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/percpu.h>
23 #include <linux/timer.h>
24 #include <linux/timerqueue.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
56 * The callback state is not part of the timer->state because clearing it would
57 * mean touching the timer after the callback, this makes it impossible to free
58 * the timer from the callback function.
60 * Therefore we track the callback state in:
62 * timer->base->cpu_base->running == timer
64 * On SMP it is possible to have a "callback function running and enqueued"
65 * status. 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.
70 * All state transitions are protected by cpu_base->lock.
72 #define HRTIMER_STATE_INACTIVE 0x00
73 #define HRTIMER_STATE_ENQUEUED 0x01
76 * struct hrtimer - the basic hrtimer structure
77 * @node: timerqueue node, which also manages node.expires,
78 * the absolute expiry time in the hrtimers internal
79 * representation. The time is related to the clock on
80 * which the timer is based. Is setup by adding
81 * slack to the _softexpires value. For non range timers
82 * identical to _softexpires.
83 * @_softexpires: the absolute earliest expiry time of the hrtimer.
84 * The time which was given as expiry time when the timer
86 * @function: timer expiry callback function
87 * @base: pointer to the timer base (per cpu and per clock)
88 * @state: state information (See bit values above)
89 * @is_rel: Set if the timer was armed relative
91 * The hrtimer structure must be initialized by hrtimer_init()
94 struct timerqueue_node node
;
96 enum hrtimer_restart (*function
)(struct hrtimer
*);
97 struct hrtimer_clock_base
*base
;
103 * struct hrtimer_sleeper - simple sleeper structure
104 * @timer: embedded timer structure
105 * @task: task to wake up
107 * task is set to NULL, when the timer expires.
109 struct hrtimer_sleeper
{
110 struct hrtimer timer
;
111 struct task_struct
*task
;
115 # define HRTIMER_CLOCK_BASE_ALIGN 64
117 # define HRTIMER_CLOCK_BASE_ALIGN 32
121 * struct hrtimer_clock_base - the timer base for a specific clock
122 * @cpu_base: per cpu clock base
123 * @index: clock type index for per_cpu support when moving a
124 * timer to a base on another cpu.
125 * @clockid: clock id for per_cpu support
126 * @active: red black tree root node for the active timers
127 * @get_time: function to retrieve the current time of the clock
128 * @offset: offset of this clock to the monotonic base
130 struct hrtimer_clock_base
{
131 struct hrtimer_cpu_base
*cpu_base
;
134 struct timerqueue_head active
;
135 ktime_t (*get_time
)(void);
137 } __attribute__((__aligned__(HRTIMER_CLOCK_BASE_ALIGN
)));
139 enum hrtimer_base_type
{
140 HRTIMER_BASE_MONOTONIC
,
141 HRTIMER_BASE_REALTIME
,
142 HRTIMER_BASE_BOOTTIME
,
144 HRTIMER_MAX_CLOCK_BASES
,
148 * struct hrtimer_cpu_base - the per cpu clock bases
149 * @lock: lock protecting the base and associated clock bases
151 * @seq: seqcount around __run_hrtimer
152 * @running: pointer to the currently running hrtimer
154 * @active_bases: Bitfield to mark bases with active timers
155 * @clock_was_set_seq: Sequence counter of clock was set events
156 * @migration_enabled: The migration of hrtimers to other cpus is enabled
157 * @nohz_active: The nohz functionality is enabled
158 * @expires_next: absolute time of the next event which was scheduled
159 * via clock_set_next_event()
160 * @next_timer: Pointer to the first expiring timer
161 * @in_hrtirq: hrtimer_interrupt() is currently executing
162 * @hres_active: State of high resolution mode
163 * @hang_detected: The last hrtimer interrupt detected a hang
164 * @nr_events: Total number of hrtimer interrupt events
165 * @nr_retries: Total number of hrtimer interrupt retries
166 * @nr_hangs: Total number of hrtimer interrupt hangs
167 * @max_hang_time: Maximum time spent in hrtimer_interrupt
168 * @clock_base: array of clock bases for this cpu
170 * Note: next_timer is just an optimization for __remove_hrtimer().
171 * Do not dereference the pointer because it is not reliable on
172 * cross cpu removals.
