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1 | /* |
2 | * linux/kernel/hrtimer.c | |
3 | * | |
4 | * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de> | |
5 | * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar | |
6 | * | |
7 | * High-resolution kernel timers | |
8 | * | |
9 | * In contrast to the low-resolution timeout API implemented in | |
10 | * kernel/timer.c, hrtimers provide finer resolution and accuracy | |
11 | * depending on system configuration and capabilities. | |
12 | * | |
13 | * These timers are currently used for: | |
14 | * - itimers | |
15 | * - POSIX timers | |
16 | * - nanosleep | |
17 | * - precise in-kernel timing | |
18 | * | |
19 | * Started by: Thomas Gleixner and Ingo Molnar | |
20 | * | |
21 | * Credits: | |
22 | * based on kernel/timer.c | |
23 | * | |
24 | * For licencing details see kernel-base/COPYING | |
25 | */ | |
26 | ||
27 | #include <linux/cpu.h> | |
28 | #include <linux/module.h> | |
29 | #include <linux/percpu.h> | |
30 | #include <linux/hrtimer.h> | |
31 | #include <linux/notifier.h> | |
32 | #include <linux/syscalls.h> | |
33 | #include <linux/interrupt.h> | |
34 | ||
35 | #include <asm/uaccess.h> | |
36 | ||
37 | /** | |
38 | * ktime_get - get the monotonic time in ktime_t format | |
39 | * | |
40 | * returns the time in ktime_t format | |
41 | */ | |
42 | static ktime_t ktime_get(void) | |
43 | { | |
44 | struct timespec now; | |
45 | ||
46 | ktime_get_ts(&now); | |
47 | ||
48 | return timespec_to_ktime(now); | |
49 | } | |
50 | ||
51 | /** | |
52 | * ktime_get_real - get the real (wall-) time in ktime_t format | |
53 | * | |
54 | * returns the time in ktime_t format | |
55 | */ | |
56 | static ktime_t ktime_get_real(void) | |
57 | { | |
58 | struct timespec now; | |
59 | ||
60 | getnstimeofday(&now); | |
61 | ||
62 | return timespec_to_ktime(now); | |
63 | } | |
64 | ||
65 | EXPORT_SYMBOL_GPL(ktime_get_real); | |
66 | ||
67 | /* | |
68 | * The timer bases: | |
69 | */ | |
70 | ||
71 | #define MAX_HRTIMER_BASES 2 | |
72 | ||
73 | static DEFINE_PER_CPU(struct hrtimer_base, hrtimer_bases[MAX_HRTIMER_BASES]) = | |
74 | { | |
75 | { | |
76 | .index = CLOCK_REALTIME, | |
77 | .get_time = &ktime_get_real, | |
78 | .resolution = KTIME_REALTIME_RES, | |
79 | }, | |
80 | { | |
81 | .index = CLOCK_MONOTONIC, | |
82 | .get_time = &ktime_get, | |
83 | .resolution = KTIME_MONOTONIC_RES, | |
84 | }, | |
85 | }; | |
86 | ||
87 | /** | |
88 | * ktime_get_ts - get the monotonic clock in timespec format | |
89 | * | |
90 | * @ts: pointer to timespec variable | |
91 | * | |
92 | * The function calculates the monotonic clock from the realtime | |
93 | * clock and the wall_to_monotonic offset and stores the result | |
94 | * in normalized timespec format in the variable pointed to by ts. | |
95 | */ | |
96 | void ktime_get_ts(struct timespec *ts) | |
97 | { | |
98 | struct timespec tomono; | |
99 | unsigned long seq; | |
100 | ||
101 | do { | |
102 | seq = read_seqbegin(&xtime_lock); | |
103 | getnstimeofday(ts); | |
104 | tomono = wall_to_monotonic; | |
105 | ||
106 | } while (read_seqretry(&xtime_lock, seq)); | |
107 | ||
108 | set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, | |
109 | ts->tv_nsec + tomono.tv_nsec); | |
110 | } | |
111 | ||
112 | /* | |
113 | * Functions and macros which are different for UP/SMP systems are kept in a | |
114 | * single place | |
115 | */ | |
116 | #ifdef CONFIG_SMP | |
117 | ||
