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Source at commit ec7cab4cbb721bff91ec924ec691efd8daf36579 created 12 years 8 months ago. By Maarten ter Huurne, MIPS: JZ4740: A320: Updated quickstart documentation. | |
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1 | /* |
2 | * linux/kernel/hrtimer.c |
3 | * |
4 | * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de> |
5 | * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar |
6 | * Copyright(C) 2006-2007 Timesys Corp., Thomas Gleixner |
7 | * |
8 | * High-resolution kernel timers |
9 | * |
10 | * In contrast to the low-resolution timeout API implemented in |
11 | * kernel/timer.c, hrtimers provide finer resolution and accuracy |
12 | * depending on system configuration and capabilities. |
13 | * |
14 | * These timers are currently used for: |
15 | * - itimers |
16 | * - POSIX timers |
17 | * - nanosleep |
18 | * - precise in-kernel timing |
19 | * |
20 | * Started by: Thomas Gleixner and Ingo Molnar |
21 | * |
22 | * Credits: |
23 | * based on kernel/timer.c |
24 | * |
25 | * Help, testing, suggestions, bugfixes, improvements were |
26 | * provided by: |
27 | * |
28 | * George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel |
29 | * et. al. |
30 | * |
31 | * For licencing details see kernel-base/COPYING |
32 | */ |
33 | |
34 | #include <linux/cpu.h> |
35 | #include <linux/module.h> |
36 | #include <linux/percpu.h> |
37 | #include <linux/hrtimer.h> |
38 | #include <linux/notifier.h> |
39 | #include <linux/syscalls.h> |
40 | #include <linux/kallsyms.h> |
41 | #include <linux/interrupt.h> |
42 | #include <linux/tick.h> |
43 | #include <linux/seq_file.h> |
44 | #include <linux/err.h> |
45 | #include <linux/debugobjects.h> |
46 | #include <linux/sched.h> |
47 | #include <linux/timer.h> |
48 | |
49 | #include <asm/uaccess.h> |
50 | |
51 | #include <trace/events/timer.h> |
52 | |
53 | /* |
54 | * The timer bases: |
55 | * |
56 | * There are more clockids then hrtimer bases. Thus, we index |
57 | * into the timer bases by the hrtimer_base_type enum. When trying |
58 | * to reach a base using a clockid, hrtimer_clockid_to_base() |
59 | * is used to convert from clockid to the proper hrtimer_base_type. |
60 | */ |
61 | DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) = |
62 | { |
63 | |
64 | .clock_base = |
65 | { |
66 | { |
67 | .index = CLOCK_REALTIME, |
68 | .get_time = &ktime_get_real, |
69 | .resolution = KTIME_LOW_RES, |
70 | }, |
71 | { |
72 | .index = CLOCK_MONOTONIC, |
73 | .get_time = &ktime_get, |
74 | .resolution = KTIME_LOW_RES, |
75 | }, |
76 | { |
77 | .index = CLOCK_BOOTTIME, |
78 | .get_time = &ktime_get_boottime, |
79 | .resolution = KTIME_LOW_RES, |
80 | }, |
81 | } |
82 | }; |
83 | |
84 | static int hrtimer_clock_to_base_table[MAX_CLOCKS] = { |
85 | [CLOCK_REALTIME] = HRTIMER_BASE_REALTIME, |
86 | [CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC, |
87 | [CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME, |
88 | }; |
89 | |
90 | static inline int hrtimer_clockid_to_base(clockid_t clock_id) |
91 | { |
92 | return hrtimer_clock_to_base_table[clock_id]; |
93 | } |
94 | |
95 | |
96 | /* |
97 | * Get the coarse grained time at the softirq based on xtime and |
98 | * wall_to_monotonic. |
99 | */ |
100 | static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base) |
101 | { |
102 | ktime_t xtim, mono, boot; |
103 | struct timespec xts, tom, slp; |
104 | |
105 | get_xtime_and_monotonic_and_sleep_offset(&xts, &tom, &slp); |
106 | |
107 | xtim = timespec_to_ktime(xts); |
108 | mono = ktime_add(xtim, timespec_to_ktime(tom)); |
109 | boot = ktime_add(mono, timespec_to_ktime(slp)); |
110 | base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim; |
111 | base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono; |
112 | base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot; |
113 | } |
114 | |
115 | /* |
116 | * Functions and macros which are different for UP/SMP systems are kept in a |
117 | * single place |
118 | */ |
119 | #ifdef CONFIG_SMP |
120 | |
121 | /* |
122 | * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock |
123 | * means that all timers which are tied to this base via timer->base are |
124 | * locked, and the base itself is locked too. |
125 | * |
126 | * So __run_timers/migrate_timers can safely modify all timers which could |
127 | * be found on the lists/queues. |
128 | * |
129 | * When the timer's base is locked, and the timer removed from list, it is |
130 | * possible to set timer->base = NULL and drop the lock: the timer remains |
131 | * locked. |
132 | */ |
133 | static |
134 | struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer, |
135 | unsigned long *flags) |
136 | { |
137 | struct hrtimer_clock_base *base; |
138 | |
139 | for (;;) { |
140 | base = timer->base; |
141 | if (likely(base != NULL)) { |
142 | raw_spin_lock_irqsave(&base->cpu_base->lock, *flags); |
143 | if (likely(base == timer->base)) |
144 | return base; |
145 | /* The timer has migrated to another CPU: */ |
146 | raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags); |
147 | } |
148 | cpu_relax(); |
149 | } |
150 | } |
151 | |
152 | |
153 | /* |
154 | * Get the preferred target CPU for NOHZ |
155 | */ |
156 | static int hrtimer_get_target(int this_cpu, int pinned) |
157 | { |
158 | #ifdef CONFIG_NO_HZ |
159 | if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu)) |
160 | return get_nohz_timer_target(); |
161 | #endif |
162 | return this_cpu; |
163 | } |
164 | |
165 | /* |
166 | * With HIGHRES=y we do not migrate the timer when it is expiring |
167 | * before the next event on the target cpu because we cannot reprogram |
168 | * the target cpu hardware and we would cause it to fire late. |
169 | * |
170 | * Called with cpu_base->lock of target cpu held. |
171 | */ |
172 | static int |
173 | hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base) |
174 | { |
175 | #ifdef CONFIG_HIGH_RES_TIMERS |
176 | ktime_t expires; |
177 | |
178 | if (!new_base->cpu_base->hres_active) |
179 | return 0; |
180 | |
181 | expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset); |
182 | return expires.tv64 <= new_base->cpu_base->expires_next.tv64; |
183 | #else |
184 | return 0; |
185 | #endif |
186 | } |
187 | |
188 | /* |
189 | * Switch the timer base to the current CPU when possible. |
190 | */ |
191 | static inline struct hrtimer_clock_base * |
192 | switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base, |
193 | int pinned) |
194 | { |
195 | struct hrtimer_clock_base *new_base; |
196 | struct hrtimer_cpu_base *new_cpu_base; |
197 | int this_cpu = smp_processor_id(); |
198 | int cpu = hrtimer_get_target(this_cpu, pinned); |
199 | int basenum = hrtimer_clockid_to_base(base->index); |
200 | |
201 | again: |
202 | new_cpu_base = &per_cpu(hrtimer_bases, cpu); |
203 | new_base = &new_cpu_base->clock_base[basenum]; |
204 | |
205 | if (base != new_base) { |
206 | /* |
207 | * We are trying to move timer to new_base. |
208 | * However we can't change timer's base while it is running, |
209 | * so we keep it on the same CPU. No hassle vs. reprogramming |
210 | * the event source in the high resolution case. The softirq |
211 | * code will take care of this when the timer function has |
212 | * completed. There is no conflict as we hold the lock until |
213 | * the timer is enqueued. |
214 | */ |
215 | if (unlikely(hrtimer_callback_running(timer))) |
216 | return base; |
217 | |
218 | /* See the comment in lock_timer_base() */ |
219 | timer->base = NULL; |
