2 * include/linux/hrtimer.h
4 * hrtimers - High-resolution kernel timers
6 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
7 * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
9 * data type definitions, declarations, prototypes
11 * Started by: Thomas Gleixner and Ingo Molnar
13 * For licencing details see kernel-base/COPYING
15 #ifndef _LINUX_HRTIMER_H
16 #define _LINUX_HRTIMER_H
18 #include <linux/rbtree.h>
19 #include <linux/ktime.h>
20 #include <linux/init.h>
21 #include <linux/list.h>
22 #include <linux/wait.h>
23 #include <linux/percpu.h>
26 struct hrtimer_clock_base
;
27 struct hrtimer_cpu_base
;
30 * Mode arguments of xxx_hrtimer functions:
33 HRTIMER_MODE_ABS
= 0x0, /* Time value is absolute */
34 HRTIMER_MODE_REL
= 0x1, /* Time value is relative to now */
35 HRTIMER_MODE_PINNED
= 0x02, /* Timer is bound to CPU */
36 HRTIMER_MODE_ABS_PINNED
= 0x02,
37 HRTIMER_MODE_REL_PINNED
= 0x03,
41 * Return values for the callback function
43 enum hrtimer_restart
{
44 HRTIMER_NORESTART
, /* Timer is not restarted */
45 HRTIMER_RESTART
, /* Timer must be restarted */
49 * Values to track state of the timer
54 * 0x01 enqueued into rbtree
55 * 0x02 callback function running
58 * 0x03 callback function running and enqueued
59 * (was requeued on another CPU)
60 * 0x09 timer was migrated on CPU hotunplug
61 * The "callback function running and enqueued" status is only possible on
62 * SMP. It happens for example when a posix timer expired and the callback
63 * queued a signal. Between dropping the lock which protects the posix timer
64 * and reacquiring the base lock of the hrtimer, another CPU can deliver the
65 * signal and rearm the timer. We have to preserve the callback running state,
66 * as otherwise the timer could be removed before the softirq code finishes the
67 * the handling of the timer.
69 * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state to
70 * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario.
72 * All state transitions are protected by cpu_base->lock.
74 #define HRTIMER_STATE_INACTIVE 0x00
75 #define HRTIMER_STATE_ENQUEUED 0x01
76 #define HRTIMER_STATE_CALLBACK 0x02
77 #define HRTIMER_STATE_MIGRATE 0x04
80 * struct hrtimer - the basic hrtimer structure
81 * @node: red black tree node for time ordered insertion
82 * @_expires: the absolute expiry time in the hrtimers internal
83 * representation. The time is related to the clock on
84 * which the timer is based. Is setup by adding
85 * slack to the _softexpires value. For non range timers
86 * identical to _softexpires.
87 * @_softexpires: the absolute earliest expiry time of the hrtimer.
88 * The time which was given as expiry time when the timer
90 * @function: timer expiry callback function
91 * @base: pointer to the timer base (per cpu and per clock)
92 * @state: state information (See bit values above)
93 * @cb_entry: list head to enqueue an expired timer into the callback list
94 * @start_site: timer statistics field to store the site where the timer
96 * @start_comm: timer statistics field to store the name of the process which
98 * @start_pid: timer statistics field to store the pid of the task which
101 * The hrtimer structure must be initialized by hrtimer_init()
106 ktime_t _softexpires
;
107 enum hrtimer_restart (*function
)(struct hrtimer
*);
108 struct hrtimer_clock_base
*base
;
110 struct list_head cb_entry
;
111 #ifdef CONFIG_TIMER_STATS
119 * struct hrtimer_sleeper - simple sleeper structure
120 * @timer: embedded timer structure
121 * @task: task to wake up
123 * task is set to NULL, when the timer expires.
125 struct hrtimer_sleeper
{
126 struct hrtimer timer
;
127 struct task_struct
*task
;
131 * struct hrtimer_clock_base - the timer base for a specific clock
132 * @cpu_base: per cpu clock base
133 * @index: clock type index for per_cpu support when moving a
134 * timer to a base on another cpu.
