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1 | /* | |
2 | * linux/kernel/timer.c | |
3 | * | |
4 | * Kernel internal timers, basic process system calls | |
5 | * | |
6 | * Copyright (C) 1991, 1992 Linus Torvalds | |
7 | * | |
8 | * 1997-01-28 Modified by Finn Arne Gangstad to make timers scale better. | |
9 | * | |
10 | * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 | |
11 | * "A Kernel Model for Precision Timekeeping" by Dave Mills | |
12 | * 1998-12-24 Fixed a xtime SMP race (we need the xtime_lock rw spinlock to | |
13 | * serialize accesses to xtime/lost_ticks). | |
14 | * Copyright (C) 1998 Andrea Arcangeli | |
15 | * 1999-03-10 Improved NTP compatibility by Ulrich Windl | |
16 | * 2002-05-31 Move sys_sysinfo here and make its locking sane, Robert Love | |
17 | * 2000-10-05 Implemented scalable SMP per-CPU timer handling. | |
18 | * Copyright (C) 2000, 2001, 2002 Ingo Molnar | |
19 | * Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar | |
20 | */ | |
21 | ||
22 | #include <linux/kernel_stat.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/interrupt.h> | |
25 | #include <linux/percpu.h> | |
26 | #include <linux/init.h> | |
27 | #include <linux/mm.h> | |
28 | #include <linux/swap.h> | |
29 | #include <linux/pid_namespace.h> | |
30 | #include <linux/notifier.h> | |
31 | #include <linux/thread_info.h> | |
32 | #include <linux/time.h> | |
33 | #include <linux/jiffies.h> | |
34 | #include <linux/posix-timers.h> | |
35 | #include <linux/cpu.h> | |
36 | #include <linux/syscalls.h> | |
37 | #include <linux/delay.h> | |
38 | #include <linux/tick.h> | |
39 | #include <linux/kallsyms.h> | |
40 | #include <linux/irq_work.h> | |
41 | #include <linux/sched.h> | |
42 | #include <linux/slab.h> | |
43 | ||
44 | #include <asm/uaccess.h> | |
45 | #include <asm/unistd.h> | |
46 | #include <asm/div64.h> | |
47 | #include <asm/timex.h> | |
48 | #include <asm/io.h> | |
49 | ||
50 | #define CREATE_TRACE_POINTS | |
51 | #include <trace/events/timer.h> | |
52 | ||
53 | u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES; | |
54 | ||
55 | EXPORT_SYMBOL(jiffies_64); | |
56 | ||
57 | /* | |
58 | * per-CPU timer vector definitions: | |
59 | */ | |
60 | #define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6) | |
61 | #define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8) | |
62 | #define TVN_SIZE (1 << TVN_BITS) | |
63 | #define TVR_SIZE (1 << TVR_BITS) | |
64 | #define TVN_MASK (TVN_SIZE - 1) | |
65 | #define TVR_MASK (TVR_SIZE - 1) | |
66 | ||
67 | struct tvec { | |
68 | struct list_head vec[TVN_SIZE]; | |
69 | }; | |
70 | ||
71 | struct tvec_root { | |
72 | struct list_head vec[TVR_SIZE]; | |
73 | }; | |
74 | ||
75 | struct tvec_base { | |
76 | spinlock_t lock; | |
77 | struct timer_list *running_timer; | |
78 | unsigned long timer_jiffies; | |
79 | unsigned long next_timer; | |
80 | struct tvec_root tv1; | |
81 | struct tvec tv2; | |
82 | struct tvec tv3; | |
83 | struct tvec tv4; | |
84 | struct tvec tv5; | |
85 | } ____cacheline_aligned; | |
86 | ||
87 | struct tvec_base boot_tvec_bases; | |
88 | EXPORT_SYMBOL(boot_tvec_bases); | |
89 | static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases; | |
90 | ||
91 | /* | |
92 | * Note that all tvec_bases are 2 byte aligned and lower bit of | |
93 | * base in timer_list is guaranteed to be zero. Use the LSB to | |
94 | * indicate whether the timer is deferrable. | |
95 | * | |
96 | * A deferrable timer will work normally when the system is busy, but | |
97 | * will not cause a CPU to come out of idle just to service it; instead, | |
98 | * the timer will be serviced when the CPU eventually wakes up with a | |
99 | * subsequent non-deferrable timer. | |
100 | */ | |
101 | #define TBASE_DEFERRABLE_FLAG (0x1) | |
102 | ||
103 | /* Functions below help us manage 'deferrable' flag */ | |
104 | static inline unsigned int tbase_get_deferrable(struct tvec_base *base) | |
105 | { | |
106 | return ((unsigned int)(unsigned long)base & TBASE_DEFERRABLE_FLAG); | |
107 | } | |
108 | ||
109 | static inline struct tvec_base *tbase_get_base(struct tvec_base *base) | |
110 | { | |
111 | return ((struct tvec_base *)((unsigned long)base & ~TBASE_DEFERRABLE_FLAG)); | |
112 | } | |
113 | ||
114 | static inline void timer_set_deferrable(struct timer_list *timer) | |
115 | { | |
116 | timer->base = ((struct tvec_base *)((unsigned long)(timer->base) | | |
117 | TBASE_DEFERRABLE_FLAG)); | |
118 | } | |
119 | ||
120 | static inline void | |
121 | timer_set_base(struct timer_list *timer, struct tvec_base *new_base) | |
122 | { | |
123 | timer->base = (struct tvec_base *)((unsigned long)(new_base) | | |
124 | tbase_get_deferrable(timer->base)); | |
125 | } | |
126 | ||
127 | static unsigned long round_jiffies_common(unsigned long j, int cpu, | |
128 | bool force_up) | |
129 | { | |
130 | int rem; | |
131 | unsigned long original = j; | |
132 | ||
133 | /* | |
134 | * We don't want all cpus firing their timers at once hitting the | |
135 | * same lock or cachelines, so we skew each extra cpu with an extra | |
136 | * 3 jiffies. This 3 jiffies came originally from the mm/ code which | |
137 | * already did this. | |
138 | * The skew is done by adding 3*cpunr, then round, then subtract this | |
139 | * extra offset again. | |
140 | */ | |
141 | j += cpu * 3; | |
142 | ||
143 | rem = j % HZ; | |
144 | ||
145 | /* | |
146 | * If the target jiffie is just after a whole second (which can happen | |
147 | * due to delays of the timer irq, long irq off times etc etc) then | |
148 | * we should round down to the whole second, not up. Use 1/4th second | |
149 | * as cutoff for this rounding as an extreme upper bound for this. | |
150 | * But never round down if @force_up is set. | |
151 | */ | |
152 | if (rem < HZ/4 && !force_up) /* round down */ | |
153 | j = j - rem; | |
154 | else /* round up */ | |
155 | j = j - rem + HZ; | |
156 | ||
157 | /* now that we have rounded, subtract the extra skew again */ | |
158 | j -= cpu * 3; | |
159 | ||
160 | if (j <= jiffies) /* rounding ate our timeout entirely; */ | |
161 | return original; | |
162 | return j; | |
163 | } | |
164 | ||
165 | /** | |
166 | * __round_jiffies - function to round jiffies to a full second | |
167 | * @j: the time in (absolute) jiffies that should be rounded | |
168 | * @cpu: the processor number on which the timeout will happen | |
169 | * | |
170 | * __round_jiffies() rounds an absolute time in the future (in jiffies) | |
171 | * up or down to (approximately) full seconds. This is useful for timers | |
172 | * for which the exact time they fire does not matter too much, as long as | |
173 | * they fire approximately every X seconds. | |
174 | * | |
175 | * By rounding these timers to whole seconds, all such timers will fire | |
176 | * at the same time, rather than at various times spread out. The goal | |
177 | * of this is to have the CPU wake up less, which saves power. | |
178 | * | |
179 | * The exact rounding is skewed for each processor to avoid all | |
180 | * processors firing at the exact same time, which could lead | |
181 | * to lock contention or spurious cache line bouncing. | |
182 | * | |
183 | * The return value is the rounded version of the @j parameter. | |
184 | */ | |
185 | unsigned long __round_jiffies(unsigned long j, int cpu) | |
186 | { | |
187 | return round_jiffies_common(j, cpu, false); | |
188 | } | |
189 | EXPORT_SYMBOL_GPL(__round_jiffies); | |
190 | ||
191 | /** | |
192 | * __round_jiffies_relative - function to round jiffies to a full second | |
193 | * @j: the time in (relative) jiffies that should be rounded | |
194 | * @cpu: the processor number on which the timeout will happen | |
195 | * | |
196 | * __round_jiffies_relative() rounds a time delta in the future (in jiffies) | |
197 | * up or down to (approximately) full seconds. This is useful for timers | |
198 | * for which the exact time they fire does not matter too much, as long as | |
199 | * they fire approximately every X seconds. | |
200 | * | |
201 | * By rounding these timers to whole seconds, all such timers will fire | |
