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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> |
23 | #include <linux/percpu.h> |
24 | #include <linux/timer.h> |
25 | #include <linux/timerqueue.h> |
26 | |
27 | struct hrtimer_clock_base; |
28 | struct hrtimer_cpu_base; |
29 | |
30 | /* |
31 | * Mode arguments of xxx_hrtimer functions: |
32 | */ |
33 | enum hrtimer_mode { |
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, |
39 | }; |
40 | |
41 | /* |
42 | * Return values for the callback function |
43 | */ |
44 | enum hrtimer_restart { |
45 | HRTIMER_NORESTART, /* Timer is not restarted */ |
46 | HRTIMER_RESTART, /* Timer must be restarted */ |
47 | }; |
48 | |
49 | /* |
50 | * Values to track state of the timer |
51 | * |
52 | * Possible states: |
53 | * |
54 | * 0x00 inactive |
55 | * 0x01 enqueued into rbtree |
56 | * 0x02 callback function running |
57 | * 0x04 timer is migrated to another cpu |
58 | * |
59 | * Special cases: |
60 | * 0x03 callback function running and enqueued |
61 | * (was requeued on another CPU) |
62 | * 0x05 timer was migrated on CPU hotunplug |
63 | * |
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. |
71 | * |
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. |
77 | * |
78 | * All state transitions are protected by cpu_base->lock. |
79 | */ |
80 | #define HRTIMER_STATE_INACTIVE 0x00 |
81 | #define HRTIMER_STATE_ENQUEUED 0x01 |
82 | #define HRTIMER_STATE_CALLBACK 0x02 |
83 | #define HRTIMER_STATE_MIGRATE 0x04 |
84 | |
85 | /** |
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 |
95 | * was armed. |
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_site: timer statistics field to store the site where the timer |
100 | * was started |
101 | * @start_comm: timer statistics field to store the name of the process which |
102 | * started the timer |
103 | * @start_pid: timer statistics field to store the pid of the task which |
104 | * started the timer |
105 | * |
106 | * The hrtimer structure must be initialized by hrtimer_init() |
107 | */ |
108 | struct hrtimer { |
109 | struct timerqueue_node node; |
110 | ktime_t _softexpires; |
111 | enum hrtimer_restart (*function)(struct hrtimer *); |
112 | struct hrtimer_clock_base *base; |
113 | unsigned long state; |
114 | #ifdef CONFIG_TIMER_STATS |
115 | int start_pid; |
116 | void *start_site; |
117 | char start_comm[16]; |
118 | #endif |
119 | }; |
120 | |
121 | /** |
122 | * struct hrtimer_sleeper - simple sleeper structure |
123 | * @timer: embedded timer structure |
124 | * @task: task to wake up |
125 | * |
126 | * task is set to NULL, when the timer expires. |
127 | */ |
128 | struct hrtimer_sleeper { |
129 | struct hrtimer timer; |
130 | struct task_struct *task; |
131 | }; |
132 | |
133 | /** |
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 |
144 | */ |
145 | struct hrtimer_clock_base { |
146 | struct hrtimer_cpu_base *cpu_base; |
147 | int index; |
148 | clockid_t clockid; |
149 | struct timerqueue_head active; |
150 | ktime_t resolution; |
151 | ktime_t (*get_time)(void); |
152 | ktime_t softirq_time; |
153 | ktime_t offset; |
154 | }; |
155 | |
156 | enum hrtimer_base_type { |
157 | HRTIMER_BASE_MONOTONIC, |
158 | HRTIMER_BASE_REALTIME, |
159 | HRTIMER_BASE_BOOTTIME, |
160 | HRTIMER_BASE_TAI, |
161 | HRTIMER_MAX_CLOCK_BASES, |
162 | }; |
163 | |
164 | /* |
165 | * struct hrtimer_cpu_base - the per cpu clock bases |
166 | * @lock: lock protecting the base and associated clock bases |
167 | * and timers |
168 | * @active_bases: Bitfield to mark bases with active timers |
169 | * @clock_was_set: Indicates that clock was set from irq context. |
170 | * @expires_next: absolute time of the next event which was scheduled |
171 | * via clock_set_next_event() |
172 | * @hres_active: State of high resolution mode |
173 | * @hang_detected: The last hrtimer interrupt detected a hang |
174 | * @nr_events: Total number of hrtimer interrupt events |
175 | * @nr_retries: Total number of hrtimer interrupt retries |
176 | * @nr_hangs: Total number of hrtimer interrupt hangs |
177 | * @max_hang_time: Maximum time spent in hrtimer_interrupt |
178 | * @clock_base: array of clock bases for this cpu |
179 | */ |
180 | struct hrtimer_cpu_base { |
181 | raw_spinlock_t lock; |
182 | unsigned int active_bases; |
183 | unsigned int clock_was_set; |
184 | #ifdef CONFIG_HIGH_RES_TIMERS |
185 | ktime_t expires_next; |
186 | int hres_active; |
187 | int hang_detected; |
188 | unsigned long nr_events; |
189 | unsigned long nr_retries; |
190 | unsigned long nr_hangs; |
191 | ktime_t max_hang_time; |
192 | #endif |
193 | struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; |
194 | }; |
195 | |
