hrtimer.h 4.3 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
/*
 *  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>

/*
 * Mode arguments of xxx_hrtimer functions:
 */
enum hrtimer_mode {
	HRTIMER_ABS,	/* Time value is absolute */
	HRTIMER_REL,	/* Time value is relative to now */
};

enum hrtimer_restart {
	HRTIMER_NORESTART,
	HRTIMER_RESTART,
};

37
#define HRTIMER_INACTIVE	((void *)1UL)
38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

struct hrtimer_base;

/**
 * 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.
 * @function:	timer expiry callback function
 * @base:	pointer to the timer base (per cpu and per clock)
 *
 * The hrtimer structure must be initialized by init_hrtimer_#CLOCKTYPE()
 */
struct hrtimer {
	struct rb_node		node;
	ktime_t			expires;
55
	int			(*function)(struct hrtimer *);
56 57 58
	struct hrtimer_base	*base;
};

59 60 61 62 63 64 65 66 67 68 69 70
/**
 * 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;
};

71 72
/**
 * struct hrtimer_base - the timer base for a specific clock
73 74 75 76 77 78 79
 * @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
 * @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
80
 * @get_softirq_time:	function to retrieve the current time from the softirq
81 82
 * @curr_timer:		the timer which is executing a callback right now
 * @softirq_time:	the time when running the hrtimer queue in the softirq
83
 * @lock_key:		the lock_class_key for use with lockdep
84 85 86 87 88
 */
struct hrtimer_base {
	clockid_t		index;
	spinlock_t		lock;
	struct rb_root		active;
89
	struct rb_node		*first;
90
	ktime_t			resolution;
91
	ktime_t			(*get_time)(void);
92
	ktime_t			(*get_softirq_time)(void);
93
	struct hrtimer		*curr_timer;
94
	ktime_t			softirq_time;
95
	struct lock_class_key lock_key;
96 97
};

98 99 100 101 102 103 104
/*
 * 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)

105 106 107
/* Exported timer functions: */

/* Initialize timers: */
108 109
extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
			 enum hrtimer_mode mode);
110 111 112 113 114 115 116 117 118 119 120 121 122

/* Basic timer operations: */
extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
			 const enum hrtimer_mode mode);
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)

/* 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);

123 124 125 126
#ifdef CONFIG_NO_IDLE_HZ
extern ktime_t hrtimer_get_next_event(void);
#endif

127 128
static inline int hrtimer_active(const struct hrtimer *timer)
{
129
	return rb_parent(&timer->node) != &timer->node;
130 131 132
}

/* Forward a hrtimer so it expires after now: */
133 134
extern unsigned long
hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
135

136 137 138 139 140 141
/* Precise sleep: */
extern long hrtimer_nanosleep(struct timespec *rqtp,
			      struct timespec __user *rmtp,
			      const enum hrtimer_mode mode,
			      const clockid_t clockid);

142 143 144
extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
				 struct task_struct *tsk);

145 146 147 148 149 150 151
/* Soft interrupt function to run the hrtimer queues: */
extern void hrtimer_run_queues(void);

/* Bootup initialization: */
extern void __init hrtimers_init(void);

#endif