118 | #define set_curr_timer(b, t) do { (b)->curr_timer = (t); } while (0) | |
119 | ||
120 | /* | |
121 | * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock | |
122 | * means that all timers which are tied to this base via timer->base are | |
123 | * locked, and the base itself is locked too. | |
124 | * | |
125 | * So __run_timers/migrate_timers can safely modify all timers which could | |
126 | * be found on the lists/queues. | |
127 | * | |
128 | * When the timer's base is locked, and the timer removed from list, it is | |
129 | * possible to set timer->base = NULL and drop the lock: the timer remains | |
130 | * locked. | |
131 | */ | |
132 | static struct hrtimer_base *lock_hrtimer_base(const struct hrtimer *timer, | |
133 | unsigned long *flags) | |
134 | { | |
135 | struct hrtimer_base *base; | |
136 | ||
137 | for (;;) { | |
138 | base = timer->base; | |
139 | if (likely(base != NULL)) { | |
140 | spin_lock_irqsave(&base->lock, *flags); | |
141 | if (likely(base == timer->base)) | |
142 | return base; | |
143 | /* The timer has migrated to another CPU: */ | |
144 | spin_unlock_irqrestore(&base->lock, *flags); | |
145 | } | |
146 | cpu_relax(); | |
147 | } | |
148 | } | |
149 | ||
150 | /* | |
151 | * Switch the timer base to the current CPU when possible. | |
152 | */ | |
153 | static inline struct hrtimer_base * | |
154 | switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_base *base) | |
155 | { | |
156 | struct hrtimer_base *new_base; | |
157 | ||
158 | new_base = &__get_cpu_var(hrtimer_bases[base->index]); | |
159 | ||
160 | if (base != new_base) { | |
161 | /* | |
162 | * We are trying to schedule the timer on the local CPU. | |
163 | * However we can't change timer's base while it is running, | |
164 | * so we keep it on the same CPU. No hassle vs. reprogramming | |
165 | * the event source in the high resolution case. The softirq | |
166 | * code will take care of this when the timer function has | |
167 | * completed. There is no conflict as we hold the lock until | |
168 | * the timer is enqueued. | |
169 | */ | |
170 | if (unlikely(base->curr_timer == timer)) | |
171 | return base; | |
172 | ||
173 | /* See the comment in lock_timer_base() */ | |
174 | timer->base = NULL; | |
175 | spin_unlock(&base->lock); | |
176 | spin_lock(&new_base->lock); | |
177 | timer->base = new_base; | |
178 | } | |
179 | return new_base; | |
180 | } | |
181 | ||
182 | #else /* CONFIG_SMP */ | |
183 | ||
184 | #define set_curr_timer(b, t) do { } while (0) | |
185 | ||
186 | static inline struct hrtimer_base * | |
187 | lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) | |
188 | { | |
189 | struct hrtimer_base *base = timer->base; | |
190 | ||
191 | spin_lock_irqsave(&base->lock, *flags); | |
192 | ||
193 | return base; | |
194 | } | |
195 | ||
196 | #define switch_hrtimer_base(t, b) (b) | |
197 | ||
198 | #endif /* !CONFIG_SMP */ | |
199 | ||
200 | /* | |
201 | * Functions for the union type storage format of ktime_t which are | |
202 | * too large for inlining: | |
203 | */ | |
204 | #if BITS_PER_LONG < 64 | |
205 | # ifndef CONFIG_KTIME_SCALAR | |
206 | /** | |
207 | * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable | |
208 | * | |
209 | * @kt: addend | |
210 | * @nsec: the scalar nsec value to add | |
211 | * | |
212 | * Returns the sum of kt and nsec in ktime_t format | |
213 | */ | |
214 | ktime_t ktime_add_ns(const ktime_t kt, u64 nsec) | |
215 | { | |
216 | ktime_t tmp; | |