196 | static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) |
197 | { |
198 | timer->node.expires = time; |
199 | timer->_softexpires = time; |
200 | } |
201 | |
202 | static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta) |
203 | { |
204 | timer->_softexpires = time; |
205 | timer->node.expires = ktime_add_safe(time, delta); |
206 | } |
207 | |
208 | static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta) |
209 | { |
210 | timer->_softexpires = time; |
211 | timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta)); |
212 | } |
213 | |
214 | static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64) |
215 | { |
216 | timer->node.expires.tv64 = tv64; |
217 | timer->_softexpires.tv64 = tv64; |
218 | } |
219 | |
220 | static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time) |
221 | { |
222 | timer->node.expires = ktime_add_safe(timer->node.expires, time); |
223 | timer->_softexpires = ktime_add_safe(timer->_softexpires, time); |
224 | } |
225 | |
226 | static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns) |
227 | { |
228 | timer->node.expires = ktime_add_ns(timer->node.expires, ns); |
229 | timer->_softexpires = ktime_add_ns(timer->_softexpires, ns); |
230 | } |
231 | |
232 | static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer) |
233 | { |
234 | return timer->node.expires; |
235 | } |
236 | |
237 | static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer) |
238 | { |
239 | return timer->_softexpires; |
240 | } |
241 | |
242 | static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer) |
243 | { |
244 | return timer->node.expires.tv64; |
245 | } |
246 | static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer) |
247 | { |
248 | return timer->_softexpires.tv64; |
249 | } |
250 | |
251 | static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer) |
252 | { |
253 | return ktime_to_ns(timer->node.expires); |
254 | } |
255 | |
256 | static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer) |
257 | { |
258 | return ktime_sub(timer->node.expires, timer->base->get_time()); |
259 | } |
260 | |
261 | #ifdef CONFIG_HIGH_RES_TIMERS |
262 | struct clock_event_device; |
263 | |
264 | extern void hrtimer_interrupt(struct clock_event_device *dev); |
265 | |
266 | /* |
267 | * In high resolution mode the time reference must be read accurate |
268 | */ |
269 | static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) |
270 | { |
271 | return timer->base->get_time(); |
272 | } |
273 | |
274 | static inline int hrtimer_is_hres_active(struct hrtimer *timer) |
275 | { |
276 | return timer->base->cpu_base->hres_active; |
277 | } |
278 | |
279 | extern void hrtimer_peek_ahead_timers(void); |
280 | |
281 | /* |
282 | * The resolution of the clocks. The resolution value is returned in |
283 | * the clock_getres() system call to give application programmers an |
284 | * idea of the (in)accuracy of timers. Timer values are rounded up to |
285 | * this resolution values. |
286 | */ |
287 | # define HIGH_RES_NSEC 1 |
288 | # define KTIME_HIGH_RES (ktime_t) { .tv64 = HIGH_RES_NSEC } |
289 | # define MONOTONIC_RES_NSEC HIGH_RES_NSEC |
290 | # define KTIME_MONOTONIC_RES KTIME_HIGH_RES |
291 | |
292 | extern void clock_was_set_delayed(void); |
293 | |
294 | #else |
295 | |
296 | # define MONOTONIC_RES_NSEC LOW_RES_NSEC |
297 | # define KTIME_MONOTONIC_RES KTIME_LOW_RES |
298 | |
299 | static inline void hrtimer_peek_ahead_timers(void) { } |
300 | |
301 | /* |
302 | * In non high resolution mode the time reference is taken from |
303 | * the base softirq time variable. |
304 | */ |
305 | static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) |
306 | { |
307 | return timer->base->softirq_time; |
308 | } |
309 | |
310 | static inline int hrtimer_is_hres_active(struct hrtimer *timer) |
311 | { |
312 | return 0; |
313 | } |
314 | |
315 | static inline void clock_was_set_delayed(void) { } |
316 | |
317 | #endif |
318 | |
319 | extern void clock_was_set(void); |
320 | #ifdef CONFIG_TIMERFD |
321 | extern void timerfd_clock_was_set(void); |
322 | #else |
323 | static inline void timerfd_clock_was_set(void) { } |
324 | #endif |
325 | extern void hrtimers_resume(void); |
326 | |
327 | extern ktime_t ktime_get(void); |
328 | extern ktime_t ktime_get_real(void); |
329 | extern ktime_t ktime_get_boottime(void); |
330 | extern ktime_t ktime_get_monotonic_offset(void); |
331 | extern ktime_t ktime_get_clocktai(void); |
332 | extern ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot, |
333 | ktime_t *offs_tai); |
334 | |
335 | DECLARE_PER_CPU(struct tick_device, tick_cpu_device); |
336 | |
337 | |
338 | /* Exported timer functions: */ |
339 | |
340 | /* Initialize timers: */ |
