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>
25 #include <linux/timerqueue.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
57 * 0x04 timer is migrated to another cpu
60 * 0x03 callback function running and enqueued
61 * (was requeued on another CPU)
62 * 0x05 timer was migrated on CPU hotunplug
64 * The "callback function running and enqueued" status is only possible on
65 * SMP. It happens for example when a posix timer expired and the callback
66 * queued a signal. Between dropping the lock which protects the posix timer
67 * and reacquiring the base lock of the hrtimer, another CPU can deliver the
68 * signal and rearm the timer. We have to preserve the callback running state,
69 * as otherwise the timer could be removed before the softirq code finishes the
70 * the handling of the timer.
72 * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state
73 * to preserve the HRTIMER_STATE_CALLBACK in the above scenario. This
74 * also affects HRTIMER_STATE_MIGRATE where the preservation is not
75 * necessary. HRTIMER_STATE_MIGRATE is cleared after the timer is
76 * enqueued on the new cpu.
78 * All state transitions are protected by cpu_base->lock.
80 #define HRTIMER_STATE_INACTIVE 0x00
81 #define HRTIMER_STATE_ENQUEUED 0x01
82 #define HRTIMER_STATE_CALLBACK 0x02
83 #define HRTIMER_STATE_MIGRATE 0x04
86 * struct hrtimer - the basic hrtimer structure
87 * @node: timerqueue node, which also manages node.expires,
88 * the absolute expiry time in the hrtimers internal
89 * representation. The time is related to the clock on
90 * which the timer is based. Is setup by adding
91 * slack to the _softexpires value. For non range timers
92 * identical to _softexpires.
93 * @_softexpires: the absolute earliest expiry time of the hrtimer.
94 * The time which was given as expiry time when the timer
96 * @function: timer expiry callback function
97 * @base: pointer to the timer base (per cpu and per clock)
98 * @state: state information (See bit values above)
99 * @start_pid: timer statistics field to store the pid of the task which
101 * @start_site: timer statistics field to store the site where the timer
103 * @start_comm: timer statistics field to store the name of the process which
106 * The hrtimer structure must be initialized by hrtimer_init()
109 struct timerqueue_node node
;
110 ktime_t _softexpires
;
111 enum hrtimer_restart (*function
)(struct hrtimer
*);
112 struct hrtimer_clock_base
*base
;
114 #ifdef CONFIG_TIMER_STATS
122 * struct hrtimer_sleeper - simple sleeper structure
123 * @timer: embedded timer structure
124 * @task: task to wake up
126 * task is set to NULL, when the timer expires.
128 struct hrtimer_sleeper
{
129 struct hrtimer timer
;
130 struct task_struct
*task
;
134 * struct hrtimer_clock_base - the timer base for a specific clock
135 * @cpu_base: per cpu clock base
136 * @index: clock type index for per_cpu support when moving a
137 * timer to a base on another cpu.
138 * @clockid: clock id for per_cpu support
139 * @active: red black tree root node for the active timers
140 * @resolution: the resolution of the clock, in nanoseconds
141 * @get_time: function to retrieve the current time of the clock
142 * @softirq_time: the time when running the hrtimer queue in the softirq
143 * @offset: offset of this clock to the monotonic base
145 struct hrtimer_clock_base
{
146 struct hrtimer_cpu_base
*cpu_base
;
149 struct timerqueue_head active
;
151 ktime_t (*get_time
)(void);
152 ktime_t softirq_time
;
156 enum hrtimer_base_type
{
157 HRTIMER_BASE_MONOTONIC
,
158 HRTIMER_BASE_REALTIME
,
159 HRTIMER_BASE_BOOTTIME
,
161 HRTIMER_MAX_CLOCK_BASES
,
165 * struct hrtimer_cpu_base - the per cpu clock bases
166 * @lock: lock protecting the base and associated clock bases
169 * @active_bases: Bitfield to mark bases with active timers
170 * @clock_was_set: Indicates that clock was set from irq context.