220 | raw_spin_unlock(&base->cpu_base->lock); |
221 | raw_spin_lock(&new_base->cpu_base->lock); |
222 | |
223 | if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) { |
224 | cpu = this_cpu; |
225 | raw_spin_unlock(&new_base->cpu_base->lock); |
226 | raw_spin_lock(&base->cpu_base->lock); |
227 | timer->base = base; |
228 | goto again; |
229 | } |
230 | timer->base = new_base; |
231 | } |
232 | return new_base; |
233 | } |
234 | |
235 | #else /* CONFIG_SMP */ |
236 | |
237 | static inline struct hrtimer_clock_base * |
238 | lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) |
239 | { |
240 | struct hrtimer_clock_base *base = timer->base; |
241 | |
242 | raw_spin_lock_irqsave(&base->cpu_base->lock, *flags); |
243 | |
244 | return base; |
245 | } |
246 | |
247 | # define switch_hrtimer_base(t, b, p) (b) |
248 | |
249 | #endif /* !CONFIG_SMP */ |
250 | |
251 | /* |
252 | * Functions for the union type storage format of ktime_t which are |
253 | * too large for inlining: |
254 | */ |
255 | #if BITS_PER_LONG < 64 |
256 | # ifndef CONFIG_KTIME_SCALAR |
257 | /** |
258 | * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable |
259 | * @kt: addend |
260 | * @nsec: the scalar nsec value to add |
261 | * |
262 | * Returns the sum of kt and nsec in ktime_t format |
263 | */ |
264 | ktime_t ktime_add_ns(const ktime_t kt, u64 nsec) |
265 | { |
266 | ktime_t tmp; |
267 | |
268 | if (likely(nsec < NSEC_PER_SEC)) { |
269 | tmp.tv64 = nsec; |
270 | } else { |
271 | unsigned long rem = do_div(nsec, NSEC_PER_SEC); |
272 | |
273 | tmp = ktime_set((long)nsec, rem); |
274 | } |
275 | |
276 | return ktime_add(kt, tmp); |
277 | } |
278 | |
279 | EXPORT_SYMBOL_GPL(ktime_add_ns); |
280 | |
281 | /** |
282 | * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable |
283 | * @kt: minuend |
284 | * @nsec: the scalar nsec value to subtract |
285 | * |
286 | * Returns the subtraction of @nsec from @kt in ktime_t format |
287 | */ |
288 | ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec) |
289 | { |
290 | ktime_t tmp; |
291 | |
292 | if (likely(nsec < NSEC_PER_SEC)) { |
293 | tmp.tv64 = nsec; |
294 | } else { |
295 | unsigned long rem = do_div(nsec, NSEC_PER_SEC); |
296 | |
297 | tmp = ktime_set((long)nsec, rem); |
298 | } |
299 | |
300 | return ktime_sub(kt, tmp); |
301 | } |
302 | |
303 | EXPORT_SYMBOL_GPL(ktime_sub_ns); |
304 | # endif /* !CONFIG_KTIME_SCALAR */ |
305 | |
306 | /* |
307 | * Divide a ktime value by a nanosecond value |
308 | */ |
309 | u64 ktime_divns(const ktime_t kt, s64 div) |
310 | { |
311 | u64 dclc; |
312 | int sft = 0; |
313 | |
314 | dclc = ktime_to_ns(kt); |
315 | /* Make sure the divisor is less than 2^32: */ |
316 | while (div >> 32) { |
317 | sft++; |
318 | div >>= 1; |
319 | } |
320 | dclc >>= sft; |
321 | do_div(dclc, (unsigned long) div); |
322 | |
323 | return dclc; |
324 | } |
325 | #endif /* BITS_PER_LONG >= 64 */ |
326 | |
327 | /* |
328 | * Add two ktime values and do a safety check for overflow: |
329 | */ |
330 | ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs) |
331 | { |
332 | ktime_t res = ktime_add(lhs, rhs); |
333 | |
334 | /* |
335 | * We use KTIME_SEC_MAX here, the maximum timeout which we can |
336 | * return to user space in a timespec: |
337 | */ |
338 | if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64) |
339 | res = ktime_set(KTIME_SEC_MAX, 0); |
340 | |
341 | return res; |
342 | } |
343 | |
344 | EXPORT_SYMBOL_GPL(ktime_add_safe); |
345 | |
346 | #ifdef CONFIG_DEBUG_OBJECTS_TIMERS |
347 | |
348 | static struct debug_obj_descr hrtimer_debug_descr; |
349 | |
350 | static void *hrtimer_debug_hint(void *addr) |
351 | { |
352 | return ((struct hrtimer *) addr)->function; |
353 | } |
354 | |
355 | /* |
356 | * fixup_init is called when: |
357 | * - an active object is initialized |
358 | */ |
359 | static int hrtimer_fixup_init(void *addr, enum debug_obj_state state) |
360 | { |
361 | struct hrtimer *timer = addr; |
362 | |
363 | switch (state) { |
364 | case ODEBUG_STATE_ACTIVE: |
365 | hrtimer_cancel(timer); |
366 | debug_object_init(timer, &hrtimer_debug_descr); |
367 | return 1; |
368 | default: |
369 | return 0; |
370 | } |
371 | } |
372 | |
373 | /* |
374 | * fixup_activate is called when: |
375 | * - an active object is activated |
376 | * - an unknown object is activated (might be a statically initialized object) |
377 | */ |
378 | static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state) |
379 | { |
380 | switch (state) { |
381 | |
382 | case ODEBUG_STATE_NOTAVAILABLE: |
383 | WARN_ON_ONCE(1); |
384 | return 0; |
385 | |
386 | case ODEBUG_STATE_ACTIVE: |
387 | WARN_ON(1); |
388 | |
389 | default: |
390 | return 0; |
391 | } |
392 | } |
393 | |
394 | /* |
395 | * fixup_free is called when: |
396 | * - an active object is freed |
397 | */ |
398 | static int hrtimer_fixup_free(void *addr, enum debug_obj_state state) |
399 | { |
400 | struct hrtimer *timer = addr; |
401 | |
402 | switch (state) { |
403 | case ODEBUG_STATE_ACTIVE: |
404 | hrtimer_cancel(timer); |
405 | debug_object_free(timer, &hrtimer_debug_descr); |
406 | return 1; |
407 | default: |
408 | return 0; |
409 | } |
410 | } |
411 | |
412 | static struct debug_obj_descr hrtimer_debug_descr = { |
413 | .name = "hrtimer", |
414 | .debug_hint = hrtimer_debug_hint, |
415 | .fixup_init = hrtimer_fixup_init, |
416 | .fixup_activate = hrtimer_fixup_activate, |
417 | .fixup_free = hrtimer_fixup_free, |
418 | }; |
419 | |
420 | static inline void debug_hrtimer_init(struct hrtimer *timer) |
421 | { |
422 | debug_object_init(timer, &hrtimer_debug_descr); |
423 | } |
424 | |
425 | static inline void debug_hrtimer_activate(struct hrtimer *timer) |
426 | { |
427 | debug_object_activate(timer, &hrtimer_debug_descr); |
428 | } |
429 | |
430 | static inline void debug_hrtimer_deactivate(struct hrtimer *timer) |
431 | { |
432 | debug_object_deactivate(timer, &hrtimer_debug_descr); |
433 | } |
434 | |
435 | static inline void debug_hrtimer_free(struct hrtimer *timer) |
436 | { |
437 | debug_object_free(timer, &hrtimer_debug_descr); |
438 | } |
439 | |
440 | static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id, |
441 | enum hrtimer_mode mode); |
442 | |
443 | void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id, |
444 | enum hrtimer_mode mode) |
445 | { |
446 | debug_object_init_on_stack(timer, &hrtimer_debug_descr); |
447 | __hrtimer_init(timer, clock_id, mode); |
448 | } |
449 | EXPORT_SYMBOL_GPL(hrtimer_init_on_stack); |
450 | |
451 | void destroy_hrtimer_on_stack(struct hrtimer *timer) |
452 | { |
453 | debug_object_free(timer, &hrtimer_debug_descr); |
454 | } |
455 | |
456 | #else |
457 | static inline void debug_hrtimer_init(struct hrtimer *timer) { } |
458 | static inline void debug_hrtimer_activate(struct hrtimer *timer) { } |
459 | static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { } |
460 | #endif |
461 | |
462 | static inline void |
463 | debug_init(struct hrtimer *timer, clockid_t clockid, |
464 | enum hrtimer_mode mode) |
465 | { |
466 | debug_hrtimer_init(timer); |
467 | trace_hrtimer_init(timer, clockid, mode); |
468 | } |
469 | |
470 | static inline void debug_activate(struct hrtimer *timer) |
471 | { |
472 | debug_hrtimer_activate(timer); |
473 | trace_hrtimer_start(timer); |
474 | } |
475 | |
476 | static inline void debug_deactivate(struct hrtimer *timer) |
477 | { |
478 | debug_hrtimer_deactivate(timer); |
479 | trace_hrtimer_cancel(timer); |
480 | } |
481 | |
482 | /* High resolution timer related functions */ |
483 | #ifdef CONFIG_HIGH_RES_TIMERS |
484 | |