341 | extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, |
342 | enum hrtimer_mode mode); |
343 | |
344 | #ifdef CONFIG_DEBUG_OBJECTS_TIMERS |
345 | extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock, |
346 | enum hrtimer_mode mode); |
347 | |
348 | extern void destroy_hrtimer_on_stack(struct hrtimer *timer); |
349 | #else |
350 | static inline void hrtimer_init_on_stack(struct hrtimer *timer, |
351 | clockid_t which_clock, |
352 | enum hrtimer_mode mode) |
353 | { |
354 | hrtimer_init(timer, which_clock, mode); |
355 | } |
356 | static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { } |
357 | #endif |
358 | |
359 | /* Basic timer operations: */ |
360 | extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, |
361 | const enum hrtimer_mode mode); |
362 | extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, |
363 | unsigned long range_ns, const enum hrtimer_mode mode); |
364 | extern int |
365 | __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, |
366 | unsigned long delta_ns, |
367 | const enum hrtimer_mode mode, int wakeup); |
368 | |
369 | extern int hrtimer_cancel(struct hrtimer *timer); |
370 | extern int hrtimer_try_to_cancel(struct hrtimer *timer); |
371 | |
372 | static inline int hrtimer_start_expires(struct hrtimer *timer, |
373 | enum hrtimer_mode mode) |
374 | { |
375 | unsigned long delta; |
376 | ktime_t soft, hard; |
377 | soft = hrtimer_get_softexpires(timer); |
378 | hard = hrtimer_get_expires(timer); |
379 | delta = ktime_to_ns(ktime_sub(hard, soft)); |
380 | return hrtimer_start_range_ns(timer, soft, delta, mode); |
381 | } |
382 | |
383 | static inline int hrtimer_restart(struct hrtimer *timer) |
384 | { |
385 | return hrtimer_start_expires(timer, HRTIMER_MODE_ABS); |
386 | } |
387 | |
388 | /* Query timers: */ |
389 | extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer); |
390 | extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp); |
391 | |
392 | extern ktime_t hrtimer_get_next_event(void); |
393 | |
394 | /* |
395 | * A timer is active, when it is enqueued into the rbtree or the |
396 | * callback function is running or it's in the state of being migrated |
397 | * to another cpu. |
398 | */ |
399 | static inline int hrtimer_active(const struct hrtimer *timer) |
400 | { |
401 | return timer->state != HRTIMER_STATE_INACTIVE; |
402 | } |
403 | |
404 | /* |
405 | * Helper function to check, whether the timer is on one of the queues |
406 | */ |
407 | static inline int hrtimer_is_queued(struct hrtimer *timer) |
408 | { |
409 | return timer->state & HRTIMER_STATE_ENQUEUED; |
410 | } |
411 | |
412 | /* |
413 | * Helper function to check, whether the timer is running the callback |
414 | * function |
415 | */ |
416 | static inline int hrtimer_callback_running(struct hrtimer *timer) |
417 | { |
418 | return timer->state & HRTIMER_STATE_CALLBACK; |
419 | } |
420 | |
421 | /* Forward a hrtimer so it expires after now: */ |
422 | extern u64 |
423 | hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); |
424 | |
425 | /* Forward a hrtimer so it expires after the hrtimer's current now */ |
426 | static inline u64 hrtimer_forward_now(struct hrtimer *timer, |
427 | ktime_t interval) |
428 | { |
429 | return hrtimer_forward(timer, timer->base->get_time(), interval); |
430 | } |
431 | |
432 | /* Precise sleep: */ |
433 | extern long hrtimer_nanosleep(struct timespec *rqtp, |
434 | struct timespec __user *rmtp, |
435 | const enum hrtimer_mode mode, |
436 | const clockid_t clockid); |
437 | extern long hrtimer_nanosleep_restart(struct restart_block *restart_block); |
438 | |
439 | extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, |
440 | struct task_struct *tsk); |
441 | |
442 | extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta, |
443 | const enum hrtimer_mode mode); |
444 | extern int schedule_hrtimeout_range_clock(ktime_t *expires, |
445 | unsigned long delta, const enum hrtimer_mode mode, int clock); |
446 | extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode); |
447 | |
448 | /* Soft interrupt function to run the hrtimer queues: */ |
449 | extern void hrtimer_run_queues(void); |
450 | extern void hrtimer_run_pending(void); |
451 | |
452 | /* Bootup initialization: */ |
453 | extern void __init hrtimers_init(void); |
454 | |
455 | #if BITS_PER_LONG < 64 |
456 | extern u64 ktime_divns(const ktime_t kt, s64 div); |
457 | #else /* BITS_PER_LONG < 64 */ |
458 | # define ktime_divns(kt, div) (u64)((kt).tv64 / (div)) |
459 | #endif |
460 | |
461 | /* Show pending timers: */ |
462 | extern void sysrq_timer_list_show(void); |
463 | |
464 | #endif |
465 |
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