171 * @expires_next: absolute time of the next event which was scheduled
172 * via clock_set_next_event()
173 * @hres_active: State of high resolution mode
174 * @hang_detected: The last hrtimer interrupt detected a hang
175 * @nr_events: Total number of hrtimer interrupt events
176 * @nr_retries: Total number of hrtimer interrupt retries
177 * @nr_hangs: Total number of hrtimer interrupt hangs
178 * @max_hang_time: Maximum time spent in hrtimer_interrupt
179 * @clock_base: array of clock bases for this cpu
181 struct hrtimer_cpu_base
{
184 unsigned int active_bases
;
185 unsigned int clock_was_set
;
186 #ifdef CONFIG_HIGH_RES_TIMERS
187 ktime_t expires_next
;
190 unsigned long nr_events
;
191 unsigned long nr_retries
;
192 unsigned long nr_hangs
;
193 ktime_t max_hang_time
;
195 struct hrtimer_clock_base clock_base
[HRTIMER_MAX_CLOCK_BASES
];
198 static inline void hrtimer_set_expires(struct hrtimer
*timer
, ktime_t time
)
200 timer
->node
.expires
= time
;
201 timer
->_softexpires
= time
;
204 static inline void hrtimer_set_expires_range(struct hrtimer
*timer
, ktime_t time
, ktime_t delta
)
206 timer
->_softexpires
= time
;
207 timer
->node
.expires
= ktime_add_safe(time
, delta
);
210 static inline void hrtimer_set_expires_range_ns(struct hrtimer
*timer
, ktime_t time
, unsigned long delta
)
212 timer
->_softexpires
= time
;
213 timer
->node
.expires
= ktime_add_safe(time
, ns_to_ktime(delta
));
216 static inline void hrtimer_set_expires_tv64(struct hrtimer
*timer
, s64 tv64
)
218 timer
->node
.expires
.tv64
= tv64
;
219 timer
->_softexpires
.tv64
= tv64
;
222 static inline void hrtimer_add_expires(struct hrtimer
*timer
, ktime_t time
)
224 timer
->node
.expires
= ktime_add_safe(timer
->node
.expires
, time
);
225 timer
->_softexpires
= ktime_add_safe(timer
->_softexpires
, time
);
228 static inline void hrtimer_add_expires_ns(struct hrtimer
*timer
, u64 ns
)
230 timer
->node
.expires
= ktime_add_ns(timer
->node
.expires
, ns
);
231 timer
->_softexpires
= ktime_add_ns(timer
->_softexpires
, ns
);
234 static inline ktime_t
hrtimer_get_expires(const struct hrtimer
*timer
)
236 return timer
->node
.expires
;
239 static inline ktime_t
hrtimer_get_softexpires(const struct hrtimer
*timer
)
241 return timer
->_softexpires
;
244 static inline s64
hrtimer_get_expires_tv64(const struct hrtimer
*timer
)
246 return timer
->node
.expires
.tv64
;
248 static inline s64
hrtimer_get_softexpires_tv64(const struct hrtimer
*timer
)
250 return timer
->_softexpires
.tv64
;
253 static inline s64
hrtimer_get_expires_ns(const struct hrtimer
*timer
)
255 return ktime_to_ns(timer
->node
.expires
);
258 static inline ktime_t
hrtimer_expires_remaining(const struct hrtimer
*timer
)
260 return ktime_sub(timer
->node
.expires
, timer
->base
->get_time());
263 #ifdef CONFIG_HIGH_RES_TIMERS
264 struct clock_event_device
;
266 extern void hrtimer_interrupt(struct clock_event_device
*dev
);
269 * In high resolution mode the time reference must be read accurate
271 static inline ktime_t
hrtimer_cb_get_time(struct hrtimer
*timer
)
273 return timer
->base
->get_time();
276 static inline int hrtimer_is_hres_active(struct hrtimer
*timer
)
278 return timer
->base
->cpu_base
->hres_active
;
281 extern void hrtimer_peek_ahead_timers(void);
284 * The resolution of the clocks. The resolution value is returned in
285 * the clock_getres() system call to give application programmers an
286 * idea of the (in)accuracy of timers. Timer values are rounded up to
287 * this resolution values.
289 # define HIGH_RES_NSEC 1
290 # define KTIME_HIGH_RES (ktime_t) { .tv64 = HIGH_RES_NSEC }
291 # define MONOTONIC_RES_NSEC HIGH_RES_NSEC
292 # define KTIME_MONOTONIC_RES KTIME_HIGH_RES
294 extern void clock_was_set_delayed(void);
298 # define MONOTONIC_RES_NSEC LOW_RES_NSEC
299 # define KTIME_MONOTONIC_RES KTIME_LOW_RES
301 static inline void hrtimer_peek_ahead_timers(void) { }
304 * In non high resolution mode the time reference is taken from
305 * the base softirq time variable.