485 | /* |
486 | * High resolution timer enabled ? |
487 | */ |
488 | static int hrtimer_hres_enabled __read_mostly = 1; |
489 | |
490 | /* |
491 | * Enable / Disable high resolution mode |
492 | */ |
493 | static int __init setup_hrtimer_hres(char *str) |
494 | { |
495 | if (!strcmp(str, "off")) |
496 | hrtimer_hres_enabled = 0; |
497 | else if (!strcmp(str, "on")) |
498 | hrtimer_hres_enabled = 1; |
499 | else |
500 | return 0; |
501 | return 1; |
502 | } |
503 | |
504 | __setup("highres=", setup_hrtimer_hres); |
505 | |
506 | /* |
507 | * hrtimer_high_res_enabled - query, if the highres mode is enabled |
508 | */ |
509 | static inline int hrtimer_is_hres_enabled(void) |
510 | { |
511 | return hrtimer_hres_enabled; |
512 | } |
513 | |
514 | /* |
515 | * Is the high resolution mode active ? |
516 | */ |
517 | static inline int hrtimer_hres_active(void) |
518 | { |
519 | return __this_cpu_read(hrtimer_bases.hres_active); |
520 | } |
521 | |
522 | /* |
523 | * Reprogram the event source with checking both queues for the |
524 | * next event |
525 | * Called with interrupts disabled and base->lock held |
526 | */ |
527 | static void |
528 | hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal) |
529 | { |
530 | int i; |
531 | struct hrtimer_clock_base *base = cpu_base->clock_base; |
532 | ktime_t expires, expires_next; |
533 | |
534 | expires_next.tv64 = KTIME_MAX; |
535 | |
536 | for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) { |
537 | struct hrtimer *timer; |
538 | struct timerqueue_node *next; |
539 | |
540 | next = timerqueue_getnext(&base->active); |
541 | if (!next) |
542 | continue; |
543 | timer = container_of(next, struct hrtimer, node); |
544 | |
545 | expires = ktime_sub(hrtimer_get_expires(timer), base->offset); |
546 | /* |
547 | * clock_was_set() has changed base->offset so the |
548 | * result might be negative. Fix it up to prevent a |
549 | * false positive in clockevents_program_event() |
550 | */ |
551 | if (expires.tv64 < 0) |
552 | expires.tv64 = 0; |
553 | if (expires.tv64 < expires_next.tv64) |
554 | expires_next = expires; |
555 | } |
556 | |
557 | if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64) |
558 | return; |
559 | |
560 | cpu_base->expires_next.tv64 = expires_next.tv64; |
561 | |
562 | if (cpu_base->expires_next.tv64 != KTIME_MAX) |
563 | tick_program_event(cpu_base->expires_next, 1); |
564 | } |
565 | |
566 | /* |
567 | * Shared reprogramming for clock_realtime and clock_monotonic |
568 | * |
569 | * When a timer is enqueued and expires earlier than the already enqueued |
570 | * timers, we have to check, whether it expires earlier than the timer for |
571 | * which the clock event device was armed. |
572 | * |
573 | * Called with interrupts disabled and base->cpu_base.lock held |
574 | */ |
575 | static int hrtimer_reprogram(struct hrtimer *timer, |
576 | struct hrtimer_clock_base *base) |
577 | { |
578 | struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); |
579 | ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset); |
580 | int res; |
581 | |
582 | WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0); |
583 | |
584 | /* |
585 | * When the callback is running, we do not reprogram the clock event |
586 | * device. The timer callback is either running on a different CPU or |
587 | * the callback is executed in the hrtimer_interrupt context. The |
588 | * reprogramming is handled either by the softirq, which called the |
589 | * callback or at the end of the hrtimer_interrupt. |
590 | */ |
591 | if (hrtimer_callback_running(timer)) |
592 | return 0; |
593 | |
594 | /* |
595 | * CLOCK_REALTIME timer might be requested with an absolute |
596 | * expiry time which is less than base->offset. Nothing wrong |
597 | * about that, just avoid to call into the tick code, which |
598 | * has now objections against negative expiry values. |
599 | */ |
600 | if (expires.tv64 < 0) |
601 | return -ETIME; |
602 | |
603 | if (expires.tv64 >= cpu_base->expires_next.tv64) |
604 | return 0; |
605 | |
606 | /* |
607 | * If a hang was detected in the last timer interrupt then we |
608 | * do not schedule a timer which is earlier than the expiry |
609 | * which we enforced in the hang detection. We want the system |
610 | * to make progress. |
611 | */ |
612 | if (cpu_base->hang_detected) |
613 | return 0; |
614 | |
615 | /* |
616 | * Clockevents returns -ETIME, when the event was in the past. |
617 | */ |
618 | res = tick_program_event(expires, 0); |
619 | if (!IS_ERR_VALUE(res)) |
620 | cpu_base->expires_next = expires; |
621 | return res; |
622 | } |
623 | |
624 | |
625 | /* |
626 | * Retrigger next event is called after clock was set |
627 | * |
628 | * Called with interrupts disabled via on_each_cpu() |
629 | */ |
630 | static void retrigger_next_event(void *arg) |
631 | { |
632 | struct hrtimer_cpu_base *base; |
633 | struct timespec realtime_offset, wtm, sleep; |
634 | |
635 | if (!hrtimer_hres_active()) |
636 | return; |
637 | |
638 | get_xtime_and_monotonic_and_sleep_offset(&realtime_offset, &wtm, |
639 | &sleep); |
640 | set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec); |
641 | |
642 | base = &__get_cpu_var(hrtimer_bases); |
643 | |
644 | /* Adjust CLOCK_REALTIME offset */ |
645 | raw_spin_lock(&base->lock); |
646 | base->clock_base[HRTIMER_BASE_REALTIME].offset = |
647 | timespec_to_ktime(realtime_offset); |
648 | base->clock_base[HRTIMER_BASE_BOOTTIME].offset = |
649 | timespec_to_ktime(sleep); |
650 | |
651 | hrtimer_force_reprogram(base, 0); |
652 | raw_spin_unlock(&base->lock); |
653 | } |
654 | |
655 | /* |
656 | * Clock realtime was set |
657 | * |
658 | * Change the offset of the realtime clock vs. the monotonic |
659 | * clock. |
660 | * |
661 | * We might have to reprogram the high resolution timer interrupt. On |
662 | * SMP we call the architecture specific code to retrigger _all_ high |
663 | * resolution timer interrupts. On UP we just disable interrupts and |
664 | * call the high resolution interrupt code. |
665 | */ |
666 | void clock_was_set(void) |
667 | { |
668 | /* Retrigger the CPU local events everywhere */ |
669 | on_each_cpu(retrigger_next_event, NULL, 1); |
670 | } |
671 | |
672 | /* |
673 | * During resume we might have to reprogram the high resolution timer |
674 | * interrupt (on the local CPU): |
675 | */ |
676 | void hres_timers_resume(void) |
677 | { |
678 | WARN_ONCE(!irqs_disabled(), |
679 | KERN_INFO "hres_timers_resume() called with IRQs enabled!"); |
680 | |
681 | retrigger_next_event(NULL); |
682 | } |
683 | |
684 | /* |
685 | * Initialize the high resolution related parts of cpu_base |
686 | */ |
687 | static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) |
688 | { |
689 | base->expires_next.tv64 = KTIME_MAX; |
690 | base->hres_active = 0; |
691 | } |
692 | |
693 | /* |
694 | * When High resolution timers are active, try to reprogram. Note, that in case |
695 | * the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry |
696 | * check happens. The timer gets enqueued into the rbtree. The reprogramming |
697 | * and expiry check is done in the hrtimer_interrupt or in the softirq. |
698 | */ |
699 | static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, |
700 | struct hrtimer_clock_base *base, |
701 | int wakeup) |
702 | { |
703 | if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) { |
704 | if (wakeup) { |
705 | raw_spin_unlock(&base->cpu_base->lock); |
706 | raise_softirq_irqoff(HRTIMER_SOFTIRQ); |
707 | raw_spin_lock(&base->cpu_base->lock); |
708 | } else |