202 | * at the same time, rather than at various times spread out. The goal | |
203 | * of this is to have the CPU wake up less, which saves power. | |
204 | * | |
205 | * The exact rounding is skewed for each processor to avoid all | |
206 | * processors firing at the exact same time, which could lead | |
207 | * to lock contention or spurious cache line bouncing. | |
208 | * | |
209 | * The return value is the rounded version of the @j parameter. | |
210 | */ | |
211 | unsigned long __round_jiffies_relative(unsigned long j, int cpu) | |
212 | { | |
213 | unsigned long j0 = jiffies; | |
214 | ||
215 | /* Use j0 because jiffies might change while we run */ | |
216 | return round_jiffies_common(j + j0, cpu, false) - j0; | |
217 | } | |
218 | EXPORT_SYMBOL_GPL(__round_jiffies_relative); | |
219 | ||
220 | /** | |
221 | * round_jiffies - function to round jiffies to a full second | |
222 | * @j: the time in (absolute) jiffies that should be rounded | |
223 | * | |
224 | * round_jiffies() rounds an absolute time in the future (in jiffies) | |
225 | * up or down to (approximately) full seconds. This is useful for timers | |
226 | * for which the exact time they fire does not matter too much, as long as | |
227 | * they fire approximately every X seconds. | |
228 | * | |
229 | * By rounding these timers to whole seconds, all such timers will fire | |
230 | * at the same time, rather than at various times spread out. The goal | |
231 | * of this is to have the CPU wake up less, which saves power. | |
232 | * | |
233 | * The return value is the rounded version of the @j parameter. | |
234 | */ | |
235 | unsigned long round_jiffies(unsigned long j) | |
236 | { | |
237 | return round_jiffies_common(j, raw_smp_processor_id(), false); | |
238 | } | |
239 | EXPORT_SYMBOL_GPL(round_jiffies); | |
240 | ||
241 | /** | |
242 | * round_jiffies_relative - function to round jiffies to a full second | |
243 | * @j: the time in (relative) jiffies that should be rounded | |
244 | * | |
245 | * round_jiffies_relative() rounds a time delta in the future (in jiffies) | |
246 | * up or down to (approximately) full seconds. This is useful for timers | |
247 | * for which the exact time they fire does not matter too much, as long as | |
248 | * they fire approximately every X seconds. | |
249 | * | |
250 | * By rounding these timers to whole seconds, all such timers will fire | |
251 | * at the same time, rather than at various times spread out. The goal | |
252 | * of this is to have the CPU wake up less, which saves power. | |
253 | * | |
254 | * The return value is the rounded version of the @j parameter. | |
255 | */ | |
256 | unsigned long round_jiffies_relative(unsigned long j) | |
257 | { | |
258 | return __round_jiffies_relative(j, raw_smp_processor_id()); | |
259 | } | |
260 | EXPORT_SYMBOL_GPL(round_jiffies_relative); | |
261 | ||
262 | /** | |
263 | * __round_jiffies_up - function to round jiffies up to a full second | |
264 | * @j: the time in (absolute) jiffies that should be rounded | |
265 | * @cpu: the processor number on which the timeout will happen | |
266 | * | |
267 | * This is the same as __round_jiffies() except that it will never | |
268 | * round down. This is useful for timeouts for which the exact time | |
269 | * of firing does not matter too much, as long as they don't fire too | |
270 | * early. | |
271 | */ | |
272 | unsigned long __round_jiffies_up(unsigned long j, int cpu) | |
273 | { | |
274 | return round_jiffies_common(j, cpu, true); | |
275 | } | |
276 | EXPORT_SYMBOL_GPL(__round_jiffies_up); | |
277 | ||
278 | /** | |
279 | * __round_jiffies_up_relative - function to round jiffies up to a full second | |
280 | * @j: the time in (relative) jiffies that should be rounded | |
281 | * @cpu: the processor number on which the timeout will happen | |
282 | * | |
283 | * This is the same as __round_jiffies_relative() except that it will never | |
284 | * round down. This is useful for timeouts for which the exact time | |
285 | * of firing does not matter too much, as long as they don't fire too | |
286 | * early. | |
287 | */ | |
288 | unsigned long __round_jiffies_up_relative(unsigned long j, int cpu) | |
289 | { | |
290 | unsigned long j0 = jiffies; | |
291 | ||
292 | /* Use j0 because jiffies might change while we run */ | |
293 | return round_jiffies_common(j + j0, cpu, true) - j0; | |
294 | } | |
295 | EXPORT_SYMBOL_GPL(__round_jiffies_up_relative); | |
296 | ||
297 | /** | |
298 | * round_jiffies_up - function to round jiffies up to a full second | |
299 | * @j: the time in (absolute) jiffies that should be rounded | |
300 | * | |
301 | * This is the same as round_jiffies() except that it will never | |
302 | * round down. This is useful for timeouts for which the exact time | |
303 | * of firing does not matter too much, as long as they don't fire too | |
304 | * early. | |
305 | */ | |
306 | unsigned long round_jiffies_up(unsigned long j) | |
307 | { | |
308 | return round_jiffies_common(j, raw_smp_processor_id(), true); | |
309 | } | |
310 | EXPORT_SYMBOL_GPL(round_jiffies_up); | |
311 | ||
312 | /** | |
313 | * round_jiffies_up_relative - function to round jiffies up to a full second | |
314 | * @j: the time in (relative) jiffies that should be rounded | |
315 | * | |
316 | * This is the same as round_jiffies_relative() except that it will never | |
317 | * round down. This is useful for timeouts for which the exact time | |
318 | * of firing does not matter too much, as long as they don't fire too | |
319 | * early. | |
320 | */ | |
321 | unsigned long round_jiffies_up_relative(unsigned long j) | |
322 | { | |
323 | return __round_jiffies_up_relative(j, raw_smp_processor_id()); | |
324 | } | |
325 | EXPORT_SYMBOL_GPL(round_jiffies_up_relative); | |
326 | ||
327 | /** | |
328 | * set_timer_slack - set the allowed slack for a timer | |
329 | * @timer: the timer to be modified | |
330 | * @slack_hz: the amount of time (in jiffies) allowed for rounding | |
331 | * | |
332 | * Set the amount of time, in jiffies, that a certain timer has | |
333 | * in terms of slack. By setting this value, the timer subsystem | |
334 | * will schedule the actual timer somewhere between | |
335 | * the time mod_timer() asks for, and that time plus the slack. | |
336 | * | |
337 | * By setting the slack to -1, a percentage of the delay is used | |
338 | * instead. | |
339 | */ | |
340 | void set_timer_slack(struct timer_list *timer, int slack_hz) | |
341 | { | |
342 | timer->slack = slack_hz; | |
343 | } | |
344 | EXPORT_SYMBOL_GPL(set_timer_slack); | |
345 | ||
346 | ||
347 | static inline void set_running_timer(struct tvec_base *base, | |
348 | struct timer_list *timer) | |
349 | { | |
350 | #ifdef CONFIG_SMP | |
351 | base->running_timer = timer; | |
352 | #endif | |
353 | } | |
354 | ||
355 | static void internal_add_timer(struct tvec_base *base, struct timer_list *timer) | |
356 | { | |
357 | unsigned long expires = timer->expires; | |
358 | unsigned long idx = expires - base->timer_jiffies; | |
359 | struct list_head *vec; | |
360 | ||
361 | if (idx < TVR_SIZE) { | |
362 | int i = expires & TVR_MASK; | |
363 | vec = base->tv1.vec + i; | |
364 | } else if (idx < 1 << (TVR_BITS + TVN_BITS)) { | |
365 | int i = (expires >> TVR_BITS) & TVN_MASK; | |
366 | vec = base->tv2.vec + i; | |
367 | } else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) { | |
368 | int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK; | |
369 | vec = base->tv3.vec + i; | |
370 | } else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) { | |
371 | int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK; | |
372 | vec = base->tv4.vec + i; | |
373 | } else if ((signed long) idx < 0) { | |
374 | /* | |
375 | * Can happen if you add a timer with expires == jiffies, | |
376 | * or you set a timer to go off in the past | |
377 | */ | |
378 | vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK); | |
379 | } else { | |
380 | int i; | |
381 | /* If the timeout is larger than 0xffffffff on 64-bit | |
382 | * architectures then we use the maximum timeout: | |
383 | */ | |