217 | ||
218 | if (likely(nsec < NSEC_PER_SEC)) { | |
219 | tmp.tv64 = nsec; | |
220 | } else { | |
221 | unsigned long rem = do_div(nsec, NSEC_PER_SEC); | |
222 | ||
223 | tmp = ktime_set((long)nsec, rem); | |
224 | } | |
225 | ||
226 | return ktime_add(kt, tmp); | |
227 | } | |
228 | ||
229 | #else /* CONFIG_KTIME_SCALAR */ | |
230 | ||
231 | # endif /* !CONFIG_KTIME_SCALAR */ | |
232 | ||
233 | /* | |
234 | * Divide a ktime value by a nanosecond value | |
235 | */ | |
236 | static unsigned long ktime_divns(const ktime_t kt, nsec_t div) | |
237 | { | |
238 | u64 dclc, inc, dns; | |
239 | int sft = 0; | |
240 | ||
241 | dclc = dns = ktime_to_ns(kt); | |
242 | inc = div; | |
243 | /* Make sure the divisor is less than 2^32: */ | |
244 | while (div >> 32) { | |
245 | sft++; | |
246 | div >>= 1; | |
247 | } | |
248 | dclc >>= sft; | |
249 | do_div(dclc, (unsigned long) div); | |
250 | ||
251 | return (unsigned long) dclc; | |
252 | } | |
253 | ||
254 | #else /* BITS_PER_LONG < 64 */ | |
255 | # define ktime_divns(kt, div) (unsigned long)((kt).tv64 / (div)) | |
256 | #endif /* BITS_PER_LONG >= 64 */ | |
257 | ||
258 | /* | |
259 | * Counterpart to lock_timer_base above: | |
260 | */ | |
261 | static inline | |
262 | void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) | |
263 | { | |
264 | spin_unlock_irqrestore(&timer->base->lock, *flags); | |
265 | } | |
266 | ||
267 | /** | |
268 | * hrtimer_forward - forward the timer expiry | |
269 | * | |
270 | * @timer: hrtimer to forward | |
271 | * @interval: the interval to forward | |
272 | * | |
273 | * Forward the timer expiry so it will expire in the future. | |
274 | * The number of overruns is added to the overrun field. | |
275 | */ | |
276 | unsigned long | |
277 | hrtimer_forward(struct hrtimer *timer, const ktime_t interval) | |
278 | { | |
279 | unsigned long orun = 1; | |
280 | ktime_t delta, now; | |
281 | ||
282 | now = timer->base->get_time(); | |
283 | ||
284 | delta = ktime_sub(now, timer->expires); | |
285 | ||
286 | if (delta.tv64 < 0) | |
287 | return 0; | |
288 | ||
289 | if (unlikely(delta.tv64 >= interval.tv64)) { | |
290 | nsec_t incr = ktime_to_ns(interval); | |
291 | ||
292 | orun = ktime_divns(delta, incr); | |
293 | timer->expires = ktime_add_ns(timer->expires, incr * orun); | |
294 | if (timer->expires.tv64 > now.tv64) | |
295 | return orun; | |
296 | /* | |
297 | * This (and the ktime_add() below) is the | |
298 | * correction for exact: | |
299 | */ | |
300 | orun++; | |
301 | } | |
302 | timer->expires = ktime_add(timer->expires, interval); | |
303 | ||
304 | return orun; | |
305 | } | |
306 | ||
307 | /* | |
308 | * enqueue_hrtimer - internal function to (re)start a timer | |
309 | * | |
310 | * The timer is inserted in expiry order. Insertion into the | |
311 | * red black tree is O(log(n)). Must hold the base lock. | |
312 | */ | |
313 | static void enqueue_hrtimer(struct hrtimer *timer, struct hrtimer_base *base) | |
314 | { | |
315 | struct rb_node **link = &base->active.rb_node; | |
316 | struct list_head *prev = &base->pending; | |
317 | struct rb_node *parent = NULL; | |
318 | struct hrtimer *entry; | |
319 | ||
320 | /* | |
321 | * Find the right place in the rbtree: | |
322 | */ | |
323 | while (*link) { | |
324 | parent = *link; | |
325 | entry = rb_entry(parent, struct hrtimer, node); | |
326 | /* | |
327 | * We dont care about collisions. Nodes with | |
328 | * the same expiry time stay together. | |