174 struct hrtimer_cpu_base
{
177 struct hrtimer
*running
;
179 unsigned int active_bases
;
180 unsigned int clock_was_set_seq
;
181 bool migration_enabled
;
183 #ifdef CONFIG_HIGH_RES_TIMERS
184 unsigned int in_hrtirq
: 1,
187 ktime_t expires_next
;
188 struct hrtimer
*next_timer
;
189 unsigned int nr_events
;
190 unsigned int nr_retries
;
191 unsigned int nr_hangs
;
192 unsigned int max_hang_time
;
194 struct hrtimer_clock_base clock_base
[HRTIMER_MAX_CLOCK_BASES
];
195 } ____cacheline_aligned
;
197 static inline void hrtimer_set_expires(struct hrtimer
*timer
, ktime_t time
)
199 BUILD_BUG_ON(sizeof(struct hrtimer_clock_base
) > HRTIMER_CLOCK_BASE_ALIGN
);
201 timer
->node
.expires
= time
;
202 timer
->_softexpires
= time
;
205 static inline void hrtimer_set_expires_range(struct hrtimer
*timer
, ktime_t time
, ktime_t delta
)
207 timer
->_softexpires
= time
;
208 timer
->node
.expires
= ktime_add_safe(time
, delta
);
211 static inline void hrtimer_set_expires_range_ns(struct hrtimer
*timer
, ktime_t time
, u64 delta
)
213 timer
->_softexpires
= time
;
214 timer
->node
.expires
= ktime_add_safe(time
, ns_to_ktime(delta
));
217 static inline void hrtimer_set_expires_tv64(struct hrtimer
*timer
, s64 tv64
)
219 timer
->node
.expires
= tv64
;
220 timer
->_softexpires
= tv64
;
223 static inline void hrtimer_add_expires(struct hrtimer
*timer
, ktime_t time
)
225 timer
->node
.expires
= ktime_add_safe(timer
->node
.expires
, time
);
226 timer
->_softexpires
= ktime_add_safe(timer
->_softexpires
, time
);
229 static inline void hrtimer_add_expires_ns(struct hrtimer
*timer
, u64 ns
)
231 timer
->node
.expires
= ktime_add_ns(timer
->node
.expires
, ns
);
232 timer
->_softexpires
= ktime_add_ns(timer
->_softexpires
, ns
);
235 static inline ktime_t
hrtimer_get_expires(const struct hrtimer
*timer
)
237 return timer
->node
.expires
;
240 static inline ktime_t
hrtimer_get_softexpires(const struct hrtimer
*timer
)
242 return timer
->_softexpires
;
245 static inline s64
hrtimer_get_expires_tv64(const struct hrtimer
*timer
)
247 return timer
->node
.expires
;
249 static inline s64
hrtimer_get_softexpires_tv64(const struct hrtimer
*timer
)
251 return timer
->_softexpires
;
254 static inline s64
hrtimer_get_expires_ns(const struct hrtimer
*timer
)
256 return ktime_to_ns(timer
->node
.expires
);
259 static inline ktime_t
hrtimer_expires_remaining(const struct hrtimer
*timer
)
261 return ktime_sub(timer
->node
.expires
, timer
->base
->get_time());
264 static inline ktime_t
hrtimer_cb_get_time(struct hrtimer
*timer
)
266 return timer
->base
->get_time();
269 #ifdef CONFIG_HIGH_RES_TIMERS
270 struct clock_event_device
;
272 extern void hrtimer_interrupt(struct clock_event_device
*dev
);
274 static inline int hrtimer_is_hres_active(struct hrtimer
*timer
)
276 return timer
->base
->cpu_base
->hres_active
;
280 * The resolution of the clocks. The resolution value is returned in
281 * the clock_getres() system call to give application programmers an
282 * idea of the (in)accuracy of timers. Timer values are rounded up to
283 * this resolution values.
285 # define HIGH_RES_NSEC 1
286 # define KTIME_HIGH_RES (HIGH_RES_NSEC)
287 # define MONOTONIC_RES_NSEC HIGH_RES_NSEC
288 # define KTIME_MONOTONIC_RES KTIME_HIGH_RES
290 extern void clock_was_set_delayed(void);
292 extern unsigned int hrtimer_resolution
;
296 # define MONOTONIC_RES_NSEC LOW_RES_NSEC
297 # define KTIME_MONOTONIC_RES KTIME_LOW_RES
299 #define hrtimer_resolution (unsigned int)LOW_RES_NSEC
301 static inline int hrtimer_is_hres_active(struct hrtimer
*timer
)
306 static inline void clock_was_set_delayed(void) { }
310 static inline ktime_t
311 __hrtimer_expires_remaining_adjusted(const struct hrtimer
*timer
, ktime_t now
)
313 ktime_t rem
= ktime_sub(timer
->node
.expires
, now
);
316 * Adjust relative timers for the extra we added in
317 * hrtimer_start_range_ns() to prevent short timeouts.