384 | if (idx > 0xffffffffUL) { | |
385 | idx = 0xffffffffUL; | |
386 | expires = idx + base->timer_jiffies; | |
387 | } | |
388 | i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK; | |
389 | vec = base->tv5.vec + i; | |
390 | } | |
391 | /* | |
392 | * Timers are FIFO: | |
393 | */ | |
394 | list_add_tail(&timer->entry, vec); | |
395 | } | |
396 | ||
397 | #ifdef CONFIG_TIMER_STATS | |
398 | void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr) | |
399 | { | |
400 | if (timer->start_site) | |
401 | return; | |
402 | ||
403 | timer->start_site = addr; | |
404 | memcpy(timer->start_comm, current->comm, TASK_COMM_LEN); | |
405 | timer->start_pid = current->pid; | |
406 | } | |
407 | ||
408 | static void timer_stats_account_timer(struct timer_list *timer) | |
409 | { | |
410 | unsigned int flag = 0; | |
411 | ||
412 | if (likely(!timer->start_site)) | |
413 | return; | |
414 | if (unlikely(tbase_get_deferrable(timer->base))) | |
415 | flag |= TIMER_STATS_FLAG_DEFERRABLE; | |
416 | ||
417 | timer_stats_update_stats(timer, timer->start_pid, timer->start_site, | |
418 | timer->function, timer->start_comm, flag); | |
419 | } | |
420 | ||
421 | #else | |
422 | static void timer_stats_account_timer(struct timer_list *timer) {} | |
423 | #endif | |
424 | ||
425 | #ifdef CONFIG_DEBUG_OBJECTS_TIMERS | |
426 | ||
427 | static struct debug_obj_descr timer_debug_descr; | |
428 | ||
429 | /* | |
430 | * fixup_init is called when: | |
431 | * - an active object is initialized | |
432 | */ | |
433 | static int timer_fixup_init(void *addr, enum debug_obj_state state) | |
434 | { | |
435 | struct timer_list *timer = addr; | |
436 | ||
437 | switch (state) { | |
438 | case ODEBUG_STATE_ACTIVE: | |
439 | del_timer_sync(timer); | |
440 | debug_object_init(timer, &timer_debug_descr); | |
441 | return 1; | |
442 | default: | |
443 | return 0; | |
444 | } | |
445 | } | |
446 | ||
447 | /* | |
448 | * fixup_activate is called when: | |
449 | * - an active object is activated | |
450 | * - an unknown object is activated (might be a statically initialized object) | |
451 | */ | |
452 | static int timer_fixup_activate(void *addr, enum debug_obj_state state) | |
453 | { | |
454 | struct timer_list *timer = addr; | |
455 | ||
456 | switch (state) { | |
457 | ||
458 | case ODEBUG_STATE_NOTAVAILABLE: | |
459 | /* | |
460 | * This is not really a fixup. The timer was | |
461 | * statically initialized. We just make sure that it | |
462 | * is tracked in the object tracker. | |
463 | */ | |
464 | if (timer->entry.next == NULL && | |
465 | timer->entry.prev == TIMER_ENTRY_STATIC) { | |
466 | debug_object_init(timer, &timer_debug_descr); | |
467 | debug_object_activate(timer, &timer_debug_descr); | |
468 | return 0; | |
469 | } else { | |
470 | WARN_ON_ONCE(1); | |
471 | } | |
472 | return 0; | |
473 | ||
474 | case ODEBUG_STATE_ACTIVE: | |
475 | WARN_ON(1); | |
476 | ||
477 | default: | |
478 | return 0; | |
479 | } | |
480 | } | |
481 | ||
482 | /* | |
483 | * fixup_free is called when: | |
484 | * - an active object is freed | |
485 | */ | |
486 | static int timer_fixup_free(void *addr, enum debug_obj_state state) | |
487 | { | |
488 | struct timer_list *timer = addr; | |
489 | ||
490 | switch (state) { | |
491 | case ODEBUG_STATE_ACTIVE: | |
492 | del_timer_sync(timer); | |
493 | debug_object_free(timer, &timer_debug_descr); | |
494 | return 1; | |
495 | default: | |
496 | return 0; | |
497 | } | |
498 | } | |
499 | ||
500 | static struct debug_obj_descr timer_debug_descr = { | |
501 | .name = "timer_list", | |
502 | .fixup_init = timer_fixup_init, | |
503 | .fixup_activate = timer_fixup_activate, | |
504 | .fixup_free = timer_fixup_free, | |
505 | }; | |
506 | ||
507 | static inline void debug_timer_init(struct timer_list *timer) | |
508 | { | |
509 | debug_object_init(timer, &timer_debug_descr); | |
510 | } | |
511 | ||
512 | static inline void debug_timer_activate(struct timer_list *timer) | |
513 | { | |
514 | debug_object_activate(timer, &timer_debug_descr); | |
515 | } | |
516 | ||
517 | static inline void debug_timer_deactivate(struct timer_list *timer) | |
518 | { | |
519 | debug_object_deactivate(timer, &timer_debug_descr); | |
520 | } | |
521 | ||
522 | static inline void debug_timer_free(struct timer_list *timer) | |
523 | { | |
524 | debug_object_free(timer, &timer_debug_descr); | |
525 | } | |
526 | ||
527 | static void __init_timer(struct timer_list *timer, | |
528 | const char *name, | |
529 | struct lock_class_key *key); | |
530 | ||
531 | void init_timer_on_stack_key(struct timer_list *timer, | |
532 | const char *name, | |
533 | struct lock_class_key *key) | |
534 | { | |
535 | debug_object_init_on_stack(timer, &timer_debug_descr); | |
536 | __init_timer(timer, name, key); | |
537 | } | |
538 | EXPORT_SYMBOL_GPL(init_timer_on_stack_key); | |
539 | ||
540 | void destroy_timer_on_stack(struct timer_list *timer) | |
541 | { | |
542 | debug_object_free(timer, &timer_debug_descr); | |
543 | } | |
544 | EXPORT_SYMBOL_GPL(destroy_timer_on_stack); | |
545 | ||
546 | #else | |
547 | static inline void debug_timer_init(struct timer_list *timer) { } | |
548 | static inline void debug_timer_activate(struct timer_list *timer) { } | |
549 | static inline void debug_timer_deactivate(struct timer_list *timer) { } | |
550 | #endif | |
551 | ||
552 | static inline void debug_init(struct timer_list *timer) | |
553 | { | |
554 | debug_timer_init(timer); | |
555 | trace_timer_init(timer); | |
556 | } | |
557 | ||
558 | static inline void | |
559 | debug_activate(struct timer_list *timer, unsigned long expires) | |
560 | { | |
561 | debug_timer_activate(timer); | |
562 | trace_timer_start(timer, expires); | |
563 | } | |
564 | ||
565 | static inline void debug_deactivate(struct timer_list *timer) | |
566 | { | |
567 | debug_timer_deactivate(timer); | |
568 | trace_timer_cancel(timer); | |
569 | } | |
570 | ||
571 | static void __init_timer(struct timer_list *timer, | |
572 | const char *name, | |
573 | struct lock_class_key *key) | |
574 | { | |
575 | timer->entry.next = NULL; | |
576 | timer->base = __raw_get_cpu_var(tvec_bases); | |
577 | timer->slack = -1; | |
578 | #ifdef CONFIG_TIMER_STATS | |
579 | timer->start_site = NULL; | |
580 | timer->start_pid = -1; | |
581 | memset(timer->start_comm, 0, TASK_COMM_LEN); | |
582 | #endif | |
583 | lockdep_init_map(&timer->lockdep_map, name, key, 0); | |
584 | } | |
585 | ||
586 | void setup_deferrable_timer_on_stack_key(struct timer_list *timer, | |
587 | const char *name, | |
588 | struct lock_class_key *key, | |
589 | void (*function)(unsigned long), | |
590 | unsigned long data) | |
591 | { | |
592 | timer->function = function; | |
593 | timer->data = data; | |
594 | init_timer_on_stack_key(timer, name, key); | |
595 | timer_set_deferrable(timer); | |
596 | } | |
597 | EXPORT_SYMBOL_GPL(setup_deferrable_timer_on_stack_key); | |
598 | ||
599 | /** | |
600 | * init_timer_key - initialize a timer | |
601 | * @timer: the timer to be initialized | |
602 | * @name: name of the timer | |
603 | * @key: lockdep class key of the fake lock used for tracking timer | |
604 | * sync lock dependencies | |
605 | * | |
606 | * init_timer_key() must be done to a timer prior calling *any* of the | |
607 | * other timer functions. | |
608 | */ | |
609 | void init_timer_key(struct timer_list *timer, | |
610 | const char *name, | |
611 | struct lock_class_key *key) | |
612 | { | |
613 | debug_init(timer); | |
614 | __init_timer(timer, name, key); | |
615 | } | |
616 | EXPORT_SYMBOL(init_timer_key); | |
617 | ||
618 | void init_timer_deferrable_key(struct timer_list *timer, | |
619 | const char *name, | |
620 | struct lock_class_key *key) | |
621 | { | |
622 | init_timer_key(timer, name, key); | |
623 | timer_set_deferrable(timer); | |
624 | } | |
625 | EXPORT_SYMBOL(init_timer_deferrable_key); | |
626 | ||
627 | static inline void detach_timer(struct timer_list *timer, | |
628 | int clear_pending) | |
629 | { | |
630 | struct list_head *entry = &timer->entry; | |
631 | ||
632 | debug_deactivate(timer); | |
633 | ||
634 | __list_del(entry->prev, entry->next); | |