709 | __raise_softirq_irqoff(HRTIMER_SOFTIRQ); |
710 | |
711 | return 1; |
712 | } |
713 | |
714 | return 0; |
715 | } |
716 | |
717 | /* |
718 | * Switch to high resolution mode |
719 | */ |
720 | static int hrtimer_switch_to_hres(void) |
721 | { |
722 | int cpu = smp_processor_id(); |
723 | struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu); |
724 | unsigned long flags; |
725 | |
726 | if (base->hres_active) |
727 | return 1; |
728 | |
729 | local_irq_save(flags); |
730 | |
731 | if (tick_init_highres()) { |
732 | local_irq_restore(flags); |
733 | printk(KERN_WARNING "Could not switch to high resolution " |
734 | "mode on CPU %d\n", cpu); |
735 | return 0; |
736 | } |
737 | base->hres_active = 1; |
738 | base->clock_base[HRTIMER_BASE_REALTIME].resolution = KTIME_HIGH_RES; |
739 | base->clock_base[HRTIMER_BASE_MONOTONIC].resolution = KTIME_HIGH_RES; |
740 | base->clock_base[HRTIMER_BASE_BOOTTIME].resolution = KTIME_HIGH_RES; |
741 | |
742 | tick_setup_sched_timer(); |
743 | |
744 | /* "Retrigger" the interrupt to get things going */ |
745 | retrigger_next_event(NULL); |
746 | local_irq_restore(flags); |
747 | return 1; |
748 | } |
749 | |
750 | #else |
751 | |
752 | static inline int hrtimer_hres_active(void) { return 0; } |
753 | static inline int hrtimer_is_hres_enabled(void) { return 0; } |
754 | static inline int hrtimer_switch_to_hres(void) { return 0; } |
755 | static inline void |
756 | hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { } |
757 | static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, |
758 | struct hrtimer_clock_base *base, |
759 | int wakeup) |
760 | { |
761 | return 0; |
762 | } |
763 | static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { } |
764 | |
765 | #endif /* CONFIG_HIGH_RES_TIMERS */ |
766 | |
767 | static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer) |
768 | { |
769 | #ifdef CONFIG_TIMER_STATS |
770 | if (timer->start_site) |
771 | return; |
772 | timer->start_site = __builtin_return_address(0); |
773 | memcpy(timer->start_comm, current->comm, TASK_COMM_LEN); |
774 | timer->start_pid = current->pid; |
775 | #endif |
776 | } |
777 | |
778 | static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer) |
779 | { |
780 | #ifdef CONFIG_TIMER_STATS |
781 | timer->start_site = NULL; |
782 | #endif |
783 | } |
784 | |
785 | static inline void timer_stats_account_hrtimer(struct hrtimer *timer) |
786 | { |
787 | #ifdef CONFIG_TIMER_STATS |
788 | if (likely(!timer_stats_active)) |
789 | return; |
790 | timer_stats_update_stats(timer, timer->start_pid, timer->start_site, |
791 | timer->function, timer->start_comm, 0); |
792 | #endif |
793 | } |
794 | |
795 | /* |
796 | * Counterpart to lock_hrtimer_base above: |
797 | */ |
798 | static inline |
799 | void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags) |
800 | { |
801 | raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags); |
802 | } |
803 | |
804 | /** |
805 | * hrtimer_forward - forward the timer expiry |
806 | * @timer: hrtimer to forward |
807 | * @now: forward past this time |
808 | * @interval: the interval to forward |
809 | * |
810 | * Forward the timer expiry so it will expire in the future. |
811 | * Returns the number of overruns. |
812 | */ |
813 | u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval) |
814 | { |
815 | u64 orun = 1; |
816 | ktime_t delta; |
817 | |
818 | delta = ktime_sub(now, hrtimer_get_expires(timer)); |
819 | |
820 | if (delta.tv64 < 0) |
821 | return 0; |
822 | |
823 | if (interval.tv64 < timer->base->resolution.tv64) |
824 | interval.tv64 = timer->base->resolution.tv64; |
825 | |
826 | if (unlikely(delta.tv64 >= interval.tv64)) { |
827 | s64 incr = ktime_to_ns(interval); |
828 | |
829 | orun = ktime_divns(delta, incr); |
830 | hrtimer_add_expires_ns(timer, incr * orun); |
831 | if (hrtimer_get_expires_tv64(timer) > now.tv64) |
832 | return orun; |
833 | /* |
834 | * This (and the ktime_add() below) is the |
835 | * correction for exact: |
836 | */ |
837 | orun++; |
838 | } |
839 | hrtimer_add_expires(timer, interval); |
840 | |
841 | return orun; |
842 | } |
843 | EXPORT_SYMBOL_GPL(hrtimer_forward); |
844 | |
845 | /* |
846 | * enqueue_hrtimer - internal function to (re)start a timer |
847 | * |
848 | * The timer is inserted in expiry order. Insertion into the |
849 | * red black tree is O(log(n)). Must hold the base lock. |
850 | * |
851 | * Returns 1 when the new timer is the leftmost timer in the tree. |
852 | */ |
853 | static int enqueue_hrtimer(struct hrtimer *timer, |
854 | struct hrtimer_clock_base *base) |
855 | { |
856 | debug_activate(timer); |
857 | |
858 | timerqueue_add(&base->active, &timer->node); |
859 | |
860 | /* |
861 | * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the |
862 | * state of a possibly running callback. |
863 | */ |
864 | timer->state |= HRTIMER_STATE_ENQUEUED; |
865 | |
866 | return (&timer->node == base->active.next); |
867 | } |
868 | |
869 | /* |
870 | * __remove_hrtimer - internal function to remove a timer |
871 | * |
872 | * Caller must hold the base lock. |
873 | * |
874 | * High resolution timer mode reprograms the clock event device when the |
875 | * timer is the one which expires next. The caller can disable this by setting |
876 | * reprogram to zero. This is useful, when the context does a reprogramming |
877 | * anyway (e.g. timer interrupt) |
878 | */ |
879 | static void __remove_hrtimer(struct hrtimer *timer, |
880 | struct hrtimer_clock_base *base, |
881 | unsigned long newstate, int reprogram) |
882 | { |
883 | if (!(timer->state & HRTIMER_STATE_ENQUEUED)) |
884 | goto out; |
885 | |
886 | if (&timer->node == timerqueue_getnext(&base->active)) { |
887 | #ifdef CONFIG_HIGH_RES_TIMERS |
888 | /* Reprogram the clock event device. if enabled */ |
889 | if (reprogram && hrtimer_hres_active()) { |
890 | ktime_t expires; |
891 | |
892 | expires = ktime_sub(hrtimer_get_expires(timer), |
893 | base->offset); |
894 | if (base->cpu_base->expires_next.tv64 == expires.tv64) |
895 | hrtimer_force_reprogram(base->cpu_base, 1); |
896 | } |
897 | #endif |
898 | } |
899 | timerqueue_del(&base->active, &timer->node); |
900 | out: |
901 | timer->state = newstate; |
902 | } |
903 | |
904 | /* |
905 | * remove hrtimer, called with base lock held |
906 | */ |
907 | static inline int |
908 | remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base) |
909 | { |
910 | if (hrtimer_is_queued(timer)) { |
911 | unsigned long state; |
912 | int reprogram; |
913 | |
914 | /* |
915 | * Remove the timer and force reprogramming when high |
916 | * resolution mode is active and the timer is on the current |
917 | * CPU. If we remove a timer on another CPU, reprogramming is |
918 | * skipped. The interrupt event on this CPU is fired and |
919 | * reprogramming happens in the interrupt handler. This is a |
920 | * rare case and less expensive than a smp call. |
921 | */ |
922 | debug_deactivate(timer); |
923 | timer_stats_hrtimer_clear_start_info(timer); |
924 | reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases); |
925 | /* |
926 | * We must preserve the CALLBACK state flag here, |
927 | * otherwise we could move the timer base in |
928 | * switch_hrtimer_base. |
929 | */ |
930 | state = timer->state & HRTIMER_STATE_CALLBACK; |
931 | __remove_hrtimer(timer, base, state, reprogram); |
932 | return 1; |
933 | } |
934 | return 0; |
935 | } |
936 | |
937 | int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, |
938 | unsigned long delta_ns, const enum hrtimer_mode mode, |
939 | int wakeup) |
940 | { |
