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1/*
2 * include/linux/hrtimer.h
3 *
4 * hrtimers - High-resolution kernel timers
5 *
6 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
7 * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
8 *
9 * data type definitions, declarations, prototypes
10 *
11 * Started by: Thomas Gleixner and Ingo Molnar
12 *
13 * For licencing details see kernel-base/COPYING
14 */
15#ifndef _LINUX_HRTIMER_H
16#define _LINUX_HRTIMER_H
17
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>
40b86062 23#include <linux/percpu.h>
507e1231 24#include <linux/timer.h>
998adc3d 25#include <linux/timerqueue.h>
c0a31329 26
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27struct hrtimer_clock_base;
28struct hrtimer_cpu_base;
29
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30/*
31 * Mode arguments of xxx_hrtimer functions:
32 */
33enum hrtimer_mode {
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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,
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39};
40
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41/*
42 * Return values for the callback function
43 */
c0a31329 44enum hrtimer_restart {
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45 HRTIMER_NORESTART, /* Timer is not restarted */
46 HRTIMER_RESTART, /* Timer must be restarted */
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47};
48
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49/*
50 * Values to track state of the timer
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51 *
52 * Possible states:
53 *
54 * 0x00 inactive
55 * 0x01 enqueued into rbtree
56 * 0x02 callback function running
54cdfdb4 57 *
b00c1a99 58 * Special cases:
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59 * 0x03 callback function running and enqueued
60 * (was requeued on another CPU)
b00c1a99 61 * 0x09 timer was migrated on CPU hotunplug
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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.
69 *
3eb05676 70 * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state to
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71 * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario.
72 *
73 * All state transitions are protected by cpu_base->lock.
74 */
75#define HRTIMER_STATE_INACTIVE 0x00
76#define HRTIMER_STATE_ENQUEUED 0x01
77#define HRTIMER_STATE_CALLBACK 0x02
ca109491 78#define HRTIMER_STATE_MIGRATE 0x04
303e967f 79
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80/**
81 * struct hrtimer - the basic hrtimer structure
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82 * @node: timerqueue node, which also manages node.expires,
83 * the absolute expiry time in the hrtimers internal
c0a31329 84 * representation. The time is related to the clock on
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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
90 * was armed.
c0a31329 91 * @function: timer expiry callback function
c0a31329 92 * @base: pointer to the timer base (per cpu and per clock)
303e967f 93 * @state: state information (See bit values above)
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94 * @start_site: timer statistics field to store the site where the timer
95 * was started
96 * @start_comm: timer statistics field to store the name of the process which
97 * started the timer
98 * @start_pid: timer statistics field to store the pid of the task which
99 * started the timer
c0a31329 100 *
54cdfdb4 101 * The hrtimer structure must be initialized by hrtimer_init()
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102 */
103struct hrtimer {
998adc3d 104 struct timerqueue_node node;
654c8e0b 105 ktime_t _softexpires;
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106 enum hrtimer_restart (*function)(struct hrtimer *);
107 struct hrtimer_clock_base *base;
303e967f 108 unsigned long state;
82f67cd9 109#ifdef CONFIG_TIMER_STATS
1b024690 110 int start_pid;
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111 void *start_site;
112 char start_comm[16];
82f67cd9 113#endif
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114};
115
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116/**
117 * struct hrtimer_sleeper - simple sleeper structure
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118 * @timer: embedded timer structure
119 * @task: task to wake up
120 *
121 * task is set to NULL, when the timer expires.
122 */
123struct hrtimer_sleeper {
124 struct hrtimer timer;
125 struct task_struct *task;
126};
127
c0a31329 128/**
d1d67174 129 * struct hrtimer_clock_base - the timer base for a specific clock
05fb6bf0 130 * @cpu_base: per cpu clock base
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131 * @index: clock type index for per_cpu support when moving a
132 * timer to a base on another cpu.
