delta, mode); |
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} |
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static inline int hrtimer_restart(struct hrtimer *timer) { |
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return hrtimer_start_expires(timer, HRTIMER_MODE_ABS); |
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} |
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/* 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); |
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extern ktime_t hrtimer_get_next_event(void); |
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/* * A timer is active, when it is enqueued into the rbtree or the callback * function is running. */ |
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static inline int hrtimer_active(const struct hrtimer *timer) { |
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return timer->state != HRTIMER_STATE_INACTIVE; |
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} |
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/* * Helper function to check, whether the timer is on one of the queues */ static inline int hrtimer_is_queued(struct hrtimer *timer) { |
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return timer->state & HRTIMER_STATE_ENQUEUED; |
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} |
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/* * 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; } |
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/* Forward a hrtimer so it expires after now: */ |
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extern u64 |
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hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); |
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/* Forward a hrtimer so it expires after the hrtimer's current now */ |
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static inline u64 hrtimer_forward_now(struct hrtimer *timer, ktime_t interval) |
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{ return hrtimer_forward(timer, timer->base->get_time(), interval); } |
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/* Precise sleep: */ extern long hrtimer_nanosleep(struct timespec *rqtp, |
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struct timespec __user *rmtp, |
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const enum hrtimer_mode mode, const clockid_t clockid); |
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extern long hrtimer_nanosleep_restart(struct restart_block *restart_block); |
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extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *tsk); |
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extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta, const enum hrtimer_mode mode); |
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extern int schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta, const enum hrtimer_mode mode, int clock); |
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extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode); |
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/* Soft interrupt function to run the hrtimer queues: */ extern void hrtimer_run_queues(void); |
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extern void hrtimer_run_pending(void); |
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/* Bootup initialization: */ extern void __init hrtimers_init(void); |
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#if BITS_PER_LONG < 64 |
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extern u64 ktime_divns(const ktime_t kt, s64 div); |
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#else /* BITS_PER_LONG < 64 */ |
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# define ktime_divns(kt, div) (u64)((kt).tv64 / (div)) |
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#endif |
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/* Show pending timers: */ extern void sysrq_timer_list_show(void); |
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#endif |