319 if (IS_ENABLED(CONFIG_TIME_LOW_RES
) && timer
->is_rel
)
320 rem
-= hrtimer_resolution
;
324 static inline ktime_t
325 hrtimer_expires_remaining_adjusted(const struct hrtimer
*timer
)
327 return __hrtimer_expires_remaining_adjusted(timer
,
328 timer
->base
->get_time());
331 extern void clock_was_set(void);
332 #ifdef CONFIG_TIMERFD
333 extern void timerfd_clock_was_set(void);
335 static inline void timerfd_clock_was_set(void) { }
337 extern void hrtimers_resume(void);
339 DECLARE_PER_CPU(struct tick_device
, tick_cpu_device
);
342 /* Exported timer functions: */
344 /* Initialize timers: */
345 extern void hrtimer_init(struct hrtimer
*timer
, clockid_t which_clock
,
346 enum hrtimer_mode mode
);
348 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
349 extern void hrtimer_init_on_stack(struct hrtimer
*timer
, clockid_t which_clock
,
350 enum hrtimer_mode mode
);
352 extern void destroy_hrtimer_on_stack(struct hrtimer
*timer
);
354 static inline void hrtimer_init_on_stack(struct hrtimer
*timer
,
355 clockid_t which_clock
,
356 enum hrtimer_mode mode
)
358 hrtimer_init(timer
, which_clock
, mode
);
360 static inline void destroy_hrtimer_on_stack(struct hrtimer
*timer
) { }
363 /* Basic timer operations: */
364 extern void hrtimer_start_range_ns(struct hrtimer
*timer
, ktime_t tim
,
365 u64 range_ns
, const enum hrtimer_mode mode
);
368 * hrtimer_start - (re)start an hrtimer on the current CPU
369 * @timer: the timer to be added
371 * @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or
372 * relative (HRTIMER_MODE_REL)
374 static inline void hrtimer_start(struct hrtimer
*timer
, ktime_t tim
,
375 const enum hrtimer_mode mode
)
377 hrtimer_start_range_ns(timer
, tim
, 0, mode
);
380 extern int hrtimer_cancel(struct hrtimer
*timer
);
381 extern int hrtimer_try_to_cancel(struct hrtimer
*timer
);
383 static inline void hrtimer_start_expires(struct hrtimer
*timer
,
384 enum hrtimer_mode mode
)
388 soft
= hrtimer_get_softexpires(timer
);
389 hard
= hrtimer_get_expires(timer
);
390 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
391 hrtimer_start_range_ns(timer
, soft
, delta
, mode
);
394 static inline void hrtimer_restart(struct hrtimer
*timer
)
396 hrtimer_start_expires(timer
, HRTIMER_MODE_ABS
);
400 extern ktime_t
__hrtimer_get_remaining(const struct hrtimer
*timer
, bool adjust
);
402 static inline ktime_t
hrtimer_get_remaining(const struct hrtimer
*timer
)
404 return __hrtimer_get_remaining(timer
, false);
407 extern u64
hrtimer_get_next_event(void);
409 extern bool hrtimer_active(const struct hrtimer
*timer
);
412 * Helper function to check, whether the timer is on one of the queues
414 static inline int hrtimer_is_queued(struct hrtimer
*timer
)
416 return timer
->state
& HRTIMER_STATE_ENQUEUED
;
420 * Helper function to check, whether the timer is running the callback
423 static inline int hrtimer_callback_running(struct hrtimer
*timer
)
425 return timer
->base
->cpu_base
->running
== timer
;
428 /* Forward a hrtimer so it expires after now: */
430 hrtimer_forward(struct hrtimer
*timer
, ktime_t now
, ktime_t interval
);
433 * hrtimer_forward_now - forward the timer expiry so it expires after now
434 * @timer: hrtimer to forward
435 * @interval: the interval to forward
437 * Forward the timer expiry so it will expire after the current time
438 * of the hrtimer clock base. Returns the number of overruns.
440 * Can be safely called from the callback function of @timer. If
441 * called from other contexts @timer must neither be enqueued nor
442 * running the callback and the caller needs to take care of
445 * Note: This only updates the timer expiry value and does not requeue
448 static inline u64
hrtimer_forward_now(struct hrtimer
*timer
,
451 return hrtimer_forward(timer
, timer
->base
->get_time(), interval
);
456 extern int nanosleep_copyout(struct restart_block
*, struct timespec64
*);
457 extern long hrtimer_nanosleep(const struct timespec64
*rqtp
,
458 const enum hrtimer_mode mode
,
459 const clockid_t clockid
);
461 extern void hrtimer_init_sleeper(struct hrtimer_sleeper
*sl
,
462 struct task_struct
*tsk
);
464 extern int schedule_hrtimeout_range(ktime_t
*expires
, u64 delta
,
465 const enum hrtimer_mode mode
);
466 extern int schedule_hrtimeout_range_clock(ktime_t
*expires
,
468 const enum hrtimer_mode mode
,
470 extern int schedule_hrtimeout(ktime_t
*expires
, const enum hrtimer_mode mode
);
472 /* Soft interrupt function to run the hrtimer queues: */
473 extern void hrtimer_run_queues(void);
475 /* Bootup initialization: */
476 extern void __init
hrtimers_init(void);
478 /* Show pending timers: */
479 extern void sysrq_timer_list_show(void);
481 int hrtimers_prepare_cpu(unsigned int cpu
);
482 #ifdef CONFIG_HOTPLUG_CPU
483 int hrtimers_dead_cpu(unsigned int cpu
);
485 #define hrtimers_dead_cpu NULL