92127c7a 133 * @active: red black tree root node for the active timers
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134 * @resolution: the resolution of the clock, in nanoseconds
135 * @get_time: function to retrieve the current time of the clock
92127c7a 136 * @softirq_time: the time when running the hrtimer queue in the softirq
54cdfdb4 137 * @offset: offset of this clock to the monotonic base
c0a31329 138 */
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139struct hrtimer_clock_base {
140 struct hrtimer_cpu_base *cpu_base;
c0a31329 141 clockid_t index;
998adc3d 142 struct timerqueue_head active;
e2787630 143 ktime_t resolution;
c0a31329 144 ktime_t (*get_time)(void);
92127c7a 145 ktime_t softirq_time;
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146#ifdef CONFIG_HIGH_RES_TIMERS
147 ktime_t offset;
54cdfdb4 148#endif
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149};
150
151#define HRTIMER_MAX_CLOCK_BASES 2
152
153/*
154 * struct hrtimer_cpu_base - the per cpu clock bases
155 * @lock: lock protecting the base and associated clock bases
156 * and timers
3c8aa39d 157 * @clock_base: array of clock bases for this cpu
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158 * @expires_next: absolute time of the next event which was scheduled
159 * via clock_set_next_event()
160 * @hres_active: State of high resolution mode
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161 * @hang_detected: The last hrtimer interrupt detected a hang
162 * @nr_events: Total number of hrtimer interrupt events
163 * @nr_retries: Total number of hrtimer interrupt retries
164 * @nr_hangs: Total number of hrtimer interrupt hangs
165 * @max_hang_time: Maximum time spent in hrtimer_interrupt
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166 */
167struct hrtimer_cpu_base {
ecb49d1a 168 raw_spinlock_t lock;
3c8aa39d 169 struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
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170#ifdef CONFIG_HIGH_RES_TIMERS
171 ktime_t expires_next;
172 int hres_active;
41d2e494 173 int hang_detected;
54cdfdb4 174 unsigned long nr_events;
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175 unsigned long nr_retries;
176 unsigned long nr_hangs;
177 ktime_t max_hang_time;
54cdfdb4 178#endif
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179};
180
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181static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
182{
998adc3d 183 timer->node.expires = time;
654c8e0b 184 timer->_softexpires = time;
63ca243b 185}
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186
187static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
188{
189 timer->_softexpires = time;
998adc3d 190 timer->node.expires = ktime_add_safe(time, delta);
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191}
192
193static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta)
194{
195 timer->_softexpires = time;
998adc3d 196 timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta));
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197}
198
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199static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
200{
998adc3d 201 timer->node.expires.tv64 = tv64;
654c8e0b 202 timer->_softexpires.tv64 = tv64;
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203}
204
205static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
206{
998adc3d 207 timer->node.expires = ktime_add_safe(timer->node.expires, time);
654c8e0b 208 timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
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209}
210
7597bc94 211static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
63ca243b 212{
998adc3d 213 timer->node.expires = ktime_add_ns(timer->node.expires, ns);
654c8e0b 214 timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
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215}
216
217static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
218{
998adc3d 219 return timer->node.expires;
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220}
221
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222static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
223{
224 return timer->_softexpires;
225}
226
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227static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
228{
998adc3d 229 return timer->node.expires.tv64;
63ca243b 230}
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231static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
232{
233 return timer->_softexpires.tv64;
234}
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235
236static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
237{
998adc3d 238 return ktime_to_ns(timer->node.expires);
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239}
240
241static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
242{
998adc3d 243 return ktime_sub(timer->node.expires, timer->base->get_time());
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244}
245
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246#ifdef CONFIG_HIGH_RES_TIMERS
247struct clock_event_device;
248
249extern void clock_was_set(void);
995f054f 250extern void hres_timers_resume(void);
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251extern void hrtimer_interrupt(struct clock_event_device *dev);
252
253/*
254 * In high resolution mode the time reference must be read accurate
255 */
256static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
257{
258 return timer->base->get_time();
259}
260
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261static inline int hrtimer_is_hres_active(struct hrtimer *timer)
262{
263 return timer->base->cpu_base->hres_active;
264}
265
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266extern void hrtimer_peek_ahead_timers(void);
267
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268/*
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.
273 */
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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
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277# define KTIME_MONOTONIC_RES KTIME_HIGH_RES
278
279#else
280
151db1fc 281# define MONOTONIC_RES_NSEC LOW_RES_NSEC
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282# define KTIME_MONOTONIC_RES KTIME_LOW_RES
283
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284/*
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.
288 */
54cdfdb4 289static inline void clock_was_set(void) { }
2075eb8d 290static inline void hrtimer_peek_ahead_timers(void) { }
54cdfdb4 291
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292static inline void hres_timers_resume(void) { }
293
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294/*
295 * In non high resolution mode the time reference is taken from
296 * the base softirq time variable.