135 * @active: red black tree root node for the active timers
136 * @first: pointer to the timer node which expires first
137 * @resolution: the resolution of the clock, in nanoseconds
138 * @get_time: function to retrieve the current time of the clock
139 * @softirq_time: the time when running the hrtimer queue in the softirq
140 * @offset: offset of this clock to the monotonic base
142 struct hrtimer_clock_base
{
143 struct hrtimer_cpu_base
*cpu_base
;
145 struct rb_root active
;
146 struct rb_node
*first
;
148 ktime_t (*get_time
)(void);
149 ktime_t softirq_time
;
150 #ifdef CONFIG_HIGH_RES_TIMERS
155 #define HRTIMER_MAX_CLOCK_BASES 2
158 * struct hrtimer_cpu_base - the per cpu clock bases
159 * @lock: lock protecting the base and associated clock bases
161 * @clock_base: array of clock bases for this cpu
162 * @curr_timer: the timer which is executing a callback right now
163 * @expires_next: absolute time of the next event which was scheduled
164 * via clock_set_next_event()
165 * @hres_active: State of high resolution mode
166 * @check_clocks: Indictator, when set evaluate time source and clock
167 * event devices whether high resolution mode can be
169 * @nr_events: Total number of timer interrupt events
171 struct hrtimer_cpu_base
{
173 struct hrtimer_clock_base clock_base
[HRTIMER_MAX_CLOCK_BASES
];
174 #ifdef CONFIG_HIGH_RES_TIMERS
175 ktime_t expires_next
;
177 unsigned long nr_events
;
181 static inline void hrtimer_set_expires(struct hrtimer
*timer
, ktime_t time
)
183 timer
->_expires
= time
;
184 timer
->_softexpires
= time
;
187 static inline void hrtimer_set_expires_range(struct hrtimer
*timer
, ktime_t time
, ktime_t delta
)
189 timer
->_softexpires
= time
;
190 timer
->_expires
= ktime_add_safe(time
, delta
);
193 static inline void hrtimer_set_expires_range_ns(struct hrtimer
*timer
, ktime_t time
, unsigned long delta
)
195 timer
->_softexpires
= time
;
196 timer
->_expires
= ktime_add_safe(time
, ns_to_ktime(delta
));
199 static inline void hrtimer_set_expires_tv64(struct hrtimer
*timer
, s64 tv64
)
201 timer
->_expires
.tv64
= tv64
;
202 timer
->_softexpires
.tv64
= tv64
;
205 static inline void hrtimer_add_expires(struct hrtimer
*timer
, ktime_t time
)
207 timer
->_expires
= ktime_add_safe(timer
->_expires
, time
);
208 timer
->_softexpires
= ktime_add_safe(timer
->_softexpires
, time
);
211 static inline void hrtimer_add_expires_ns(struct hrtimer
*timer
, u64 ns
)
213 timer
->_expires
= ktime_add_ns(timer
->_expires
, ns
);
214 timer
->_softexpires
= ktime_add_ns(timer
->_softexpires
, ns
);
217 static inline ktime_t
hrtimer_get_expires(const struct hrtimer
*timer
)
219 return timer
->_expires
;
222 static inline ktime_t
hrtimer_get_softexpires(const struct hrtimer
*timer
)
224 return timer
->_softexpires
;
227 static inline s64
hrtimer_get_expires_tv64(const struct hrtimer
*timer
)
229 return timer
->_expires
.tv64
;
231 static inline s64
hrtimer_get_softexpires_tv64(const struct hrtimer
*timer
)
233 return timer
->_softexpires
.tv64
;
236 static inline s64
hrtimer_get_expires_ns(const struct hrtimer
*timer
)
238 return ktime_to_ns(timer
->_expires
);
241 static inline ktime_t
hrtimer_expires_remaining(const struct hrtimer
*timer
)
243 return ktime_sub(timer
->_expires
, timer
->base
->get_time());
246 #ifdef CONFIG_HIGH_RES_TIMERS
247 struct clock_event_device
;
249 extern void clock_was_set(void);
250 extern void hres_timers_resume(void);
251 extern void hrtimer_interrupt(struct clock_event_device
*dev
);
254 * In high resolution mode the time reference must be read accurate
256 static inline ktime_t
hrtimer_cb_get_time(struct hrtimer
*timer
)
258 return timer
->base
->get_time();
261 static inline int hrtimer_is_hres_active(struct hrtimer
*timer
)
263 return timer
->base
->cpu_base
->hres_active
;
266 extern void hrtimer_peek_ahead_timers(void);
269 * The resolution of the clocks. The resolution value is returned in
270 * the clock_getres() system call to give application programmers an
271 * idea of the (in)accuracy of timers. Timer values are rounded up to
272 * this resolution values.
