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>
24 #include <linux/timer.h>
27 struct hrtimer_clock_base;
28 struct hrtimer_cpu_base;
31 * Mode arguments of xxx_hrtimer functions:
34 HRTIMER_MODE_ABS = 0x0, /* Time value is absolute */
35 HRTIMER_MODE_REL = 0x1, /* Time value is relative to now */
36 HRTIMER_MODE_PINNED = 0x02, /* Timer is bound to CPU */
37 HRTIMER_MODE_ABS_PINNED = 0x02,
38 HRTIMER_MODE_REL_PINNED = 0x03,
42 * Return values for the callback function
44 enum hrtimer_restart {
45 HRTIMER_NORESTART, /* Timer is not restarted */
46 HRTIMER_RESTART, /* Timer must be restarted */
50 * Values to track state of the timer
55 * 0x01 enqueued into rbtree
56 * 0x02 callback function running
59 * 0x03 callback function running and enqueued
60 * (was requeued on another CPU)
61 * 0x09 timer was migrated on CPU hotunplug
62 * The "callback function running and enqueued" status is only possible on
63 * SMP. It happens for example when a posix timer expired and the callback
64 * queued a signal. Between dropping the lock which protects the posix timer
65 * and reacquiring the base lock of the hrtimer, another CPU can deliver the
66 * signal and rearm the timer. We have to preserve the callback running state,
67 * as otherwise the timer could be removed before the softirq code finishes the
68 * the handling of the timer.
70 * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state to
71 * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario.
73 * All state transitions are protected by cpu_base->lock.
75 #define HRTIMER_STATE_INACTIVE 0x00
76 #define HRTIMER_STATE_ENQUEUED 0x01
77 #define HRTIMER_STATE_CALLBACK 0x02
78 #define HRTIMER_STATE_MIGRATE 0x04
81 * struct hrtimer - the basic hrtimer structure
82 * @node: red black tree node for time ordered insertion
83 * @_expires: the absolute expiry time in the hrtimers internal
84 * representation. The time is related to the clock on
85 * which the timer is based. Is setup by adding
86 * slack to the _softexpires value. For non range timers
87 * identical to _softexpires.
88 * @_softexpires: the absolute earliest expiry time of the hrtimer.
89 * The time which was given as expiry time when the timer
91 * @function: timer expiry callback function
92 * @base: pointer to the timer base (per cpu and per clock)
93 * @state: state information (See bit values above)
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 #ifdef CONFIG_TIMER_STATS
118 * struct hrtimer_sleeper - simple sleeper structure
119 * @timer: embedded timer structure
120 * @task: task to wake up
122 * task is set to NULL, when the timer expires.
124 struct hrtimer_sleeper {
125 struct hrtimer timer;
126 struct task_struct *task;
130 * struct hrtimer_clock_base - the timer base for a specific clock
131 * @cpu_base: per cpu clock base
132 * @index: clock type index for per_cpu support when moving a
133 * timer to a base on another cpu.
134 * @active: red black tree root node for the active timers
135 * @first: pointer to the timer node which expires first
136 * @resolution: the resolution of the clock, in nanoseconds
137 * @get_time: function to retrieve the current time of the clock
138 * @softirq_time: the time when running the hrtimer queue in the softirq
139 * @offset: offset of this clock to the monotonic base
141 struct hrtimer_clock_base {
142 struct hrtimer_cpu_base *cpu_base;
144 struct rb_root active;
145 struct rb_node *first;
147 ktime_t (*get_time)(void);
148 ktime_t softirq_time;
149 #ifdef CONFIG_HIGH_RES_TIMERS
154 #define HRTIMER_MAX_CLOCK_BASES 2
157 * struct hrtimer_cpu_base - the per cpu clock bases
158 * @lock: lock protecting the base and associated clock bases
160 * @clock_base: array of clock bases for this cpu
161 * @expires_next: absolute time of the next event which was scheduled
162 * via clock_set_next_event()
163 * @hres_active: State of high resolution mode
164 * @hang_detected: The last hrtimer interrupt detected a hang
165 * @nr_events: Total number of hrtimer interrupt events
166 * @nr_retries: Total number of hrtimer interrupt retries
167 * @nr_hangs: Total number of hrtimer interrupt hangs
168 * @max_hang_time: Maximum time spent in hrtimer_interrupt
170 struct hrtimer_cpu_base {
172 struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
173 #ifdef CONFIG_HIGH_RES_TIMERS
174 ktime_t expires_next;
177 unsigned long nr_events;
178 unsigned long nr_retries;
179 unsigned long nr_hangs;
180 ktime_t max_hang_time;
184 static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
186 timer->_expires = time;
187 timer->_softexpires = time;
190 static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
192 timer->_softexpires = time;
193 timer->_expires = ktime_add_safe(time, delta);
196 static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta)
198 timer->_softexpires = time;
199 timer->_expires = ktime_add_safe(time, ns_to_ktime(delta));
202 static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
204 timer->_expires.tv64 = tv64;
205 timer->_softexpires.tv64 = tv64;
208 static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
210 timer->_expires = ktime_add_safe(timer->_expires, time);
211 timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
214 static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
216 timer->_expires = ktime_add_ns(timer->_expires, ns);
217 timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
220 static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
222 return timer->_expires;
225 static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
227 return timer->_softexpires;
230 static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
232 return timer->_expires.tv64;
234 static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
236 return timer->_softexpires.tv64;
239 static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
241 return ktime_to_ns(timer->_expires);
244 static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
246 return ktime_sub(timer->_expires, timer->base->get_time());
249 #ifdef CONFIG_HIGH_RES_TIMERS
250 struct clock_event_device;
252 extern void clock_was_set(void);
253 extern void hres_timers_resume(void);
254 extern void hrtimer_interrupt(struct clock_event_device *dev);
257 * In high resolution mode the time reference must be read accurate
259 static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
261 return timer->base->get_time();
264 static inline int hrtimer_is_hres_active(struct hrtimer *timer)
266 return timer->base->cpu_base->hres_active;
269 extern void hrtimer_peek_ahead_timers(void);
272 * The resolution of the clocks. The resolution value is returned in
273 * the clock_getres() system call to give application programmers an
274 * idea of the (in)accuracy of timers. Timer values are rounded up to
275 * this resolution values.