297 */
298static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
299{
300 return timer->base->softirq_time;
301}
302
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303static inline int hrtimer_is_hres_active(struct hrtimer *timer)
304{
305 return 0;
306}
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307#endif
308
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309extern ktime_t ktime_get(void);
310extern ktime_t ktime_get_real(void);
becf8b5d 311
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312
313DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
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314
315
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316/* Exported timer functions: */
317
318/* Initialize timers: */
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319extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,
320 enum hrtimer_mode mode);
c0a31329 321
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322#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
323extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,
324 enum hrtimer_mode mode);
325
326extern void destroy_hrtimer_on_stack(struct hrtimer *timer);
327#else
328static inline void hrtimer_init_on_stack(struct hrtimer *timer,
329 clockid_t which_clock,
330 enum hrtimer_mode mode)
331{
332 hrtimer_init(timer, which_clock, mode);
333}
334static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
335#endif
336
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337/* Basic timer operations: */
338extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
339 const enum hrtimer_mode mode);
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340extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
341 unsigned long range_ns, const enum hrtimer_mode mode);
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342extern int
343__hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
344 unsigned long delta_ns,
345 const enum hrtimer_mode mode, int wakeup);
346
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347extern int hrtimer_cancel(struct hrtimer *timer);
348extern int hrtimer_try_to_cancel(struct hrtimer *timer);
349
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350static inline int hrtimer_start_expires(struct hrtimer *timer,
351 enum hrtimer_mode mode)
352{
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353 unsigned long delta;
354 ktime_t soft, hard;
355 soft = hrtimer_get_softexpires(timer);
356 hard = hrtimer_get_expires(timer);
357 delta = ktime_to_ns(ktime_sub(hard, soft));
4ce105d3 358 return hrtimer_start_range_ns(timer, soft, delta, mode);
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359}
360
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361static inline int hrtimer_restart(struct hrtimer *timer)
362{
654c8e0b 363 return hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
c9cb2e3d 364}
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365
366/* Query timers: */
367extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
368extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
369
69239749 370extern ktime_t hrtimer_get_next_event(void);
69239749 371
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372/*
373 * A timer is active, when it is enqueued into the rbtree or the callback
374 * function is running.
375 */
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376static inline int hrtimer_active(const struct hrtimer *timer)
377{
303e967f 378 return timer->state != HRTIMER_STATE_INACTIVE;
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379}
380
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381/*
382 * Helper function to check, whether the timer is on one of the queues
383 */
384static inline int hrtimer_is_queued(struct hrtimer *timer)
385{
ca109491 386 return timer->state & HRTIMER_STATE_ENQUEUED;
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387}
388
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389/*
390 * Helper function to check, whether the timer is running the callback
391 * function
392 */
393static inline int hrtimer_callback_running(struct hrtimer *timer)
394{
395 return timer->state & HRTIMER_STATE_CALLBACK;
396}
397
c0a31329 398/* Forward a hrtimer so it expires after now: */
4d672e7a 399extern u64
44f21475 400hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
c0a31329 401
5e05ad7d 402/* Forward a hrtimer so it expires after the hrtimer's current now */
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403static inline u64 hrtimer_forward_now(struct hrtimer *timer,
404 ktime_t interval)
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405{
406 return hrtimer_forward(timer, timer->base->get_time(), interval);
407}
408
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409/* Precise sleep: */
410extern long hrtimer_nanosleep(struct timespec *rqtp,
080344b9 411 struct timespec __user *rmtp,
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412 const enum hrtimer_mode mode,
413 const clockid_t clockid);
1711ef38 414extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
10c94ec1 415
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416extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
417 struct task_struct *tsk);
418
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419extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
420 const enum hrtimer_mode mode);
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421extern int schedule_hrtimeout_range_clock(ktime_t *expires,
422 unsigned long delta, const enum hrtimer_mode mode, int clock);
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423extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
424
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425/* Soft interrupt function to run the hrtimer queues: */
426extern void hrtimer_run_queues(void);
d3d74453 427extern void hrtimer_run_pending(void);
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428
429/* Bootup initialization: */
430extern void __init hrtimers_init(void);
431
79bf2bb3 432#if BITS_PER_LONG < 64
4d672e7a 433extern u64 ktime_divns(const ktime_t kt, s64 div);
79bf2bb3 434#else /* BITS_PER_LONG < 64 */
4d672e7a 435# define ktime_divns(kt, div) (u64)((kt).tv64 / (div))
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436#endif
437
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438/* Show pending timers: */
439extern void sysrq_timer_list_show(void);
440
c0a31329 441#endif