329 | */ | |
330 | if (timer->expires.tv64 < entry->expires.tv64) | |
331 | link = &(*link)->rb_left; | |
332 | else { | |
333 | link = &(*link)->rb_right; | |
334 | prev = &entry->list; | |
335 | } | |
336 | } | |
337 | ||
338 | /* | |
339 | * Insert the timer to the rbtree and to the sorted list: | |
340 | */ | |
341 | rb_link_node(&timer->node, parent, link); | |
342 | rb_insert_color(&timer->node, &base->active); | |
343 | list_add(&timer->list, prev); | |
344 | ||
345 | timer->state = HRTIMER_PENDING; | |
346 | } | |
347 | ||
348 | ||
349 | /* | |
350 | * __remove_hrtimer - internal function to remove a timer | |
351 | * | |
352 | * Caller must hold the base lock. | |
353 | */ | |
354 | static void __remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base) | |
355 | { | |
356 | /* | |
357 | * Remove the timer from the sorted list and from the rbtree: | |
358 | */ | |
359 | list_del(&timer->list); | |
360 | rb_erase(&timer->node, &base->active); | |
361 | } | |
362 | ||
363 | /* | |
364 | * remove hrtimer, called with base lock held | |
365 | */ | |
366 | static inline int | |
367 | remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base) | |
368 | { | |
369 | if (hrtimer_active(timer)) { | |
370 | __remove_hrtimer(timer, base); | |
371 | timer->state = HRTIMER_INACTIVE; | |
372 | return 1; | |
373 | } | |
374 | return 0; | |
375 | } | |
376 | ||
377 | /** | |
378 | * hrtimer_start - (re)start an relative timer on the current CPU | |
379 | * | |
380 | * @timer: the timer to be added | |
381 | * @tim: expiry time | |
382 | * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL) | |
383 | * | |
384 | * Returns: | |
385 | * 0 on success | |
386 | * 1 when the timer was active | |
387 | */ | |
388 | int | |
389 | hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) | |
390 | { | |
391 | struct hrtimer_base *base, *new_base; | |
392 | unsigned long flags; | |
393 | int ret; | |
394 | ||
395 | base = lock_hrtimer_base(timer, &flags); | |
396 | ||
397 | /* Remove an active timer from the queue: */ | |
398 | ret = remove_hrtimer(timer, base); | |
399 | ||
400 | /* Switch the timer base, if necessary: */ | |
401 | new_base = switch_hrtimer_base(timer, base); | |
402 | ||
403 | if (mode == HRTIMER_REL) | |
404 | tim = ktime_add(tim, new_base->get_time()); | |
405 | timer->expires = tim; | |
406 | ||
407 | enqueue_hrtimer(timer, new_base); | |
408 | ||
409 | unlock_hrtimer_base(timer, &flags); | |
410 | ||
411 | return ret; | |
412 | } | |
413 | ||
414 | /** | |
415 | * hrtimer_try_to_cancel - try to deactivate a timer | |
416 | * | |
417 | * @timer: hrtimer to stop | |
418 | * | |
419 | * Returns: | |
420 | * 0 when the timer was not active | |
421 | * 1 when the timer was active | |
422 | * -1 when the timer is currently excuting the callback function and | |
423 | * can not be stopped | |
424 | */ | |
425 | int hrtimer_try_to_cancel(struct hrtimer *timer) | |
426 | { | |
427 | struct hrtimer_base *base; | |
428 | unsigned long flags; | |
429 | int ret = -1; | |
430 | ||
431 | base = lock_hrtimer_base(timer, &flags); | |
432 | ||
433 | if (base->curr_timer != timer) | |
434 | ret = remove_hrtimer(timer, base); | |
435 | ||
436 | unlock_hrtimer_base(timer, &flags); | |
437 | ||
438 | return ret; | |
439 | ||
440 | } | |
441 | ||
442 | /** | |
443 | * hrtimer_cancel - cancel a timer and wait for the handler to finish. | |
444 | * | |