274 # define HIGH_RES_NSEC 1
275 # define KTIME_HIGH_RES (ktime_t) { .tv64 = HIGH_RES_NSEC }
276 # define MONOTONIC_RES_NSEC HIGH_RES_NSEC
277 # define KTIME_MONOTONIC_RES KTIME_HIGH_RES
281 # define MONOTONIC_RES_NSEC LOW_RES_NSEC
282 # define KTIME_MONOTONIC_RES KTIME_LOW_RES
285 * clock_was_set() is a NOP for non- high-resolution systems. The
286 * time-sorted order guarantees that a timer does not expire early and
287 * is expired in the next softirq when the clock was advanced.
289 static inline void clock_was_set(void) { }
290 static inline void hrtimer_peek_ahead_timers(void) { }
292 static inline void hres_timers_resume(void) { }
295 * In non high resolution mode the time reference is taken from
296 * the base softirq time variable.
298 static inline ktime_t
hrtimer_cb_get_time(struct hrtimer
*timer
)
300 return timer
->base
->softirq_time
;
303 static inline int hrtimer_is_hres_active(struct hrtimer
*timer
)
309 extern ktime_t
ktime_get(void);
310 extern ktime_t
ktime_get_real(void);
313 DECLARE_PER_CPU(struct tick_device
, tick_cpu_device
);
316 /* Exported timer functions: */
318 /* Initialize timers: */
319 extern void hrtimer_init(struct hrtimer
*timer
, clockid_t which_clock
,
320 enum hrtimer_mode mode
);
322 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
323 extern void hrtimer_init_on_stack(struct hrtimer
*timer
, clockid_t which_clock
,
324 enum hrtimer_mode mode
);
326 extern void destroy_hrtimer_on_stack(struct hrtimer
*timer
);
328 static inline void hrtimer_init_on_stack(struct hrtimer
*timer
,
329 clockid_t which_clock
,
330 enum hrtimer_mode mode
)
332 hrtimer_init(timer
, which_clock
, mode
);
334 static inline void destroy_hrtimer_on_stack(struct hrtimer
*timer
) { }
337 /* Basic timer operations: */
338 extern int hrtimer_start(struct hrtimer
*timer
, ktime_t tim
,
339 const enum hrtimer_mode mode
);
340 extern int hrtimer_start_range_ns(struct hrtimer
*timer
, ktime_t tim
,
341 unsigned long range_ns
, const enum hrtimer_mode mode
);
343 __hrtimer_start_range_ns(struct hrtimer
*timer
, ktime_t tim
,
344 unsigned long delta_ns
,
345 const enum hrtimer_mode mode
, int wakeup
);
347 extern int hrtimer_cancel(struct hrtimer
*timer
);
348 extern int hrtimer_try_to_cancel(struct hrtimer
*timer
);
350 static inline int hrtimer_start_expires(struct hrtimer
*timer
,
351 enum hrtimer_mode mode
)
355 soft
= hrtimer_get_softexpires(timer
);
356 hard
= hrtimer_get_expires(timer
);
357 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
358 return hrtimer_start_range_ns(timer
, soft
, delta
, mode
);
361 static inline int hrtimer_restart(struct hrtimer
*timer
)
363 return hrtimer_start_expires(timer
, HRTIMER_MODE_ABS
);
367 extern ktime_t
hrtimer_get_remaining(const struct hrtimer
*timer
);
368 extern int hrtimer_get_res(const clockid_t which_clock
, struct timespec
*tp
);
370 extern ktime_t
hrtimer_get_next_event(void);
373 * A timer is active, when it is enqueued into the rbtree or the callback
374 * function is running.