635 | if (clear_pending) | |
636 | entry->next = NULL; | |
637 | entry->prev = LIST_POISON2; | |
638 | } | |
639 | ||
640 | /* | |
641 | * We are using hashed locking: holding per_cpu(tvec_bases).lock | |
642 | * means that all timers which are tied to this base via timer->base are | |
643 | * locked, and the base itself is locked too. | |
644 | * | |
645 | * So __run_timers/migrate_timers can safely modify all timers which could | |
646 | * be found on ->tvX lists. | |
647 | * | |
648 | * When the timer's base is locked, and the timer removed from list, it is | |
649 | * possible to set timer->base = NULL and drop the lock: the timer remains | |
650 | * locked. | |
651 | */ | |
652 | static struct tvec_base *lock_timer_base(struct timer_list *timer, | |
653 | unsigned long *flags) | |
654 | __acquires(timer->base->lock) | |
655 | { | |
656 | struct tvec_base *base; | |
657 | ||
658 | for (;;) { | |
659 | struct tvec_base *prelock_base = timer->base; | |
660 | base = tbase_get_base(prelock_base); | |
661 | if (likely(base != NULL)) { | |
662 | spin_lock_irqsave(&base->lock, *flags); | |
663 | if (likely(prelock_base == timer->base)) | |
664 | return base; | |
665 | /* The timer has migrated to another CPU */ | |
666 | spin_unlock_irqrestore(&base->lock, *flags); | |
667 | } | |
668 | cpu_relax(); | |
669 | } | |
670 | } | |
671 | ||
672 | static inline int | |
673 | __mod_timer(struct timer_list *timer, unsigned long expires, | |
674 | bool pending_only, int pinned) | |
675 | { | |
676 | struct tvec_base *base, *new_base; | |
677 | unsigned long flags; | |
678 | int ret = 0 , cpu; | |
679 | ||
680 | timer_stats_timer_set_start_info(timer); | |
681 | BUG_ON(!timer->function); | |
682 | ||
683 | base = lock_timer_base(timer, &flags); | |
684 | ||
685 | if (timer_pending(timer)) { | |
686 | detach_timer(timer, 0); | |
687 | if (timer->expires == base->next_timer && | |
688 | !tbase_get_deferrable(timer->base)) | |
689 | base->next_timer = base->timer_jiffies; | |
690 | ret = 1; | |
691 | } else { | |
692 | if (pending_only) | |
693 | goto out_unlock; | |
694 | } | |
695 | ||
696 | debug_activate(timer, expires); | |
697 | ||
698 | cpu = smp_processor_id(); | |
699 | ||
700 | #if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP) | |
701 | if (!pinned && get_sysctl_timer_migration() && idle_cpu(cpu)) | |
702 | cpu = get_nohz_timer_target(); | |
703 | #endif | |
704 | new_base = per_cpu(tvec_bases, cpu); | |
705 | ||
706 | if (base != new_base) { | |
707 | /* | |
708 | * We are trying to schedule the timer on the local CPU. | |
709 | * However we can't change timer's base while it is running, | |
710 | * otherwise del_timer_sync() can't detect that the timer's | |
711 | * handler yet has not finished. This also guarantees that | |
712 | * the timer is serialized wrt itself. | |
713 | */ | |
714 | if (likely(base->running_timer != timer)) { | |
715 | /* See the comment in lock_timer_base() */ | |
716 | timer_set_base(timer, NULL); | |
717 | spin_unlock(&base->lock); | |
718 | base = new_base; | |
719 | spin_lock(&base->lock); | |
720 | timer_set_base(timer, base); | |
721 | } | |
722 | } | |
723 | ||
724 | timer->expires = expires; | |
725 | if (time_before(timer->expires, base->next_timer) && | |
726 | !tbase_get_deferrable(timer->base)) | |
727 | base->next_timer = timer->expires; | |
728 | internal_add_timer(base, timer); | |
729 | ||
730 | out_unlock: | |
731 | spin_unlock_irqrestore(&base->lock, flags); | |
732 | ||
733 | return ret; | |
734 | } | |
735 | ||
736 | /** | |
737 | * mod_timer_pending - modify a pending timer's timeout | |
738 | * @timer: the pending timer to be modified | |
739 | * @expires: new timeout in jiffies | |
740 | * | |
741 | * mod_timer_pending() is the same for pending timers as mod_timer(), | |
742 | * but will not re-activate and modify already deleted timers. | |
743 | * | |
744 | * It is useful for unserialized use of timers. | |
745 | */ | |
746 | int mod_timer_pending(struct timer_list *timer, unsigned long expires) | |
747 | { | |
748 | return __mod_timer(timer, expires, true, TIMER_NOT_PINNED); | |
749 | } | |
750 | EXPORT_SYMBOL(mod_timer_pending); | |
751 | ||
752 | /* | |
753 | * Decide where to put the timer while taking the slack into account | |
754 | * | |
755 | * Algorithm: | |
756 | * 1) calculate the maximum (absolute) time | |
757 | * 2) calculate the highest bit where the expires and new max are different | |
758 | * 3) use this bit to make a mask | |
759 | * 4) use the bitmask to round down the maximum time, so that all last | |
760 | * bits are zeros | |
761 | */ | |
762 | static inline | |
763 | unsigned long apply_slack(struct timer_list *timer, unsigned long expires) | |
764 | { | |
765 | unsigned long expires_limit, mask; | |
766 | int bit; | |
767 | ||
768 | expires_limit = expires; | |
769 | ||
770 | if (timer->slack >= 0) { | |
771 | expires_limit = expires + timer->slack; | |
772 | } else { | |
773 | unsigned long now = jiffies; | |
774 | ||
775 | /* No slack, if already expired else auto slack 0.4% */ | |
776 | if (time_after(expires, now)) | |
777 | expires_limit = expires + (expires - now)/256; | |
778 | } | |
779 | mask = expires ^ expires_limit; | |
780 | if (mask == 0) | |
781 | return expires; | |
782 | ||
783 | bit = find_last_bit(&mask, BITS_PER_LONG); | |
784 | ||
785 | mask = (1 << bit) - 1; | |
786 | ||
787 | expires_limit = expires_limit & ~(mask); | |
788 | ||
789 | return expires_limit; | |
790 | } | |
791 | ||
792 | /** | |
793 | * mod_timer - modify a timer's timeout | |
794 | * @timer: the timer to be modified | |
795 | * @expires: new timeout in jiffies | |
796 | * | |
797 | * mod_timer() is a more efficient way to update the expire field of an | |
798 | * active timer (if the timer is inactive it will be activated) | |
799 | * | |
800 | * mod_timer(timer, expires) is equivalent to: | |
801 | * | |
802 | * del_timer(timer); timer->expires = expires; add_timer(timer); | |
803 | * | |
804 | * Note that if there are multiple unserialized concurrent users of the | |
805 | * same timer, then mod_timer() is the only safe way to modify the timeout, | |
806 | * since add_timer() cannot modify an already running timer. | |
807 | * | |
808 | * The function returns whether it has modified a pending timer or not. | |
809 | * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an | |
810 | * active timer returns 1.) | |
811 | */ | |
812 | int mod_timer(struct timer_list *timer, unsigned long expires) | |
813 | { | |
814 | /* | |
815 | * This is a common optimization triggered by the | |
816 | * networking code - if the timer is re-modified | |
817 | * to be the same thing then just return: | |
818 | */ | |
819 | if (timer_pending(timer) && timer->expires == expires) | |
820 | return 1; | |
821 | ||
822 | expires = apply_slack(timer, expires); | |
823 | ||
824 | return __mod_timer(timer, expires, false, TIMER_NOT_PINNED); | |
825 | } | |
826 | EXPORT_SYMBOL(mod_timer); | |
827 | ||
828 | /** | |
829 | * mod_timer_pinned - modify a timer's timeout | |
830 | * @timer: the timer to be modified | |
831 | * @expires: new timeout in jiffies | |
832 | * | |
833 | * mod_timer_pinned() is a way to update the expire field of an | |
834 | * active timer (if the timer is inactive it will be activated) | |
835 | * and not allow the timer to be migrated to a different CPU. | |
836 | * | |
837 | * mod_timer_pinned(timer, expires) is equivalent to: | |
838 | * | |
839 | * del_timer(timer); timer->expires = expires; add_timer(timer); | |
840 | */ | |
841 | int mod_timer_pinned(struct timer_list *timer, unsigned long expires) | |
842 | { | |
843 | if (timer->expires == expires && timer_pending(timer)) | |
844 | return 1; | |
845 | ||
846 | return __mod_timer(timer, expires, false, TIMER_PINNED); | |
847 | } | |
848 | EXPORT_SYMBOL(mod_timer_pinned); | |
849 | ||
850 | /** | |
851 | * add_timer - start a timer | |
852 | * @timer: the timer to be added | |
853 | * | |
854 | * The kernel will do a ->function(->data) callback from the | |
855 | * timer interrupt at the ->expires point in the future. The | |