445 | * @timer: the timer to be cancelled | |
446 | * | |
447 | * Returns: | |
448 | * 0 when the timer was not active | |
449 | * 1 when the timer was active | |
450 | */ | |
451 | int hrtimer_cancel(struct hrtimer *timer) | |
452 | { | |
453 | for (;;) { | |
454 | int ret = hrtimer_try_to_cancel(timer); | |
455 | ||
456 | if (ret >= 0) | |
457 | return ret; | |
458 | } | |
459 | } | |
460 | ||
461 | /** | |
462 | * hrtimer_get_remaining - get remaining time for the timer | |
463 | * | |
464 | * @timer: the timer to read | |
465 | */ | |
466 | ktime_t hrtimer_get_remaining(const struct hrtimer *timer) | |
467 | { | |
468 | struct hrtimer_base *base; | |
469 | unsigned long flags; | |
470 | ktime_t rem; | |
471 | ||
472 | base = lock_hrtimer_base(timer, &flags); | |
473 | rem = ktime_sub(timer->expires, timer->base->get_time()); | |
474 | unlock_hrtimer_base(timer, &flags); | |
475 | ||
476 | return rem; | |
477 | } | |
478 | ||
479 | /** | |
480 | * hrtimer_rebase - rebase an initialized hrtimer to a different base | |
481 | * | |
482 | * @timer: the timer to be rebased | |
483 | * @clock_id: the clock to be used | |
484 | */ | |
485 | void hrtimer_rebase(struct hrtimer *timer, const clockid_t clock_id) | |
486 | { | |
487 | struct hrtimer_base *bases; | |
488 | ||
489 | bases = per_cpu(hrtimer_bases, raw_smp_processor_id()); | |
490 | timer->base = &bases[clock_id]; | |
491 | } | |
492 | ||
493 | /** | |
494 | * hrtimer_init - initialize a timer to the given clock | |
495 | * | |
496 | * @timer: the timer to be initialized | |
497 | * @clock_id: the clock to be used | |
498 | */ | |
499 | void hrtimer_init(struct hrtimer *timer, const clockid_t clock_id) | |
500 | { | |
501 | memset(timer, 0, sizeof(struct hrtimer)); | |
502 | hrtimer_rebase(timer, clock_id); | |
503 | } | |
504 | ||
505 | /** | |
506 | * hrtimer_get_res - get the timer resolution for a clock | |
507 | * | |
508 | * @which_clock: which clock to query | |
509 | * @tp: pointer to timespec variable to store the resolution | |
510 | * | |
511 | * Store the resolution of the clock selected by which_clock in the | |
512 | * variable pointed to by tp. | |
513 | */ | |
514 | int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp) | |
515 | { | |
516 | struct hrtimer_base *bases; | |
517 | ||
518 | tp->tv_sec = 0; | |
519 | bases = per_cpu(hrtimer_bases, raw_smp_processor_id()); | |
520 | tp->tv_nsec = bases[which_clock].resolution; | |
521 | ||
522 | return 0; | |
523 | } | |
524 | ||
525 | /* | |
526 | * Expire the per base hrtimer-queue: | |
527 | */ | |
528 | static inline void run_hrtimer_queue(struct hrtimer_base *base) | |
529 | { | |
530 | ktime_t now = base->get_time(); | |
531 | ||
532 | spin_lock_irq(&base->lock); | |
533 | ||
534 | while (!list_empty(&base->pending)) { | |
535 | struct hrtimer *timer; | |
536 | int (*fn)(void *); | |
537 | int restart; | |
538 | void *data; | |
539 | ||
540 | timer = list_entry(base->pending.next, struct hrtimer, list); | |
541 | if (now.tv64 <= timer->expires.tv64) | |
542 | break; | |
543 | ||
544 | fn = timer->function; | |
545 | data = timer->data; | |
546 | set_curr_timer(base, timer); | |
547 | __remove_hrtimer(timer, base); | |
548 | spin_unlock_irq(&base->lock); | |
549 | ||
550 | /* | |
551 | * fn == NULL is special case for the simplest timer | |
552 | * variant - wake up process and do not restart: | |
553 | */ | |
554 | if (!fn) { | |
555 | wake_up_process(data); | |