941 | struct hrtimer_clock_base *base, *new_base; |
942 | unsigned long flags; |
943 | int ret, leftmost; |
944 | |
945 | base = lock_hrtimer_base(timer, &flags); |
946 | |
947 | /* Remove an active timer from the queue: */ |
948 | ret = remove_hrtimer(timer, base); |
949 | |
950 | /* Switch the timer base, if necessary: */ |
951 | new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED); |
952 | |
953 | if (mode & HRTIMER_MODE_REL) { |
954 | tim = ktime_add_safe(tim, new_base->get_time()); |
955 | /* |
956 | * CONFIG_TIME_LOW_RES is a temporary way for architectures |
957 | * to signal that they simply return xtime in |
958 | * do_gettimeoffset(). In this case we want to round up by |
959 | * resolution when starting a relative timer, to avoid short |
960 | * timeouts. This will go away with the GTOD framework. |
961 | */ |
962 | #ifdef CONFIG_TIME_LOW_RES |
963 | tim = ktime_add_safe(tim, base->resolution); |
964 | #endif |
965 | } |
966 | |
967 | hrtimer_set_expires_range_ns(timer, tim, delta_ns); |
968 | |
969 | timer_stats_hrtimer_set_start_info(timer); |
970 | |
971 | leftmost = enqueue_hrtimer(timer, new_base); |
972 | |
973 | /* |
974 | * Only allow reprogramming if the new base is on this CPU. |
975 | * (it might still be on another CPU if the timer was pending) |
976 | * |
977 | * XXX send_remote_softirq() ? |
978 | */ |
979 | if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases)) |
980 | hrtimer_enqueue_reprogram(timer, new_base, wakeup); |
981 | |
982 | unlock_hrtimer_base(timer, &flags); |
983 | |
984 | return ret; |
985 | } |
986 | |
987 | /** |
988 | * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU |
989 | * @timer: the timer to be added |
990 | * @tim: expiry time |
991 | * @delta_ns: "slack" range for the timer |
992 | * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL) |
993 | * |
994 | * Returns: |
995 | * 0 on success |
996 | * 1 when the timer was active |
997 | */ |
998 | int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, |
999 | unsigned long delta_ns, const enum hrtimer_mode mode) |
1000 | { |
1001 | return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1); |
1002 | } |
1003 | EXPORT_SYMBOL_GPL(hrtimer_start_range_ns); |
1004 | |
1005 | /** |
1006 | * hrtimer_start - (re)start an hrtimer on the current CPU |
1007 | * @timer: the timer to be added |
1008 | * @tim: expiry time |
1009 | * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL) |
1010 | * |
1011 | * Returns: |
1012 | * 0 on success |
1013 | * 1 when the timer was active |
1014 | */ |
1015 | int |
1016 | hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) |
1017 | { |
1018 | return __hrtimer_start_range_ns(timer, tim, 0, mode, 1); |
1019 | } |
1020 | EXPORT_SYMBOL_GPL(hrtimer_start); |
1021 | |
1022 | |
1023 | /** |
1024 | * hrtimer_try_to_cancel - try to deactivate a timer |
1025 | * @timer: hrtimer to stop |
1026 | * |
1027 | * Returns: |
1028 | * 0 when the timer was not active |
1029 | * 1 when the timer was active |
1030 | * -1 when the timer is currently excuting the callback function and |
1031 | * cannot be stopped |
1032 | */ |
1033 | int hrtimer_try_to_cancel(struct hrtimer *timer) |
1034 | { |
1035 | struct hrtimer_clock_base *base; |
1036 | unsigned long flags; |
1037 | int ret = -1; |
1038 | |
1039 | base = lock_hrtimer_base(timer, &flags); |
1040 | |
1041 | if (!hrtimer_callback_running(timer)) |
1042 | ret = remove_hrtimer(timer, base); |
1043 | |
1044 | unlock_hrtimer_base(timer, &flags); |
1045 | |
1046 | return ret; |
1047 | |
1048 | } |
1049 | EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel); |
1050 | |
1051 | /** |
1052 | * hrtimer_cancel - cancel a timer and wait for the handler to finish. |
1053 | * @timer: the timer to be cancelled |
1054 | * |
1055 | * Returns: |
1056 | * 0 when the timer was not active |
1057 | * 1 when the timer was active |
1058 | */ |
1059 | int hrtimer_cancel(struct hrtimer *timer) |
1060 | { |
1061 | for (;;) { |
1062 | int ret = hrtimer_try_to_cancel(timer); |
1063 | |
1064 | if (ret >= 0) |
1065 | return ret; |
1066 | cpu_relax(); |
1067 | } |
1068 | } |
1069 | EXPORT_SYMBOL_GPL(hrtimer_cancel); |
1070 | |
1071 | /** |
1072 | * hrtimer_get_remaining - get remaining time for the timer |
1073 | * @timer: the timer to read |
1074 | */ |
1075 | ktime_t hrtimer_get_remaining(const struct hrtimer *timer) |
1076 | { |
1077 | unsigned long flags; |
1078 | ktime_t rem; |
1079 | |
1080 | lock_hrtimer_base(timer, &flags); |
1081 | rem = hrtimer_expires_remaining(timer); |
1082 | unlock_hrtimer_base(timer, &flags); |
1083 | |
1084 | return rem; |
1085 | } |
1086 | EXPORT_SYMBOL_GPL(hrtimer_get_remaining); |
1087 | |
1088 | #ifdef CONFIG_NO_HZ |
1089 | /** |
1090 | * hrtimer_get_next_event - get the time until next expiry event |
1091 | * |
1092 | * Returns the delta to the next expiry event or KTIME_MAX if no timer |
1093 | * is pending. |
1094 | */ |
1095 | ktime_t hrtimer_get_next_event(void) |
1096 | { |
1097 | struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); |
1098 | struct hrtimer_clock_base *base = cpu_base->clock_base; |
1099 | ktime_t delta, mindelta = { .tv64 = KTIME_MAX }; |
1100 | unsigned long flags; |
1101 | int i; |
1102 | |
1103 | raw_spin_lock_irqsave(&cpu_base->lock, flags); |
1104 | |
1105 | if (!hrtimer_hres_active()) { |
1106 | for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) { |
1107 | struct hrtimer *timer; |
1108 | struct timerqueue_node *next; |
1109 | |
1110 | next = timerqueue_getnext(&base->active); |
1111 | if (!next) |
1112 | continue; |
1113 | |
1114 | timer = container_of(next, struct hrtimer, node); |
1115 | delta.tv64 = hrtimer_get_expires_tv64(timer); |
1116 | delta = ktime_sub(delta, base->get_time()); |
1117 | if (delta.tv64 < mindelta.tv64) |
1118 | mindelta.tv64 = delta.tv64; |
1119 | } |
1120 | } |
1121 | |
1122 | raw_spin_unlock_irqrestore(&cpu_base->lock, flags); |
1123 | |
1124 | if (mindelta.tv64 < 0) |
1125 | mindelta.tv64 = 0; |
1126 | return mindelta; |
1127 | } |
1128 | #endif |
1129 | |
1130 | static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id, |
1131 | enum hrtimer_mode mode) |
1132 | { |
1133 | struct hrtimer_cpu_base *cpu_base; |
1134 | int base; |
1135 | |
1136 | memset(timer, 0, sizeof(struct hrtimer)); |
1137 | |
1138 | cpu_base = &__raw_get_cpu_var(hrtimer_bases); |
1139 | |
1140 | if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS) |
1141 | clock_id = CLOCK_MONOTONIC; |
1142 | |
1143 | base = hrtimer_clockid_to_base(clock_id); |
1144 | timer->base = &cpu_base->clock_base[base]; |
1145 | timerqueue_init(&timer->node); |
1146 | |
1147 | #ifdef CONFIG_TIMER_STATS |
1148 | timer->start_site = NULL; |
1149 | timer->start_pid = -1; |
1150 | memset(timer->start_comm, 0, TASK_COMM_LEN); |
1151 | #endif |
1152 | } |
1153 | |
1154 | /** |
1155 | * hrtimer_init - initialize a timer to the given clock |
1156 | * @timer: the timer to be initialized |
1157 | * @clock_id: the clock to be used |
1158 | * @mode: timer mode abs/rel |
1159 | */ |
1160 | void hrtimer_init(struct hrtimer *timer, clockid_t clock_id, |
1161 | enum hrtimer_mode mode) |
1162 | { |
1163 | debug_init(timer, clock_id, mode); |
1164 | __hrtimer_init(timer, clock_id, mode); |
1165 | } |
1166 | EXPORT_SYMBOL_GPL(hrtimer_init); |
1167 | |
1168 | /** |
1169 | * hrtimer_get_res - get the timer resolution for a clock |
1170 | * @which_clock: which clock to query |
1171 | * @tp: pointer to timespec variable to store the resolution |
1172 | * |
1173 | * Store the resolution of the clock selected by @which_clock in the |