856 | * current time is 'jiffies'. | |
857 | * | |
858 | * The timer's ->expires, ->function (and if the handler uses it, ->data) | |
859 | * fields must be set prior calling this function. | |
860 | * | |
861 | * Timers with an ->expires field in the past will be executed in the next | |
862 | * timer tick. | |
863 | */ | |
864 | void add_timer(struct timer_list *timer) | |
865 | { | |
866 | BUG_ON(timer_pending(timer)); | |
867 | mod_timer(timer, timer->expires); | |
868 | } | |
869 | EXPORT_SYMBOL(add_timer); | |
870 | ||
871 | /** | |
872 | * add_timer_on - start a timer on a particular CPU | |
873 | * @timer: the timer to be added | |
874 | * @cpu: the CPU to start it on | |
875 | * | |
876 | * This is not very scalable on SMP. Double adds are not possible. | |
877 | */ | |
878 | void add_timer_on(struct timer_list *timer, int cpu) | |
879 | { | |
880 | struct tvec_base *base = per_cpu(tvec_bases, cpu); | |
881 | unsigned long flags; | |
882 | ||
883 | timer_stats_timer_set_start_info(timer); | |
884 | BUG_ON(timer_pending(timer) || !timer->function); | |
885 | spin_lock_irqsave(&base->lock, flags); | |
886 | timer_set_base(timer, base); | |
887 | debug_activate(timer, timer->expires); | |
888 | if (time_before(timer->expires, base->next_timer) && | |
889 | !tbase_get_deferrable(timer->base)) | |
890 | base->next_timer = timer->expires; | |
891 | internal_add_timer(base, timer); | |
892 | /* | |
893 | * Check whether the other CPU is idle and needs to be | |
894 | * triggered to reevaluate the timer wheel when nohz is | |
895 | * active. We are protected against the other CPU fiddling | |
896 | * with the timer by holding the timer base lock. This also | |
897 | * makes sure that a CPU on the way to idle can not evaluate | |
898 | * the timer wheel. | |
899 | */ | |
900 | wake_up_idle_cpu(cpu); | |
901 | spin_unlock_irqrestore(&base->lock, flags); | |
902 | } | |
903 | EXPORT_SYMBOL_GPL(add_timer_on); | |
904 | ||
905 | /** | |
906 | * del_timer - deactive a timer. | |
907 | * @timer: the timer to be deactivated | |
908 | * | |
909 | * del_timer() deactivates a timer - this works on both active and inactive | |
910 | * timers. | |
911 | * | |
912 | * The function returns whether it has deactivated a pending timer or not. | |
913 | * (ie. del_timer() of an inactive timer returns 0, del_timer() of an | |
914 | * active timer returns 1.) | |
915 | */ | |
916 | int del_timer(struct timer_list *timer) | |
917 | { | |
918 | struct tvec_base *base; | |
919 | unsigned long flags; | |
920 | int ret = 0; | |
921 | ||
922 | timer_stats_timer_clear_start_info(timer); | |
923 | if (timer_pending(timer)) { | |
924 | base = lock_timer_base(timer, &flags); | |
925 | if (timer_pending(timer)) { | |
926 | detach_timer(timer, 1); | |
927 | if (timer->expires == base->next_timer && | |
928 | !tbase_get_deferrable(timer->base)) | |
929 | base->next_timer = base->timer_jiffies; | |
930 | ret = 1; | |
931 | } | |
932 | spin_unlock_irqrestore(&base->lock, flags); | |
933 | } | |
934 | ||
935 | return ret; | |
936 | } | |
937 | EXPORT_SYMBOL(del_timer); | |
938 | ||
939 | #ifdef CONFIG_SMP | |
940 | /** | |
941 | * try_to_del_timer_sync - Try to deactivate a timer | |
942 | * @timer: timer do del | |
943 | * | |
944 | * This function tries to deactivate a timer. Upon successful (ret >= 0) | |
945 | * exit the timer is not queued and the handler is not running on any CPU. | |
946 | * | |
947 | * It must not be called from interrupt contexts. | |
948 | */ | |
949 | int try_to_del_timer_sync(struct timer_list *timer) | |
950 | { | |
951 | struct tvec_base *base; | |
952 | unsigned long flags; | |
953 | int ret = -1; | |
954 | ||
955 | base = lock_timer_base(timer, &flags); | |
956 | ||
957 | if (base->running_timer == timer) | |
958 | goto out; | |
959 | ||
960 | timer_stats_timer_clear_start_info(timer); | |
961 | ret = 0; | |
962 | if (timer_pending(timer)) { | |
963 | detach_timer(timer, 1); | |
964 | if (timer->expires == base->next_timer && | |
965 | !tbase_get_deferrable(timer->base)) | |
966 | base->next_timer = base->timer_jiffies; | |
967 | ret = 1; | |
968 | } | |
969 | out: | |
970 | spin_unlock_irqrestore(&base->lock, flags); | |
971 | ||
972 | return ret; | |
973 | } | |
974 | EXPORT_SYMBOL(try_to_del_timer_sync); | |
975 | ||
976 | /** | |
977 | * del_timer_sync - deactivate a timer and wait for the handler to finish. | |
978 | * @timer: the timer to be deactivated | |
979 | * | |
980 | * This function only differs from del_timer() on SMP: besides deactivating | |
981 | * the timer it also makes sure the handler has finished executing on other | |
982 | * CPUs. | |
983 | * | |
984 | * Synchronization rules: Callers must prevent restarting of the timer, | |
985 | * otherwise this function is meaningless. It must not be called from | |
986 | * interrupt contexts. The caller must not hold locks which would prevent | |
987 | * completion of the timer's handler. The timer's handler must not call | |
988 | * add_timer_on(). Upon exit the timer is not queued and the handler is | |
989 | * not running on any CPU. | |
990 | * | |
991 | * The function returns whether it has deactivated a pending timer or not. | |
992 | */ | |
993 | int del_timer_sync(struct timer_list *timer) | |
994 | { | |
995 | #ifdef CONFIG_LOCKDEP | |
996 | unsigned long flags; | |
997 | ||
998 | local_irq_save(flags); | |
999 | lock_map_acquire(&timer->lockdep_map); | |
1000 | lock_map_release(&timer->lockdep_map); | |
1001 | local_irq_restore(flags); | |
1002 | #endif | |
1003 | ||
1004 | for (;;) { | |
1005 | int ret = try_to_del_timer_sync(timer); | |
1006 | if (ret >= 0) | |
1007 | return ret; | |
1008 | cpu_relax(); | |
1009 | } | |
1010 | } | |
1011 | EXPORT_SYMBOL(del_timer_sync); | |
1012 | #endif | |
1013 | ||
1014 | static int cascade(struct tvec_base *base, struct tvec *tv, int index) | |
1015 | { | |
1016 | /* cascade all the timers from tv up one level */ | |
1017 | struct timer_list *timer, *tmp; | |
1018 | struct list_head tv_list; | |
1019 | ||
1020 | list_replace_init(tv->vec + index, &tv_list); | |
1021 | ||
1022 | /* | |
1023 | * We are removing _all_ timers from the list, so we | |
1024 | * don't have to detach them individually. | |
1025 | */ | |
1026 | list_for_each_entry_safe(timer, tmp, &tv_list, entry) { | |
1027 | BUG_ON(tbase_get_base(timer->base) != base); | |
1028 | internal_add_timer(base, timer); | |
1029 | } | |
1030 | ||
1031 | return index; | |
1032 | } | |
1033 | ||
1034 | static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long), | |
1035 | unsigned long data) | |
1036 | { | |
1037 | int preempt_count = preempt_count(); | |
1038 | ||
1039 | #ifdef CONFIG_LOCKDEP | |
1040 | /* | |
1041 | * It is permissible to free the timer from inside the | |
1042 | * function that is called from it, this we need to take into | |
1043 | * account for lockdep too. To avoid bogus "held lock freed" | |
1044 | * warnings as well as problems when looking into | |
1045 | * timer->lockdep_map, make a copy and use that here. | |
1046 | */ | |
1047 | struct lockdep_map lockdep_map = timer->lockdep_map; | |
1048 | #endif | |
1049 | /* | |
1050 | * Couple the lock chain with the lock chain at | |
1051 | * del_timer_sync() by acquiring the lock_map around the fn() | |
1052 | * call here and in del_timer_sync(). | |
1053 | */ | |
1054 | lock_map_acquire(&lockdep_map); | |
1055 | ||
1056 | trace_timer_expire_entry(timer); | |
1057 | fn(data); | |
1058 | trace_timer_expire_exit(timer); | |
1059 | ||
1060 | lock_map_release(&lockdep_map); | |
1061 | ||
1062 | if (preempt_count != preempt_count()) { | |
1063 | WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n", | |
1064 | fn, preempt_count, preempt_count()); | |
1065 | /* | |
1066 | * Restore the preempt count. That gives us a decent | |
1067 | * chance to survive and extract information. If the | |
1068 | * callback kept a lock held, bad luck, but not worse | |
1069 | * than the BUG() we had. | |
1070 | */ | |
1071 | preempt_count() = preempt_count; | |
1072 | } | |
1073 | } | |
1074 | ||