556 | restart = HRTIMER_NORESTART; | |
557 | } else | |
558 | restart = fn(data); | |
559 | ||
560 | spin_lock_irq(&base->lock); | |
561 | ||
562 | if (restart == HRTIMER_RESTART) | |
563 | enqueue_hrtimer(timer, base); | |
564 | else | |
565 | timer->state = HRTIMER_EXPIRED; | |
566 | } | |
567 | set_curr_timer(base, NULL); | |
568 | spin_unlock_irq(&base->lock); | |
569 | } | |
570 | ||
571 | /* | |
572 | * Called from timer softirq every jiffy, expire hrtimers: | |
573 | */ | |
574 | void hrtimer_run_queues(void) | |
575 | { | |
576 | struct hrtimer_base *base = __get_cpu_var(hrtimer_bases); | |
577 | int i; | |
578 | ||
579 | for (i = 0; i < MAX_HRTIMER_BASES; i++) | |
580 | run_hrtimer_queue(&base[i]); | |
581 | } | |
582 | ||
583 | /* | |
584 | * Functions related to boot-time initialization: | |
585 | */ | |
586 | static void __devinit init_hrtimers_cpu(int cpu) | |
587 | { | |
588 | struct hrtimer_base *base = per_cpu(hrtimer_bases, cpu); | |
589 | int i; | |
590 | ||
591 | for (i = 0; i < MAX_HRTIMER_BASES; i++) { | |
592 | spin_lock_init(&base->lock); | |
593 | INIT_LIST_HEAD(&base->pending); | |
594 | base++; | |
595 | } | |
596 | } | |
597 | ||
598 | #ifdef CONFIG_HOTPLUG_CPU | |
599 | ||
600 | static void migrate_hrtimer_list(struct hrtimer_base *old_base, | |
601 | struct hrtimer_base *new_base) | |
602 | { | |
603 | struct hrtimer *timer; | |
604 | struct rb_node *node; | |
605 | ||
606 | while ((node = rb_first(&old_base->active))) { | |
607 | timer = rb_entry(node, struct hrtimer, node); | |
608 | __remove_hrtimer(timer, old_base); | |
609 | timer->base = new_base; | |
610 | enqueue_hrtimer(timer, new_base); | |
611 | } | |
612 | } | |
613 | ||
614 | static void migrate_hrtimers(int cpu) | |
615 | { | |
616 | struct hrtimer_base *old_base, *new_base; | |
617 | int i; | |
618 | ||
619 | BUG_ON(cpu_online(cpu)); | |
620 | old_base = per_cpu(hrtimer_bases, cpu); | |
621 | new_base = get_cpu_var(hrtimer_bases); | |
622 | ||
623 | local_irq_disable(); | |
624 | ||
625 | for (i = 0; i < MAX_HRTIMER_BASES; i++) { | |
626 | ||
627 | spin_lock(&new_base->lock); | |
628 | spin_lock(&old_base->lock); | |
629 | ||
630 | BUG_ON(old_base->curr_timer); | |
631 | ||
632 | migrate_hrtimer_list(old_base, new_base); | |
633 | ||
634 | spin_unlock(&old_base->lock); | |
635 | spin_unlock(&new_base->lock); | |
636 | old_base++; | |
637 | new_base++; | |
638 | } | |
639 | ||
640 | local_irq_enable(); | |
641 | put_cpu_var(hrtimer_bases); | |
642 | } | |
643 | #endif /* CONFIG_HOTPLUG_CPU */ | |
644 | ||
645 | static int __devinit hrtimer_cpu_notify(struct notifier_block *self, | |
646 | unsigned long action, void *hcpu) | |
647 | { | |
648 | long cpu = (long)hcpu; | |
649 | ||
650 | switch (action) { | |
651 | ||
652 | case CPU_UP_PREPARE: | |
653 | init_hrtimers_cpu(cpu); | |
654 | break; | |
655 | ||
656 | #ifdef CONFIG_HOTPLUG_CPU | |
657 | case CPU_DEAD: | |
658 | migrate_hrtimers(cpu); | |
659 | break; | |
660 | #endif | |
661 | ||
662 | default: | |
663 | break; | |
664 | } | |
665 | ||
666 | return NOTIFY_OK; | |
667 | } | |
668 | ||
669 | static struct notifier_block __devinitdata hrtimers_nb = { | |
670 | .notifier_call = hrtimer_cpu_notify, | |
671 | }; | |
672 | ||
673 | void __init hrtimers_init(void) | |
674 | { | |
675 | hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE, | |
676 | (void *)(long)smp_processor_id()); | |
677 | register_cpu_notifier(&hrtimers_nb); | |
678 | } | |
679 |