1174 | * variable pointed to by @tp. |
1175 | */ |
1176 | int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp) |
1177 | { |
1178 | struct hrtimer_cpu_base *cpu_base; |
1179 | int base = hrtimer_clockid_to_base(which_clock); |
1180 | |
1181 | cpu_base = &__raw_get_cpu_var(hrtimer_bases); |
1182 | *tp = ktime_to_timespec(cpu_base->clock_base[base].resolution); |
1183 | |
1184 | return 0; |
1185 | } |
1186 | EXPORT_SYMBOL_GPL(hrtimer_get_res); |
1187 | |
1188 | static void __run_hrtimer(struct hrtimer *timer, ktime_t *now) |
1189 | { |
1190 | struct hrtimer_clock_base *base = timer->base; |
1191 | struct hrtimer_cpu_base *cpu_base = base->cpu_base; |
1192 | enum hrtimer_restart (*fn)(struct hrtimer *); |
1193 | int restart; |
1194 | |
1195 | WARN_ON(!irqs_disabled()); |
1196 | |
1197 | debug_deactivate(timer); |
1198 | __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0); |
1199 | timer_stats_account_hrtimer(timer); |
1200 | fn = timer->function; |
1201 | |
1202 | /* |
1203 | * Because we run timers from hardirq context, there is no chance |
1204 | * they get migrated to another cpu, therefore its safe to unlock |
1205 | * the timer base. |
1206 | */ |
1207 | raw_spin_unlock(&cpu_base->lock); |
1208 | trace_hrtimer_expire_entry(timer, now); |
1209 | restart = fn(timer); |
1210 | trace_hrtimer_expire_exit(timer); |
1211 | raw_spin_lock(&cpu_base->lock); |
1212 | |
1213 | /* |
1214 | * Note: We clear the CALLBACK bit after enqueue_hrtimer and |
1215 | * we do not reprogramm the event hardware. Happens either in |
1216 | * hrtimer_start_range_ns() or in hrtimer_interrupt() |
1217 | */ |
1218 | if (restart != HRTIMER_NORESTART) { |
1219 | BUG_ON(timer->state != HRTIMER_STATE_CALLBACK); |
1220 | enqueue_hrtimer(timer, base); |
1221 | } |
1222 | |
1223 | WARN_ON_ONCE(!(timer->state & HRTIMER_STATE_CALLBACK)); |
1224 | |
1225 | timer->state &= ~HRTIMER_STATE_CALLBACK; |
1226 | } |
1227 | |
1228 | #ifdef CONFIG_HIGH_RES_TIMERS |
1229 | |
1230 | /* |
1231 | * High resolution timer interrupt |
1232 | * Called with interrupts disabled |
1233 | */ |
1234 | void hrtimer_interrupt(struct clock_event_device *dev) |
1235 | { |
1236 | struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); |
1237 | struct hrtimer_clock_base *base; |
1238 | ktime_t expires_next, now, entry_time, delta; |
1239 | int i, retries = 0; |
1240 | |
1241 | BUG_ON(!cpu_base->hres_active); |
1242 | cpu_base->nr_events++; |
1243 | dev->next_event.tv64 = KTIME_MAX; |
1244 | |
1245 | entry_time = now = ktime_get(); |
1246 | retry: |
1247 | expires_next.tv64 = KTIME_MAX; |
1248 | |
1249 | raw_spin_lock(&cpu_base->lock); |
1250 | /* |
1251 | * We set expires_next to KTIME_MAX here with cpu_base->lock |
1252 | * held to prevent that a timer is enqueued in our queue via |
1253 | * the migration code. This does not affect enqueueing of |
1254 | * timers which run their callback and need to be requeued on |
1255 | * this CPU. |
1256 | */ |
1257 | cpu_base->expires_next.tv64 = KTIME_MAX; |
1258 | |
1259 | base = cpu_base->clock_base; |
1260 | |
1261 | for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) { |
1262 | ktime_t basenow; |
1263 | struct timerqueue_node *node; |
1264 | |
1265 | basenow = ktime_add(now, base->offset); |
1266 | |
1267 | while ((node = timerqueue_getnext(&base->active))) { |
1268 | struct hrtimer *timer; |
1269 | |
1270 | timer = container_of(node, struct hrtimer, node); |
1271 | |
1272 | /* |
1273 | * The immediate goal for using the softexpires is |
1274 | * minimizing wakeups, not running timers at the |
1275 | * earliest interrupt after their soft expiration. |
1276 | * This allows us to avoid using a Priority Search |
1277 | * Tree, which can answer a stabbing querry for |
1278 | * overlapping intervals and instead use the simple |
1279 | * BST we already have. |
1280 | * We don't add extra wakeups by delaying timers that |
1281 | * are right-of a not yet expired timer, because that |
1282 | * timer will have to trigger a wakeup anyway. |
1283 | */ |
1284 | |
1285 | if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer)) { |
1286 | ktime_t expires; |
1287 | |
1288 | expires = ktime_sub(hrtimer_get_expires(timer), |
1289 | base->offset); |
1290 | if (expires.tv64 < expires_next.tv64) |
1291 | expires_next = expires; |
1292 | break; |
1293 | } |
1294 | |
1295 | __run_hrtimer(timer, &basenow); |
1296 | } |
1297 | base++; |
1298 | } |
1299 | |
1300 | /* |
1301 | * Store the new expiry value so the migration code can verify |
1302 | * against it. |
1303 | */ |
1304 | cpu_base->expires_next = expires_next; |
1305 | raw_spin_unlock(&cpu_base->lock); |
1306 | |
1307 | /* Reprogramming necessary ? */ |
1308 | if (expires_next.tv64 == KTIME_MAX || |
1309 | !tick_program_event(expires_next, 0)) { |
1310 | cpu_base->hang_detected = 0; |
1311 | return; |
1312 | } |
1313 | |
1314 | /* |
1315 | * The next timer was already expired due to: |
1316 | * - tracing |
1317 | * - long lasting callbacks |
1318 | * - being scheduled away when running in a VM |
1319 | * |
1320 | * We need to prevent that we loop forever in the hrtimer |
1321 | * interrupt routine. We give it 3 attempts to avoid |
1322 | * overreacting on some spurious event. |
1323 | */ |
1324 | now = ktime_get(); |
1325 | cpu_base->nr_retries++; |
1326 | if (++retries < 3) |
1327 | goto retry; |
1328 | /* |
1329 | * Give the system a chance to do something else than looping |
1330 | * here. We stored the entry time, so we know exactly how long |
1331 | * we spent here. We schedule the next event this amount of |
1332 | * time away. |
1333 | */ |
1334 | cpu_base->nr_hangs++; |
1335 | cpu_base->hang_detected = 1; |
1336 | delta = ktime_sub(now, entry_time); |
1337 | if (delta.tv64 > cpu_base->max_hang_time.tv64) |
1338 | cpu_base->max_hang_time = delta; |
1339 | /* |
1340 | * Limit it to a sensible value as we enforce a longer |
1341 | * delay. Give the CPU at least 100ms to catch up. |
1342 | */ |
1343 | if (delta.tv64 > 100 * NSEC_PER_MSEC) |
1344 | expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC); |
1345 | else |
1346 | expires_next = ktime_add(now, delta); |
1347 | tick_program_event(expires_next, 1); |
1348 | printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n", |
1349 | ktime_to_ns(delta)); |
1350 | } |
1351 | |
1352 | /* |
1353 | * local version of hrtimer_peek_ahead_timers() called with interrupts |
1354 | * disabled. |
1355 | */ |
1356 | static void __hrtimer_peek_ahead_timers(void) |
1357 | { |
1358 | struct tick_device *td; |
1359 | |
1360 | if (!hrtimer_hres_active()) |
1361 | return; |
1362 | |
1363 | td = &__get_cpu_var(tick_cpu_device); |
1364 | if (td && td->evtdev) |
1365 | hrtimer_interrupt(td->evtdev); |
1366 | } |
1367 | |
1368 | /** |
1369 | * hrtimer_peek_ahead_timers -- run soft-expired timers now |
1370 | * |
1371 | * hrtimer_peek_ahead_timers will peek at the timer queue of |
1372 | * the current cpu and check if there are any timers for which |
1373 | * the soft expires time has passed. If any such timers exist, |
1374 | * they are run immediately and then removed from the timer queue. |
1375 | * |
1376 | */ |
1377 | void hrtimer_peek_ahead_timers(void) |
1378 | { |
1379 | unsigned long flags; |
1380 | |
1381 | local_irq_save(flags); |
1382 | __hrtimer_peek_ahead_timers(); |
1383 | local_irq_restore(flags); |
1384 | } |
1385 | |
1386 | static void run_hrtimer_softirq(struct softirq_action *h) |
1387 | { |
1388 | hrtimer_peek_ahead_timers(); |
1389 | } |
1390 | |