1075 | #define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK) | |
1076 | ||
1077 | /** | |
1078 | * __run_timers - run all expired timers (if any) on this CPU. | |
1079 | * @base: the timer vector to be processed. | |
1080 | * | |
1081 | * This function cascades all vectors and executes all expired timer | |
1082 | * vectors. | |
1083 | */ | |
1084 | static inline void __run_timers(struct tvec_base *base) | |
1085 | { | |
1086 | struct timer_list *timer; | |
1087 | ||
1088 | spin_lock_irq(&base->lock); | |
1089 | while (time_after_eq(jiffies, base->timer_jiffies)) { | |
1090 | struct list_head work_list; | |
1091 | struct list_head *head = &work_list; | |
1092 | int index = base->timer_jiffies & TVR_MASK; | |
1093 | ||
1094 | /* | |
1095 | * Cascade timers: | |
1096 | */ | |
1097 | if (!index && | |
1098 | (!cascade(base, &base->tv2, INDEX(0))) && | |
1099 | (!cascade(base, &base->tv3, INDEX(1))) && | |
1100 | !cascade(base, &base->tv4, INDEX(2))) | |
1101 | cascade(base, &base->tv5, INDEX(3)); | |
1102 | ++base->timer_jiffies; | |
1103 | list_replace_init(base->tv1.vec + index, &work_list); | |
1104 | while (!list_empty(head)) { | |
1105 | void (*fn)(unsigned long); | |
1106 | unsigned long data; | |
1107 | ||
1108 | timer = list_first_entry(head, struct timer_list,entry); | |
1109 | fn = timer->function; | |
1110 | data = timer->data; | |
1111 | ||
1112 | timer_stats_account_timer(timer); | |
1113 | ||
1114 | set_running_timer(base, timer); | |
1115 | detach_timer(timer, 1); | |
1116 | ||
1117 | spin_unlock_irq(&base->lock); | |
1118 | call_timer_fn(timer, fn, data); | |
1119 | spin_lock_irq(&base->lock); | |
1120 | } | |
1121 | } | |
1122 | set_running_timer(base, NULL); | |
1123 | spin_unlock_irq(&base->lock); | |
1124 | } | |
1125 | ||
1126 | #ifdef CONFIG_NO_HZ | |
1127 | /* | |
1128 | * Find out when the next timer event is due to happen. This | |
1129 | * is used on S/390 to stop all activity when a CPU is idle. | |
1130 | * This function needs to be called with interrupts disabled. | |
1131 | */ | |
1132 | static unsigned long __next_timer_interrupt(struct tvec_base *base) | |
1133 | { | |
1134 | unsigned long timer_jiffies = base->timer_jiffies; | |
1135 | unsigned long expires = timer_jiffies + NEXT_TIMER_MAX_DELTA; | |
1136 | int index, slot, array, found = 0; | |
1137 | struct timer_list *nte; | |
1138 | struct tvec *varray[4]; | |
1139 | ||
1140 | /* Look for timer events in tv1. */ | |
1141 | index = slot = timer_jiffies & TVR_MASK; | |
1142 | do { | |
1143 | list_for_each_entry(nte, base->tv1.vec + slot, entry) { | |
1144 | if (tbase_get_deferrable(nte->base)) | |
1145 | continue; | |
1146 | ||
1147 | found = 1; | |
1148 | expires = nte->expires; | |
1149 | /* Look at the cascade bucket(s)? */ | |
1150 | if (!index || slot < index) | |
1151 | goto cascade; | |
1152 | return expires; | |
1153 | } | |
1154 | slot = (slot + 1) & TVR_MASK; | |
1155 | } while (slot != index); | |
1156 | ||
1157 | cascade: | |
1158 | /* Calculate the next cascade event */ | |
1159 | if (index) | |
1160 | timer_jiffies += TVR_SIZE - index; | |
1161 | timer_jiffies >>= TVR_BITS; | |
1162 | ||
1163 | /* Check tv2-tv5. */ | |
1164 | varray[0] = &base->tv2; | |
1165 | varray[1] = &base->tv3; | |
1166 | varray[2] = &base->tv4; | |
1167 | varray[3] = &base->tv5; | |
1168 | ||
1169 | for (array = 0; array < 4; array++) { | |
1170 | struct tvec *varp = varray[array]; | |
1171 | ||
1172 | index = slot = timer_jiffies & TVN_MASK; | |
1173 | do { | |
1174 | list_for_each_entry(nte, varp->vec + slot, entry) { | |
1175 | if (tbase_get_deferrable(nte->base)) | |
1176 | continue; | |
1177 | ||
1178 | found = 1; | |
1179 | if (time_before(nte->expires, expires)) | |
1180 | expires = nte->expires; | |
1181 | } | |
1182 | /* | |
1183 | * Do we still search for the first timer or are | |
1184 | * we looking up the cascade buckets ? | |
1185 | */ | |
1186 | if (found) { | |
1187 | /* Look at the cascade bucket(s)? */ | |
1188 | if (!index || slot < index) | |
1189 | break; | |
1190 | return expires; | |
1191 | } | |
1192 | slot = (slot + 1) & TVN_MASK; | |
1193 | } while (slot != index); | |
1194 | ||
1195 | if (index) | |
1196 | timer_jiffies += TVN_SIZE - index; | |
1197 | timer_jiffies >>= TVN_BITS; | |
1198 | } | |
1199 | return expires; | |
1200 | } | |
1201 | ||
1202 | /* | |
1203 | * Check, if the next hrtimer event is before the next timer wheel | |
1204 | * event: | |
1205 | */ | |
1206 | static unsigned long cmp_next_hrtimer_event(unsigned long now, | |
1207 | unsigned long expires) | |
1208 | { | |
1209 | ktime_t hr_delta = hrtimer_get_next_event(); | |
1210 | struct timespec tsdelta; | |
1211 | unsigned long delta; | |
1212 | ||
1213 | if (hr_delta.tv64 == KTIME_MAX) | |
1214 | return expires; | |
1215 | ||
1216 | /* | |
1217 | * Expired timer available, let it expire in the next tick | |
1218 | */ | |
1219 | if (hr_delta.tv64 <= 0) | |
1220 | return now + 1; | |
1221 | ||
1222 | tsdelta = ktime_to_timespec(hr_delta); | |
1223 | delta = timespec_to_jiffies(&tsdelta); | |
1224 | ||
1225 | /* | |
1226 | * Limit the delta to the max value, which is checked in | |
1227 | * tick_nohz_stop_sched_tick(): | |
1228 | */ | |
1229 | if (delta > NEXT_TIMER_MAX_DELTA) | |
1230 | delta = NEXT_TIMER_MAX_DELTA; | |
1231 | ||
1232 | /* | |
1233 | * Take rounding errors in to account and make sure, that it | |
1234 | * expires in the next tick. Otherwise we go into an endless | |
1235 | * ping pong due to tick_nohz_stop_sched_tick() retriggering | |
1236 | * the timer softirq | |
1237 | */ | |
1238 | if (delta < 1) | |
1239 | delta = 1; | |
1240 | now += delta; | |
1241 | if (time_before(now, expires)) | |
1242 | return now; | |
1243 | return expires; | |
1244 | } | |
1245 | ||
1246 | /** | |
1247 | * get_next_timer_interrupt - return the jiffy of the next pending timer | |
1248 | * @now: current time (in jiffies) | |
1249 | */ | |
1250 | unsigned long get_next_timer_interrupt(unsigned long now) | |
1251 | { | |
1252 | struct tvec_base *base = __get_cpu_var(tvec_bases); | |
1253 | unsigned long expires; | |
1254 | ||
1255 | spin_lock(&base->lock); | |
1256 | if (time_before_eq(base->next_timer, base->timer_jiffies)) | |
1257 | base->next_timer = __next_timer_interrupt(base); | |
1258 | expires = base->next_timer; | |
1259 | spin_unlock(&base->lock); | |
1260 | ||
1261 | if (time_before_eq(expires, now)) | |
1262 | return now; | |
1263 | ||
1264 | return cmp_next_hrtimer_event(now, expires); | |
1265 | } | |
1266 | #endif | |
1267 | ||
1268 | /* | |
1269 | * Called from the timer interrupt handler to charge one tick to the current | |
1270 | * process. user_tick is 1 if the tick is user time, 0 for system. | |
1271 | */ | |
1272 | void update_process_times(int user_tick) | |
1273 | { | |
1274 | struct task_struct *p = current; | |
1275 | int cpu = smp_processor_id(); | |
1276 | ||
1277 | /* Note: this timer irq context must be accounted for as well. */ | |
1278 | account_process_tick(p, user_tick); | |
1279 | run_local_timers(); | |
1280 | rcu_check_callbacks(cpu, user_tick); | |
1281 | printk_tick(); | |
1282 | #ifdef CONFIG_IRQ_WORK | |
1283 | if (in_irq()) | |
1284 | irq_work_run(); | |
1285 | #endif | |
1286 | scheduler_tick(); | |
1287 | run_posix_cpu_timers(p); | |
1288 | } | |
1289 | ||
1290 | /* | |
1291 | * This function runs timers and the timer-tq in bottom half context. | |
1292 | */ | |
1293 | static void run_timer_softirq(struct softirq_action *h) | |
1294 | { | |
1295 | struct tvec_base *base = __get_cpu_var(tvec_bases); | |
1296 | ||
1297 | hrtimer_run_pending(); | |
1298 | ||
1299 | if (time_after_eq(jiffies, base->timer_jiffies)) | |
1300 | __run_timers(base); | |
1301 | } | |
1302 | ||
1303 | /* | |
1304 | * Called by the local, per-CPU timer interrupt on SMP. | |
1305 | */ | |
1306 | void run_local_timers(void) | |
1307 | { | |
1308 | hrtimer_run_queues(); | |
1309 | raise_softirq(TIMER_SOFTIRQ); | |
1310 | } | |
1311 | ||
1312 | /* | |
1313 | * The 64-bit jiffies value is not atomic - you MUST NOT read it | |
1314 | * without sampling the sequence number in xtime_lock. | |