277 # define HIGH_RES_NSEC 1
278 # define KTIME_HIGH_RES (ktime_t) { .tv64 = HIGH_RES_NSEC }
279 # define MONOTONIC_RES_NSEC HIGH_RES_NSEC
280 # define KTIME_MONOTONIC_RES KTIME_HIGH_RES
284 # define MONOTONIC_RES_NSEC LOW_RES_NSEC
285 # define KTIME_MONOTONIC_RES KTIME_LOW_RES
288 * clock_was_set() is a NOP for non- high-resolution systems. The
289 * time-sorted order guarantees that a timer does not expire early and
290 * is expired in the next softirq when the clock was advanced.
292 static inline void clock_was_set(void) { }
293 static inline void hrtimer_peek_ahead_timers(void) { }
295 static inline void hres_timers_resume(void) { }
298 * In non high resolution mode the time reference is taken from
299 * the base softirq time variable.
301 static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
303 return timer->base->softirq_time;
306 static inline int hrtimer_is_hres_active(struct hrtimer *timer)
312 extern ktime_t ktime_get(void);
313 extern ktime_t ktime_get_real(void);
316 DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
319 /* Exported timer functions: */
321 /* Initialize timers: */
322 extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
323 enum hrtimer_mode mode);
325 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
326 extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
327 enum hrtimer_mode mode);
329 extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
331 static inline void hrtimer_init_on_stack(struct hrtimer *timer,
332 clockid_t which_clock,
333 enum hrtimer_mode mode)
335 hrtimer_init(timer, which_clock, mode);
337 static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
340 /* Basic timer operations: */
341 extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
342 const enum hrtimer_mode mode);
343 extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
344 unsigned long range_ns, const enum hrtimer_mode mode);
346 __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
347 unsigned long delta_ns,
348 const enum hrtimer_mode mode, int wakeup);
350 extern int hrtimer_cancel(struct hrtimer *timer);
351 extern int hrtimer_try_to_cancel(struct hrtimer *timer);
353 static inline int hrtimer_start_expires(struct hrtimer *timer,
354 enum hrtimer_mode mode)
358 soft = hrtimer_get_softexpires(timer);
359 hard = hrtimer_get_expires(timer);
360 delta = ktime_to_ns(ktime_sub(hard, soft));
361 return hrtimer_start_range_ns(timer, soft, delta, mode);
364 static inline int hrtimer_restart(struct hrtimer *timer)
366 return hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
370 extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
371 extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
373 extern ktime_t hrtimer_get_next_event(void);
376 * A timer is active, when it is enqueued into the rbtree or the callback
377 * function is running.
379 static inline int hrtimer_active(const struct hrtimer *timer)
381 return timer->state != HRTIMER_STATE_INACTIVE;
385 * Helper function to check, whether the timer is on one of the queues
387 static inline int hrtimer_is_queued(struct hrtimer *timer)
389 return timer->state & HRTIMER_STATE_ENQUEUED;
393 * Helper function to check, whether the timer is running the callback
396 static inline int hrtimer_callback_running(struct hrtimer *timer)
398 return timer->state & HRTIMER_STATE_CALLBACK;
401 /* Forward a hrtimer so it expires after now: */
403 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
405 /* Forward a hrtimer so it expires after the hrtimer's current now */
406 static inline u64 hrtimer_forward_now(struct hrtimer *timer,
409 return hrtimer_forward(timer, timer->base->get_time(), interval);
413 extern long hrtimer_nanosleep(struct timespec *rqtp,
414 struct timespec __user *rmtp,
415 const enum hrtimer_mode mode,
416 const clockid_t clockid);
417 extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
419 extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
420 struct task_struct *tsk);
422 extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
423 const enum hrtimer_mode mode);
424 extern int schedule_hrtimeout_range_clock(ktime_t *expires,
425 unsigned long delta, const enum hrtimer_mode mode, int clock);
426 extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
428 /* Soft interrupt function to run the hrtimer queues: */
429 extern void hrtimer_run_queues(void);
430 extern void hrtimer_run_pending(void);
432 /* Bootup initialization: */
433 extern void __init hrtimers_init(void);
435 #if BITS_PER_LONG < 64
436 extern u64 ktime_divns(const ktime_t kt, s64 div);
437 #else /* BITS_PER_LONG < 64 */
438 # define ktime_divns(kt, div) (u64)((kt).tv64 / (div))
441 /* Show pending timers: */
442 extern void sysrq_timer_list_show(void);