1391 | #else /* CONFIG_HIGH_RES_TIMERS */ |
1392 | |
1393 | static inline void __hrtimer_peek_ahead_timers(void) { } |
1394 | |
1395 | #endif /* !CONFIG_HIGH_RES_TIMERS */ |
1396 | |
1397 | /* |
1398 | * Called from timer softirq every jiffy, expire hrtimers: |
1399 | * |
1400 | * For HRT its the fall back code to run the softirq in the timer |
1401 | * softirq context in case the hrtimer initialization failed or has |
1402 | * not been done yet. |
1403 | */ |
1404 | void hrtimer_run_pending(void) |
1405 | { |
1406 | if (hrtimer_hres_active()) |
1407 | return; |
1408 | |
1409 | /* |
1410 | * This _is_ ugly: We have to check in the softirq context, |
1411 | * whether we can switch to highres and / or nohz mode. The |
1412 | * clocksource switch happens in the timer interrupt with |
1413 | * xtime_lock held. Notification from there only sets the |
1414 | * check bit in the tick_oneshot code, otherwise we might |
1415 | * deadlock vs. xtime_lock. |
1416 | */ |
1417 | if (tick_check_oneshot_change(!hrtimer_is_hres_enabled())) |
1418 | hrtimer_switch_to_hres(); |
1419 | } |
1420 | |
1421 | /* |
1422 | * Called from hardirq context every jiffy |
1423 | */ |
1424 | void hrtimer_run_queues(void) |
1425 | { |
1426 | struct timerqueue_node *node; |
1427 | struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); |
1428 | struct hrtimer_clock_base *base; |
1429 | int index, gettime = 1; |
1430 | |
1431 | if (hrtimer_hres_active()) |
1432 | return; |
1433 | |
1434 | for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) { |
1435 | base = &cpu_base->clock_base[index]; |
1436 | if (!timerqueue_getnext(&base->active)) |
1437 | continue; |
1438 | |
1439 | if (gettime) { |
1440 | hrtimer_get_softirq_time(cpu_base); |
1441 | gettime = 0; |
1442 | } |
1443 | |
1444 | raw_spin_lock(&cpu_base->lock); |
1445 | |
1446 | while ((node = timerqueue_getnext(&base->active))) { |
1447 | struct hrtimer *timer; |
1448 | |
1449 | timer = container_of(node, struct hrtimer, node); |
1450 | if (base->softirq_time.tv64 <= |
1451 | hrtimer_get_expires_tv64(timer)) |
1452 | break; |
1453 | |
1454 | __run_hrtimer(timer, &base->softirq_time); |
1455 | } |
1456 | raw_spin_unlock(&cpu_base->lock); |
1457 | } |
1458 | } |
1459 | |
1460 | /* |
1461 | * Sleep related functions: |
1462 | */ |
1463 | static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer) |
1464 | { |
1465 | struct hrtimer_sleeper *t = |
1466 | container_of(timer, struct hrtimer_sleeper, timer); |
1467 | struct task_struct *task = t->task; |
1468 | |
1469 | t->task = NULL; |
1470 | if (task) |
1471 | wake_up_process(task); |
1472 | |
1473 | return HRTIMER_NORESTART; |
1474 | } |
1475 | |
1476 | void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task) |
1477 | { |
1478 | sl->timer.function = hrtimer_wakeup; |
1479 | sl->task = task; |
1480 | } |
1481 | EXPORT_SYMBOL_GPL(hrtimer_init_sleeper); |
1482 | |
1483 | static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode) |
1484 | { |
1485 | hrtimer_init_sleeper(t, current); |
1486 | |
1487 | do { |
1488 | set_current_state(TASK_INTERRUPTIBLE); |
1489 | hrtimer_start_expires(&t->timer, mode); |
1490 | if (!hrtimer_active(&t->timer)) |
1491 | t->task = NULL; |
1492 | |
1493 | if (likely(t->task)) |
1494 | schedule(); |
1495 | |
1496 | hrtimer_cancel(&t->timer); |
1497 | mode = HRTIMER_MODE_ABS; |
1498 | |
1499 | } while (t->task && !signal_pending(current)); |
1500 | |
1501 | __set_current_state(TASK_RUNNING); |
1502 | |
1503 | return t->task == NULL; |
1504 | } |
1505 | |
1506 | static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp) |
1507 | { |
1508 | struct timespec rmt; |
1509 | ktime_t rem; |
1510 | |
1511 | rem = hrtimer_expires_remaining(timer); |
1512 | if (rem.tv64 <= 0) |
1513 | return 0; |
1514 | rmt = ktime_to_timespec(rem); |
1515 | |
1516 | if (copy_to_user(rmtp, &rmt, sizeof(*rmtp))) |
1517 | return -EFAULT; |
1518 | |
1519 | return 1; |
1520 | } |
1521 | |
1522 | long __sched hrtimer_nanosleep_restart(struct restart_block *restart) |
1523 | { |
1524 | struct hrtimer_sleeper t; |
1525 | struct timespec __user *rmtp; |
1526 | int ret = 0; |
1527 | |
1528 | hrtimer_init_on_stack(&t.timer, restart->nanosleep.index, |
1529 | HRTIMER_MODE_ABS); |
1530 | hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires); |
1531 | |
1532 | if (do_nanosleep(&t, HRTIMER_MODE_ABS)) |
1533 | goto out; |
1534 | |
1535 | rmtp = restart->nanosleep.rmtp; |
1536 | if (rmtp) { |
1537 | ret = update_rmtp(&t.timer, rmtp); |
1538 | if (ret <= 0) |
1539 | goto out; |
1540 | } |
1541 | |
1542 | /* The other values in restart are already filled in */ |
1543 | ret = -ERESTART_RESTARTBLOCK; |
1544 | out: |
1545 | destroy_hrtimer_on_stack(&t.timer); |
1546 | return ret; |
1547 | } |
1548 | |
1549 | long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp, |
1550 | const enum hrtimer_mode mode, const clockid_t clockid) |
1551 | { |
1552 | struct restart_block *restart; |
1553 | struct hrtimer_sleeper t; |
1554 | int ret = 0; |
1555 | unsigned long slack; |
1556 | |
1557 | slack = current->timer_slack_ns; |
1558 | if (rt_task(current)) |
1559 | slack = 0; |
1560 | |
1561 | hrtimer_init_on_stack(&t.timer, clockid, mode); |
1562 | hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack); |
1563 | if (do_nanosleep(&t, mode)) |
1564 | goto out; |
1565 | |
1566 | /* Absolute timers do not update the rmtp value and restart: */ |
1567 | if (mode == HRTIMER_MODE_ABS) { |
1568 | ret = -ERESTARTNOHAND; |
1569 | goto out; |
1570 | } |
1571 | |
1572 | if (rmtp) { |
1573 | ret = update_rmtp(&t.timer, rmtp); |
1574 | if (ret <= 0) |
1575 | goto out; |
1576 | } |
1577 | |
1578 | restart = ¤t_thread_info()->restart_block; |
1579 | restart->fn = hrtimer_nanosleep_restart; |
1580 | restart->nanosleep.index = t.timer.base->index; |
1581 | restart->nanosleep.rmtp = rmtp; |
1582 | restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer); |
1583 | |
1584 | ret = -ERESTART_RESTARTBLOCK; |
1585 | out: |
1586 | destroy_hrtimer_on_stack(&t.timer); |
1587 | return ret; |
1588 | } |
1589 | |
1590 | SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp, |
1591 | struct timespec __user *, rmtp) |
1592 | { |
1593 | struct timespec tu; |
1594 | |
1595 | if (copy_from_user(&tu, rqtp, sizeof(tu))) |
1596 | return -EFAULT; |
1597 | |
1598 | if (!timespec_valid(&tu)) |
1599 | return -EINVAL; |
1600 | |
1601 | return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC); |
1602 | } |
1603 | |
1604 | /* |
1605 | * Functions related to boot-time initialization: |
1606 | */ |
1607 | static void __cpuinit init_hrtimers_cpu(int cpu) |
1608 | { |
1609 | struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu); |
1610 | int i; |
1611 | |
1612 | raw_spin_lock_init(&cpu_base->lock); |
1613 | |
1614 | for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) { |
1615 | cpu_base->clock_base[i].cpu_base = cpu_base; |
1616 | timerqueue_init_head(&cpu_base->clock_base[i].active); |
1617 | } |
1618 | |
1619 | hrtimer_init_hres(cpu_base); |
1620 | } |
1621 | |
1622 | #ifdef CONFIG_HOTPLUG_CPU |
1623 | |
1624 | static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base, |
1625 | struct hrtimer_clock_base *new_base) |
1626 | { |
1627 | struct hrtimer *timer; |
1628 | struct timerqueue_node *node; |
1629 | |
1630 | while ((node = timerqueue_getnext(&old_base->active))) { |
1631 | timer = container_of(node, struct hrtimer, node); |
1632 | BUG_ON(hrtimer_callback_running(timer)); |
1633 | debug_deactivate(timer); |
1634 | |
1635 | /* |
1636 | * Mark it as STATE_MIGRATE not INACTIVE otherwise the |