1315 | * jiffies is defined in the linker script... | |
1316 | */ | |
1317 | ||
1318 | void do_timer(unsigned long ticks) | |
1319 | { | |
1320 | jiffies_64 += ticks; | |
1321 | update_wall_time(); | |
1322 | calc_global_load(); | |
1323 | } | |
1324 | ||
1325 | #ifdef __ARCH_WANT_SYS_ALARM | |
1326 | ||
1327 | /* | |
1328 | * For backwards compatibility? This can be done in libc so Alpha | |
1329 | * and all newer ports shouldn't need it. | |
1330 | */ | |
1331 | SYSCALL_DEFINE1(alarm, unsigned int, seconds) | |
1332 | { | |
1333 | return alarm_setitimer(seconds); | |
1334 | } | |
1335 | ||
1336 | #endif | |
1337 | ||
1338 | #ifndef __alpha__ | |
1339 | ||
1340 | /* | |
1341 | * The Alpha uses getxpid, getxuid, and getxgid instead. Maybe this | |
1342 | * should be moved into arch/i386 instead? | |
1343 | */ | |
1344 | ||
1345 | /** | |
1346 | * sys_getpid - return the thread group id of the current process | |
1347 | * | |
1348 | * Note, despite the name, this returns the tgid not the pid. The tgid and | |
1349 | * the pid are identical unless CLONE_THREAD was specified on clone() in | |
1350 | * which case the tgid is the same in all threads of the same group. | |
1351 | * | |
1352 | * This is SMP safe as current->tgid does not change. | |
1353 | */ | |
1354 | SYSCALL_DEFINE0(getpid) | |
1355 | { | |
1356 | return task_tgid_vnr(current); | |
1357 | } | |
1358 | ||
1359 | /* | |
1360 | * Accessing ->real_parent is not SMP-safe, it could | |
1361 | * change from under us. However, we can use a stale | |
1362 | * value of ->real_parent under rcu_read_lock(), see | |
1363 | * release_task()->call_rcu(delayed_put_task_struct). | |
1364 | */ | |
1365 | SYSCALL_DEFINE0(getppid) | |
1366 | { | |
1367 | int pid; | |
1368 | ||
1369 | rcu_read_lock(); | |
1370 | pid = task_tgid_vnr(current->real_parent); | |
1371 | rcu_read_unlock(); | |
1372 | ||
1373 | return pid; | |
1374 | } | |
1375 | ||
1376 | SYSCALL_DEFINE0(getuid) | |
1377 | { | |
1378 | /* Only we change this so SMP safe */ | |
1379 | return current_uid(); | |
1380 | } | |
1381 | ||
1382 | SYSCALL_DEFINE0(geteuid) | |
1383 | { | |
1384 | /* Only we change this so SMP safe */ | |
1385 | return current_euid(); | |
1386 | } | |
1387 | ||
1388 | SYSCALL_DEFINE0(getgid) | |
1389 | { | |
1390 | /* Only we change this so SMP safe */ | |
1391 | return current_gid(); | |
1392 | } | |
1393 | ||
1394 | SYSCALL_DEFINE0(getegid) | |
1395 | { | |
1396 | /* Only we change this so SMP safe */ | |
1397 | return current_egid(); | |
1398 | } | |
1399 | ||
1400 | #endif | |
1401 | ||
1402 | static void process_timeout(unsigned long __data) | |
1403 | { | |
1404 | wake_up_process((struct task_struct *)__data); | |
1405 | } | |
1406 | ||
1407 | /** | |
1408 | * schedule_timeout - sleep until timeout | |
1409 | * @timeout: timeout value in jiffies | |
1410 | * | |
1411 | * Make the current task sleep until @timeout jiffies have | |
1412 | * elapsed. The routine will return immediately unless | |
1413 | * the current task state has been set (see set_current_state()). | |
1414 | * | |
1415 | * You can set the task state as follows - | |
1416 | * | |
1417 | * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to | |
1418 | * pass before the routine returns. The routine will return 0 | |
1419 | * | |
1420 | * %TASK_INTERRUPTIBLE - the routine may return early if a signal is | |
1421 | * delivered to the current task. In this case the remaining time | |
1422 | * in jiffies will be returned, or 0 if the timer expired in time | |
1423 | * | |
1424 | * The current task state is guaranteed to be TASK_RUNNING when this | |
1425 | * routine returns. | |
1426 | * | |
1427 | * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule | |
1428 | * the CPU away without a bound on the timeout. In this case the return | |
1429 | * value will be %MAX_SCHEDULE_TIMEOUT. | |
1430 | * | |
1431 | * In all cases the return value is guaranteed to be non-negative. | |
1432 | */ | |
1433 | signed long __sched schedule_timeout(signed long timeout) | |
1434 | { | |
1435 | struct timer_list timer; | |
1436 | unsigned long expire; | |
1437 | ||
1438 | switch (timeout) | |
1439 | { | |
1440 | case MAX_SCHEDULE_TIMEOUT: | |
1441 | /* | |
1442 | * These two special cases are useful to be comfortable | |
1443 | * in the caller. Nothing more. We could take | |
1444 | * MAX_SCHEDULE_TIMEOUT from one of the negative value | |
1445 | * but I' d like to return a valid offset (>=0) to allow | |
1446 | * the caller to do everything it want with the retval. | |
1447 | */ | |
1448 | schedule(); | |
1449 | goto out; | |
1450 | default: | |
1451 | /* | |
1452 | * Another bit of PARANOID. Note that the retval will be | |
1453 | * 0 since no piece of kernel is supposed to do a check | |
1454 | * for a negative retval of schedule_timeout() (since it | |
1455 | * should never happens anyway). You just have the printk() | |
1456 | * that will tell you if something is gone wrong and where. | |
1457 | */ | |
1458 | if (timeout < 0) { | |
1459 | printk(KERN_ERR "schedule_timeout: wrong timeout " | |
1460 | "value %lx\n", timeout); | |
1461 | dump_stack(); | |
1462 | current->state = TASK_RUNNING; | |
1463 | goto out; | |
1464 | } | |
1465 | } | |
1466 | ||
1467 | expire = timeout + jiffies; | |
1468 | ||
1469 | setup_timer_on_stack(&timer, process_timeout, (unsigned long)current); | |
1470 | __mod_timer(&timer, expire, false, TIMER_NOT_PINNED); | |
1471 | schedule(); | |
1472 | del_singleshot_timer_sync(&timer); | |
1473 | ||
1474 | /* Remove the timer from the object tracker */ | |
1475 | destroy_timer_on_stack(&timer); | |
1476 | ||
1477 | timeout = expire - jiffies; | |
1478 | ||
1479 | out: | |
1480 | return timeout < 0 ? 0 : timeout; | |
1481 | } | |
1482 | EXPORT_SYMBOL(schedule_timeout); | |
1483 | ||
1484 | /* | |
1485 | * We can use __set_current_state() here because schedule_timeout() calls | |
1486 | * schedule() unconditionally. | |
1487 | */ | |
1488 | signed long __sched schedule_timeout_interruptible(signed long timeout) | |
1489 | { | |
1490 | __set_current_state(TASK_INTERRUPTIBLE); | |
1491 | return schedule_timeout(timeout); | |
1492 | } | |
1493 | EXPORT_SYMBOL(schedule_timeout_interruptible); | |
1494 | ||
1495 | signed long __sched schedule_timeout_killable(signed long timeout) | |
1496 | { | |
1497 | __set_current_state(TASK_KILLABLE); | |
1498 | return schedule_timeout(timeout); | |
1499 | } | |
1500 | EXPORT_SYMBOL(schedule_timeout_killable); | |
1501 | ||
1502 | signed long __sched schedule_timeout_uninterruptible(signed long timeout) | |
1503 | { | |
1504 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
1505 | return schedule_timeout(timeout); | |
1506 | } | |
1507 | EXPORT_SYMBOL(schedule_timeout_uninterruptible); | |
1508 | ||
1509 | /* Thread ID - the internal kernel "pid" */ | |
1510 | SYSCALL_DEFINE0(gettid) | |
1511 | { | |
1512 | return task_pid_vnr(current); | |
1513 | } | |
1514 | ||
1515 | /** | |
1516 | * do_sysinfo - fill in sysinfo struct | |
1517 | * @info: pointer to buffer to fill | |
1518 | */ | |
1519 | int do_sysinfo(struct sysinfo *info) | |
1520 | { | |
1521 | unsigned long mem_total, sav_total; | |
1522 | unsigned int mem_unit, bitcount; | |
1523 | struct timespec tp; | |
1524 | ||
1525 | memset(info, 0, sizeof(struct sysinfo)); | |
1526 | ||
1527 | ktime_get_ts(&tp); | |
1528 | monotonic_to_bootbased(&tp); | |
1529 | info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0); | |
1530 | ||
1531 | get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT); | |
1532 | ||
1533 | info->procs = nr_threads; | |
1534 | ||
1535 | si_meminfo(info); | |
1536 | si_swapinfo(info); | |
1537 | ||
1538 | /* | |
1539 | * If the sum of all the available memory (i.e. ram + swap) | |
1540 | * is less than can be stored in a 32 bit unsigned long then | |
1541 | * we can be binary compatible with 2.2.x kernels. If not, | |
1542 | * well, in that case 2.2.x was broken anyways... | |
1543 | * | |
1544 | * -Erik Andersen <andersee@debian.org> | |
1545 | */ | |
1546 | ||
1547 | mem_total = info->totalram + info->totalswap; | |