376 static inline int hrtimer_active(const struct hrtimer
*timer
)
378 return timer
->state
!= HRTIMER_STATE_INACTIVE
;
382 * Helper function to check, whether the timer is on one of the queues
384 static inline int hrtimer_is_queued(struct hrtimer
*timer
)
386 return timer
->state
& HRTIMER_STATE_ENQUEUED
;
390 * Helper function to check, whether the timer is running the callback
393 static inline int hrtimer_callback_running(struct hrtimer
*timer
)
395 return timer
->state
& HRTIMER_STATE_CALLBACK
;
398 /* Forward a hrtimer so it expires after now: */
400 hrtimer_forward(struct hrtimer
*timer
, ktime_t now
, ktime_t interval
);
402 /* Forward a hrtimer so it expires after the hrtimer's current now */
403 static inline u64
hrtimer_forward_now(struct hrtimer
*timer
,
406 return hrtimer_forward(timer
, timer
->base
->get_time(), interval
);
410 extern long hrtimer_nanosleep(struct timespec
*rqtp
,
411 struct timespec __user
*rmtp
,
412 const enum hrtimer_mode mode
,
413 const clockid_t clockid
);
414 extern long hrtimer_nanosleep_restart(struct restart_block
*restart_block
);
416 extern void hrtimer_init_sleeper(struct hrtimer_sleeper
*sl
,
417 struct task_struct
*tsk
);
419 extern int schedule_hrtimeout_range(ktime_t
*expires
, unsigned long delta
,
420 const enum hrtimer_mode mode
);
421 extern int schedule_hrtimeout(ktime_t
*expires
, const enum hrtimer_mode mode
);
423 /* Soft interrupt function to run the hrtimer queues: */
424 extern void hrtimer_run_queues(void);
425 extern void hrtimer_run_pending(void);
427 /* Bootup initialization: */
428 extern void __init
hrtimers_init(void);
430 #if BITS_PER_LONG < 64
431 extern u64
ktime_divns(const ktime_t kt
, s64 div
);
432 #else /* BITS_PER_LONG < 64 */
433 # define ktime_divns(kt, div) (u64)((kt).tv64 / (div))
436 /* Show pending timers: */
437 extern void sysrq_timer_list_show(void);
440 * Timer-statistics info:
442 #ifdef CONFIG_TIMER_STATS
444 extern void timer_stats_update_stats(void *timer
, pid_t pid
, void *startf
,
445 void *timerf
, char *comm
,
446 unsigned int timer_flag
);
448 static inline void timer_stats_account_hrtimer(struct hrtimer
*timer
)
450 timer_stats_update_stats(timer
, timer
->start_pid
, timer
->start_site
,
451 timer
->function
, timer
->start_comm
, 0);
454 extern void __timer_stats_hrtimer_set_start_info(struct hrtimer
*timer
,
457 static inline void timer_stats_hrtimer_set_start_info(struct hrtimer
*timer
)
459 __timer_stats_hrtimer_set_start_info(timer
, __builtin_return_address(0));
462 static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer
*timer
)
464 timer
->start_site
= NULL
;
467 static inline void timer_stats_account_hrtimer(struct hrtimer
*timer
)
471 static inline void timer_stats_hrtimer_set_start_info(struct hrtimer
*timer
)
475 static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer
*timer
)