1637 | * timer could be seen as !active and just vanish away |
1638 | * under us on another CPU |
1639 | */ |
1640 | __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0); |
1641 | timer->base = new_base; |
1642 | /* |
1643 | * Enqueue the timers on the new cpu. This does not |
1644 | * reprogram the event device in case the timer |
1645 | * expires before the earliest on this CPU, but we run |
1646 | * hrtimer_interrupt after we migrated everything to |
1647 | * sort out already expired timers and reprogram the |
1648 | * event device. |
1649 | */ |
1650 | enqueue_hrtimer(timer, new_base); |
1651 | |
1652 | /* Clear the migration state bit */ |
1653 | timer->state &= ~HRTIMER_STATE_MIGRATE; |
1654 | } |
1655 | } |
1656 | |
1657 | static void migrate_hrtimers(int scpu) |
1658 | { |
1659 | struct hrtimer_cpu_base *old_base, *new_base; |
1660 | int i; |
1661 | |
1662 | BUG_ON(cpu_online(scpu)); |
1663 | tick_cancel_sched_timer(scpu); |
1664 | |
1665 | local_irq_disable(); |
1666 | old_base = &per_cpu(hrtimer_bases, scpu); |
1667 | new_base = &__get_cpu_var(hrtimer_bases); |
1668 | /* |
1669 | * The caller is globally serialized and nobody else |
1670 | * takes two locks at once, deadlock is not possible. |
1671 | */ |
1672 | raw_spin_lock(&new_base->lock); |
1673 | raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING); |
1674 | |
1675 | for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) { |
1676 | migrate_hrtimer_list(&old_base->clock_base[i], |
1677 | &new_base->clock_base[i]); |
1678 | } |
1679 | |
1680 | raw_spin_unlock(&old_base->lock); |
1681 | raw_spin_unlock(&new_base->lock); |
1682 | |
1683 | /* Check, if we got expired work to do */ |
1684 | __hrtimer_peek_ahead_timers(); |
1685 | local_irq_enable(); |
1686 | } |
1687 | |
1688 | #endif /* CONFIG_HOTPLUG_CPU */ |
1689 | |
1690 | static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self, |
1691 | unsigned long action, void *hcpu) |
1692 | { |
1693 | int scpu = (long)hcpu; |
1694 | |
1695 | switch (action) { |
1696 | |
1697 | case CPU_UP_PREPARE: |
1698 | case CPU_UP_PREPARE_FROZEN: |
1699 | init_hrtimers_cpu(scpu); |
1700 | break; |
1701 | |
1702 | #ifdef CONFIG_HOTPLUG_CPU |
1703 | case CPU_DYING: |
1704 | case CPU_DYING_FROZEN: |
1705 | clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DYING, &scpu); |
1706 | break; |
1707 | case CPU_DEAD: |
1708 | case CPU_DEAD_FROZEN: |
1709 | { |
1710 | clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu); |
1711 | migrate_hrtimers(scpu); |
1712 | break; |
1713 | } |
1714 | #endif |
1715 | |
1716 | default: |
1717 | break; |
1718 | } |
1719 | |
1720 | return NOTIFY_OK; |
1721 | } |
1722 | |
1723 | static struct notifier_block __cpuinitdata hrtimers_nb = { |
1724 | .notifier_call = hrtimer_cpu_notify, |
1725 | }; |
1726 | |
1727 | void __init hrtimers_init(void) |
1728 | { |
1729 | hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE, |
1730 | (void *)(long)smp_processor_id()); |
1731 | register_cpu_notifier(&hrtimers_nb); |
1732 | #ifdef CONFIG_HIGH_RES_TIMERS |
1733 | open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq); |
1734 | #endif |
1735 | } |
1736 | |
1737 | /** |
1738 | * schedule_hrtimeout_range_clock - sleep until timeout |
1739 | * @expires: timeout value (ktime_t) |
1740 | * @delta: slack in expires timeout (ktime_t) |
1741 | * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL |
1742 | * @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME |
1743 | */ |
1744 | int __sched |
1745 | schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta, |
1746 | const enum hrtimer_mode mode, int clock) |
1747 | { |
1748 | struct hrtimer_sleeper t; |
1749 | |
1750 | /* |
1751 | * Optimize when a zero timeout value is given. It does not |
1752 | * matter whether this is an absolute or a relative time. |
1753 | */ |
1754 | if (expires && !expires->tv64) { |
1755 | __set_current_state(TASK_RUNNING); |
1756 | return 0; |
1757 | } |
1758 | |
1759 | /* |
1760 | * A NULL parameter means "infinite" |
1761 | */ |
1762 | if (!expires) { |
1763 | schedule(); |
1764 | __set_current_state(TASK_RUNNING); |
1765 | return -EINTR; |
1766 | } |
1767 | |
1768 | hrtimer_init_on_stack(&t.timer, clock, mode); |
1769 | hrtimer_set_expires_range_ns(&t.timer, *expires, delta); |
1770 | |
1771 | hrtimer_init_sleeper(&t, current); |
1772 | |
1773 | hrtimer_start_expires(&t.timer, mode); |
1774 | if (!hrtimer_active(&t.timer)) |
1775 | t.task = NULL; |
1776 | |
1777 | if (likely(t.task)) |
1778 | schedule(); |
1779 | |
1780 | hrtimer_cancel(&t.timer); |
1781 | destroy_hrtimer_on_stack(&t.timer); |
1782 | |
1783 | __set_current_state(TASK_RUNNING); |
1784 | |
1785 | return !t.task ? 0 : -EINTR; |
1786 | } |
1787 | |
1788 | /** |
1789 | * schedule_hrtimeout_range - sleep until timeout |
1790 | * @expires: timeout value (ktime_t) |
1791 | * @delta: slack in expires timeout (ktime_t) |
1792 | * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL |
1793 | * |
1794 | * Make the current task sleep until the given expiry time has |
1795 | * elapsed. The routine will return immediately unless |
1796 | * the current task state has been set (see set_current_state()). |
1797 | * |
1798 | * The @delta argument gives the kernel the freedom to schedule the |
1799 | * actual wakeup to a time that is both power and performance friendly. |
1800 | * The kernel give the normal best effort behavior for "@expires+@delta", |
1801 | * but may decide to fire the timer earlier, but no earlier than @expires. |
1802 | * |
1803 | * You can set the task state as follows - |
1804 | * |
1805 | * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to |
1806 | * pass before the routine returns. |
1807 | * |
1808 | * %TASK_INTERRUPTIBLE - the routine may return early if a signal is |
1809 | * delivered to the current task. |
1810 | * |
1811 | * The current task state is guaranteed to be TASK_RUNNING when this |
1812 | * routine returns. |
1813 | * |
1814 | * Returns 0 when the timer has expired otherwise -EINTR |
1815 | */ |
1816 | int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta, |
1817 | const enum hrtimer_mode mode) |
1818 | { |
1819 | return schedule_hrtimeout_range_clock(expires, delta, mode, |
1820 | CLOCK_MONOTONIC); |
1821 | } |
1822 | EXPORT_SYMBOL_GPL(schedule_hrtimeout_range); |
1823 | |
1824 | /** |
1825 | * schedule_hrtimeout - sleep until timeout |
1826 | * @expires: timeout value (ktime_t) |
1827 | * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL |
1828 | * |
1829 | * Make the current task sleep until the given expiry time has |
1830 | * elapsed. The routine will return immediately unless |
1831 | * the current task state has been set (see set_current_state()). |
1832 | * |
1833 | * You can set the task state as follows - |
1834 | * |
1835 | * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to |
1836 | * pass before the routine returns. |
1837 | * |
1838 | * %TASK_INTERRUPTIBLE - the routine may return early if a signal is |
1839 | * delivered to the current task. |
1840 | * |
1841 | * The current task state is guaranteed to be TASK_RUNNING when this |
1842 | * routine returns. |
1843 | * |
1844 | * Returns 0 when the timer has expired otherwise -EINTR |
1845 | */ |
1846 | int __sched schedule_hrtimeout(ktime_t *expires, |
1847 | const enum hrtimer_mode mode) |
1848 | { |
1849 | return schedule_hrtimeout_range(expires, 0, mode); |
1850 | } |
1851 | EXPORT_SYMBOL_GPL(schedule_hrtimeout); |
1852 |
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