1548 | if (mem_total < info->totalram || mem_total < info->totalswap) | |
1549 | goto out; | |
1550 | bitcount = 0; | |
1551 | mem_unit = info->mem_unit; | |
1552 | while (mem_unit > 1) { | |
1553 | bitcount++; | |
1554 | mem_unit >>= 1; | |
1555 | sav_total = mem_total; | |
1556 | mem_total <<= 1; | |
1557 | if (mem_total < sav_total) | |
1558 | goto out; | |
1559 | } | |
1560 | ||
1561 | /* | |
1562 | * If mem_total did not overflow, multiply all memory values by | |
1563 | * info->mem_unit and set it to 1. This leaves things compatible | |
1564 | * with 2.2.x, and also retains compatibility with earlier 2.4.x | |
1565 | * kernels... | |
1566 | */ | |
1567 | ||
1568 | info->mem_unit = 1; | |
1569 | info->totalram <<= bitcount; | |
1570 | info->freeram <<= bitcount; | |
1571 | info->sharedram <<= bitcount; | |
1572 | info->bufferram <<= bitcount; | |
1573 | info->totalswap <<= bitcount; | |
1574 | info->freeswap <<= bitcount; | |
1575 | info->totalhigh <<= bitcount; | |
1576 | info->freehigh <<= bitcount; | |
1577 | ||
1578 | out: | |
1579 | return 0; | |
1580 | } | |
1581 | ||
1582 | SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info) | |
1583 | { | |
1584 | struct sysinfo val; | |
1585 | ||
1586 | do_sysinfo(&val); | |
1587 | ||
1588 | if (copy_to_user(info, &val, sizeof(struct sysinfo))) | |
1589 | return -EFAULT; | |
1590 | ||
1591 | return 0; | |
1592 | } | |
1593 | ||
1594 | static int __cpuinit init_timers_cpu(int cpu) | |
1595 | { | |
1596 | int j; | |
1597 | struct tvec_base *base; | |
1598 | static char __cpuinitdata tvec_base_done[NR_CPUS]; | |
1599 | ||
1600 | if (!tvec_base_done[cpu]) { | |
1601 | static char boot_done; | |
1602 | ||
1603 | if (boot_done) { | |
1604 | /* | |
1605 | * The APs use this path later in boot | |
1606 | */ | |
1607 | base = kmalloc_node(sizeof(*base), | |
1608 | GFP_KERNEL | __GFP_ZERO, | |
1609 | cpu_to_node(cpu)); | |
1610 | if (!base) | |
1611 | return -ENOMEM; | |
1612 | ||
1613 | /* Make sure that tvec_base is 2 byte aligned */ | |
1614 | if (tbase_get_deferrable(base)) { | |
1615 | WARN_ON(1); | |
1616 | kfree(base); | |
1617 | return -ENOMEM; | |
1618 | } | |
1619 | per_cpu(tvec_bases, cpu) = base; | |
1620 | } else { | |
1621 | /* | |
1622 | * This is for the boot CPU - we use compile-time | |
1623 | * static initialisation because per-cpu memory isn't | |
1624 | * ready yet and because the memory allocators are not | |
1625 | * initialised either. | |
1626 | */ | |
1627 | boot_done = 1; | |
1628 | base = &boot_tvec_bases; | |
1629 | } | |
1630 | tvec_base_done[cpu] = 1; | |
1631 | } else { | |
1632 | base = per_cpu(tvec_bases, cpu); | |
1633 | } | |
1634 | ||
1635 | spin_lock_init(&base->lock); | |
1636 | ||
1637 | for (j = 0; j < TVN_SIZE; j++) { | |
1638 | INIT_LIST_HEAD(base->tv5.vec + j); | |
1639 | INIT_LIST_HEAD(base->tv4.vec + j); | |
1640 | INIT_LIST_HEAD(base->tv3.vec + j); | |
1641 | INIT_LIST_HEAD(base->tv2.vec + j); | |
1642 | } | |
1643 | for (j = 0; j < TVR_SIZE; j++) | |
1644 | INIT_LIST_HEAD(base->tv1.vec + j); | |
1645 | ||
1646 | base->timer_jiffies = jiffies; | |
1647 | base->next_timer = base->timer_jiffies; | |
1648 | return 0; | |
1649 | } | |
1650 | ||
1651 | #ifdef CONFIG_HOTPLUG_CPU | |
1652 | static void migrate_timer_list(struct tvec_base *new_base, struct list_head *head) | |
1653 | { | |
1654 | struct timer_list *timer; | |
1655 | ||
1656 | while (!list_empty(head)) { | |
1657 | timer = list_first_entry(head, struct timer_list, entry); | |
1658 | detach_timer(timer, 0); | |
1659 | timer_set_base(timer, new_base); | |
1660 | if (time_before(timer->expires, new_base->next_timer) && | |
1661 | !tbase_get_deferrable(timer->base)) | |
1662 | new_base->next_timer = timer->expires; | |
1663 | internal_add_timer(new_base, timer); | |
1664 | } | |
1665 | } | |
1666 | ||
1667 | static void __cpuinit migrate_timers(int cpu) | |
1668 | { | |
1669 | struct tvec_base *old_base; | |
1670 | struct tvec_base *new_base; | |
1671 | int i; | |
1672 | ||
1673 | BUG_ON(cpu_online(cpu)); | |
1674 | old_base = per_cpu(tvec_bases, cpu); | |
1675 | new_base = get_cpu_var(tvec_bases); | |
1676 | /* | |
1677 | * The caller is globally serialized and nobody else | |
1678 | * takes two locks at once, deadlock is not possible. | |
1679 | */ | |
1680 | spin_lock_irq(&new_base->lock); | |
1681 | spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING); | |
1682 | ||
1683 | BUG_ON(old_base->running_timer); | |
1684 | ||
1685 | for (i = 0; i < TVR_SIZE; i++) | |
1686 | migrate_timer_list(new_base, old_base->tv1.vec + i); | |
1687 | for (i = 0; i < TVN_SIZE; i++) { | |
1688 | migrate_timer_list(new_base, old_base->tv2.vec + i); | |
1689 | migrate_timer_list(new_base, old_base->tv3.vec + i); | |
1690 | migrate_timer_list(new_base, old_base->tv4.vec + i); | |
1691 | migrate_timer_list(new_base, old_base->tv5.vec + i); | |
1692 | } | |
1693 | ||
1694 | spin_unlock(&old_base->lock); | |
1695 | spin_unlock_irq(&new_base->lock); | |
1696 | put_cpu_var(tvec_bases); | |
1697 | } | |
1698 | #endif /* CONFIG_HOTPLUG_CPU */ | |
1699 | ||
1700 | static int __cpuinit timer_cpu_notify(struct notifier_block *self, | |
1701 | unsigned long action, void *hcpu) | |
1702 | { | |
1703 | long cpu = (long)hcpu; | |
1704 | int err; | |
1705 | ||
1706 | switch(action) { | |
1707 | case CPU_UP_PREPARE: | |
1708 | case CPU_UP_PREPARE_FROZEN: | |
1709 | err = init_timers_cpu(cpu); | |
1710 | if (err < 0) | |
1711 | return notifier_from_errno(err); | |
1712 | break; | |
1713 | #ifdef CONFIG_HOTPLUG_CPU | |
1714 | case CPU_DEAD: | |
1715 | case CPU_DEAD_FROZEN: | |
1716 | migrate_timers(cpu); | |
1717 | break; | |
1718 | #endif | |
1719 | default: | |
1720 | break; | |
1721 | } | |
1722 | return NOTIFY_OK; | |
1723 | } | |
1724 | ||
1725 | static struct notifier_block __cpuinitdata timers_nb = { | |
1726 | .notifier_call = timer_cpu_notify, | |
1727 | }; | |
1728 | ||
1729 | ||
1730 | void __init init_timers(void) | |
1731 | { | |
1732 | int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE, | |
1733 | (void *)(long)smp_processor_id()); | |
1734 | ||
1735 | init_timer_stats(); | |
1736 | ||
1737 | BUG_ON(err != NOTIFY_OK); | |
1738 | register_cpu_notifier(&timers_nb); | |
1739 | open_softirq(TIMER_SOFTIRQ, run_timer_softirq); | |
1740 | } | |
1741 | ||
1742 | /** | |
1743 | * msleep - sleep safely even with waitqueue interruptions | |
1744 | * @msecs: Time in milliseconds to sleep for | |
1745 | */ | |
1746 | void msleep(unsigned int msecs) | |
1747 | { | |
1748 | unsigned long timeout = msecs_to_jiffies(msecs) + 1; | |
1749 | ||
1750 | while (timeout) | |
1751 | timeout = schedule_timeout_uninterruptible(timeout); | |
1752 | } | |
1753 | ||
1754 | EXPORT_SYMBOL(msleep); | |
1755 | ||
1756 | /** | |
1757 | * msleep_interruptible - sleep waiting for signals | |
1758 | * @msecs: Time in milliseconds to sleep for | |
1759 | */ | |
1760 | unsigned long msleep_interruptible(unsigned int msecs) | |
1761 | { | |
1762 | unsigned long timeout = msecs_to_jiffies(msecs) + 1; | |
1763 | ||
1764 | while (timeout && !signal_pending(current)) | |
1765 | timeout = schedule_timeout_interruptible(timeout); | |
1766 | return jiffies_to_msecs(timeout); | |
1767 | } | |
1768 | ||
1769 | EXPORT_SYMBOL(msleep_interruptible); | |
1770 | ||
1771 | static int __sched do_usleep_range(unsigned long min, unsigned long max) | |
1772 | { | |
1773 | ktime_t kmin; | |
1774 | unsigned long delta; | |
1775 | ||
1776 | kmin = ktime_set(0, min * NSEC_PER_USEC); | |
1777 | delta = (max - min) * NSEC_PER_USEC; | |
1778 | return schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL); | |
1779 | } | |
1780 | ||
1781 | /** | |
1782 | * usleep_range - Drop in replacement for udelay where wakeup is flexible | |
1783 | * @min: Minimum time in usecs to sleep | |
1784 | * @max: Maximum time in usecs to sleep | |
1785 | */ | |
1786 | void usleep_range(unsigned long min, unsigned long max) | |
1787 | { | |
1788 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
1789 | do_usleep_range(min, max); | |
1790 | } | |
1791 | EXPORT_SYMBOL(usleep_range); |