307 static inline ktime_t
hrtimer_cb_get_time(struct hrtimer
*timer
)
309 return timer
->base
->softirq_time
;
312 static inline int hrtimer_is_hres_active(struct hrtimer
*timer
)
317 static inline void clock_was_set_delayed(void) { }
321 extern void clock_was_set(void);
322 #ifdef CONFIG_TIMERFD
323 extern void timerfd_clock_was_set(void);
325 static inline void timerfd_clock_was_set(void) { }
327 extern void hrtimers_resume(void);
329 DECLARE_PER_CPU(struct tick_device
, tick_cpu_device
);
332 /* Exported timer functions: */
334 /* Initialize timers: */
335 extern void hrtimer_init(struct hrtimer
*timer
, clockid_t which_clock
,
336 enum hrtimer_mode mode
);
338 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
339 extern void hrtimer_init_on_stack(struct hrtimer
*timer
, clockid_t which_clock
,
340 enum hrtimer_mode mode
);
342 extern void destroy_hrtimer_on_stack(struct hrtimer
*timer
);
344 static inline void hrtimer_init_on_stack(struct hrtimer
*timer
,
345 clockid_t which_clock
,
346 enum hrtimer_mode mode
)
348 hrtimer_init(timer
, which_clock
, mode
);
350 static inline void destroy_hrtimer_on_stack(struct hrtimer
*timer
) { }
353 /* Basic timer operations: */
354 extern int hrtimer_start(struct hrtimer
*timer
, ktime_t tim
,
355 const enum hrtimer_mode mode
);
356 extern int hrtimer_start_range_ns(struct hrtimer
*timer
, ktime_t tim
,
357 unsigned long range_ns
, const enum hrtimer_mode mode
);
359 __hrtimer_start_range_ns(struct hrtimer
*timer
, ktime_t tim
,
360 unsigned long delta_ns
,
361 const enum hrtimer_mode mode
, int wakeup
);
363 extern int hrtimer_cancel(struct hrtimer
*timer
);
364 extern int hrtimer_try_to_cancel(struct hrtimer
*timer
);
366 static inline int hrtimer_start_expires(struct hrtimer
*timer
,
367 enum hrtimer_mode mode
)
371 soft
= hrtimer_get_softexpires(timer
);
372 hard
= hrtimer_get_expires(timer
);
373 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
374 return hrtimer_start_range_ns(timer
, soft
, delta
, mode
);
377 static inline int hrtimer_restart(struct hrtimer
*timer
)
379 return hrtimer_start_expires(timer
, HRTIMER_MODE_ABS
);
383 extern ktime_t
hrtimer_get_remaining(const struct hrtimer
*timer
);
384 extern int hrtimer_get_res(const clockid_t which_clock
, struct timespec
*tp
);
386 extern ktime_t
hrtimer_get_next_event(void);
389 * A timer is active, when it is enqueued into the rbtree or the
390 * callback function is running or it's in the state of being migrated
393 static inline int hrtimer_active(const struct hrtimer
*timer
)
395 return timer
->state
!= HRTIMER_STATE_INACTIVE
;
399 * Helper function to check, whether the timer is on one of the queues
401 static inline int hrtimer_is_queued(struct hrtimer
*timer
)
403 return timer
->state
& HRTIMER_STATE_ENQUEUED
;
407 * Helper function to check, whether the timer is running the callback
410 static inline int hrtimer_callback_running(struct hrtimer
*timer
)
412 return timer
->state
& HRTIMER_STATE_CALLBACK
;
415 /* Forward a hrtimer so it expires after now: */
417 hrtimer_forward(struct hrtimer
*timer
, ktime_t now
, ktime_t interval
);
419 /* Forward a hrtimer so it expires after the hrtimer's current now */
420 static inline u64
hrtimer_forward_now(struct hrtimer
*timer
,
423 return hrtimer_forward(timer
, timer
->base
->get_time(), interval
);
427 extern long hrtimer_nanosleep(struct timespec
*rqtp
,
428 struct timespec __user
*rmtp
,
429 const enum hrtimer_mode mode
,
430 const clockid_t clockid
);
431 extern long hrtimer_nanosleep_restart(struct restart_block
*restart_block
);
433 extern void hrtimer_init_sleeper(struct hrtimer_sleeper
*sl
,
434 struct task_struct
*tsk
);
436 extern int schedule_hrtimeout_range(ktime_t
*expires
, unsigned long delta
,
437 const enum hrtimer_mode mode
);
438 extern int schedule_hrtimeout_range_clock(ktime_t
*expires
,
439 unsigned long delta
, const enum hrtimer_mode mode
, int clock
);
440 extern int schedule_hrtimeout(ktime_t
*expires
, const enum hrtimer_mode mode
);
442 /* Soft interrupt function to run the hrtimer queues: */
443 extern void hrtimer_run_queues(void);
444 extern void hrtimer_run_pending(void);
446 /* Bootup initialization: */
447 extern void __init
hrtimers_init(void);
449 /* Show pending timers: */
450 extern void sysrq_timer_list_show(void);