Branch data Line data Source code
1 : : /*
2 : : * linux/kernel/timer.c
3 : : *
4 : : * Kernel internal timers
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/export.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/sched/sysctl.h>
43 : : #include <linux/slab.h>
44 : : #include <linux/compat.h>
45 : :
46 : : #include <asm/uaccess.h>
47 : : #include <asm/unistd.h>
48 : : #include <asm/div64.h>
49 : : #include <asm/timex.h>
50 : : #include <asm/io.h>
51 : :
52 : : #define CREATE_TRACE_POINTS
53 : : #include <trace/events/timer.h>
54 : :
55 : : u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
56 : :
57 : : EXPORT_SYMBOL(jiffies_64);
58 : :
59 : : /*
60 : : * per-CPU timer vector definitions:
61 : : */
62 : : #define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6)
63 : : #define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8)
64 : : #define TVN_SIZE (1 << TVN_BITS)
65 : : #define TVR_SIZE (1 << TVR_BITS)
66 : : #define TVN_MASK (TVN_SIZE - 1)
67 : : #define TVR_MASK (TVR_SIZE - 1)
68 : : #define MAX_TVAL ((unsigned long)((1ULL << (TVR_BITS + 4*TVN_BITS)) - 1))
69 : :
70 : : struct tvec {
71 : : struct list_head vec[TVN_SIZE];
72 : : };
73 : :
74 : : struct tvec_root {
75 : : struct list_head vec[TVR_SIZE];
76 : : };
77 : :
78 : : struct tvec_base {
79 : : spinlock_t lock;
80 : : struct timer_list *running_timer;
81 : : unsigned long timer_jiffies;
82 : : unsigned long next_timer;
83 : : unsigned long active_timers;
84 : : struct tvec_root tv1;
85 : : struct tvec tv2;
86 : : struct tvec tv3;
87 : : struct tvec tv4;
88 : : struct tvec tv5;
89 : : } ____cacheline_aligned;
90 : :
91 : : struct tvec_base boot_tvec_bases;
92 : : EXPORT_SYMBOL(boot_tvec_bases);
93 : : static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases;
94 : :
95 : : /* Functions below help us manage 'deferrable' flag */
96 : : static inline unsigned int tbase_get_deferrable(struct tvec_base *base)
97 : : {
98 : 3807948 : return ((unsigned int)(unsigned long)base & TIMER_DEFERRABLE);
99 : : }
100 : :
101 : : static inline unsigned int tbase_get_irqsafe(struct tvec_base *base)
102 : : {
103 : 1105127 : return ((unsigned int)(unsigned long)base & TIMER_IRQSAFE);
104 : : }
105 : :
106 : : static inline struct tvec_base *tbase_get_base(struct tvec_base *base)
107 : : {
108 : 1808232 : return ((struct tvec_base *)((unsigned long)base & ~TIMER_FLAG_MASK));
109 : : }
110 : :
111 : : static inline void
112 : : timer_set_base(struct timer_list *timer, struct tvec_base *new_base)
113 : : {
114 : 149844 : unsigned long flags = (unsigned long)timer->base & TIMER_FLAG_MASK;
115 : :
116 : 44772 : timer->base = (struct tvec_base *)((unsigned long)(new_base) | flags);
117 : : }
118 : :
119 : 0 : static unsigned long round_jiffies_common(unsigned long j, int cpu,
120 : : bool force_up)
121 : : {
122 : : int rem;
123 : : unsigned long original = j;
124 : :
125 : : /*
126 : : * We don't want all cpus firing their timers at once hitting the
127 : : * same lock or cachelines, so we skew each extra cpu with an extra
128 : : * 3 jiffies. This 3 jiffies came originally from the mm/ code which
129 : : * already did this.
130 : : * The skew is done by adding 3*cpunr, then round, then subtract this
131 : : * extra offset again.
132 : : */
133 : 560397 : j += cpu * 3;
134 : :
135 : 560397 : rem = j % HZ;
136 : :
137 : : /*
138 : : * If the target jiffie is just after a whole second (which can happen
139 : : * due to delays of the timer irq, long irq off times etc etc) then
140 : : * we should round down to the whole second, not up. Use 1/4th second
141 : : * as cutoff for this rounding as an extreme upper bound for this.
142 : : * But never round down if @force_up is set.
143 : : */
144 [ + + ]: 560397 : if (rem < HZ/4 && !force_up) /* round down */
145 : 101661 : j = j - rem;
146 : : else /* round up */
147 : 458736 : j = j - rem + HZ;
148 : :
149 : : /* now that we have rounded, subtract the extra skew again */
150 : 560397 : j -= cpu * 3;
151 : :
152 : : /*
153 : : * Make sure j is still in the future. Otherwise return the
154 : : * unmodified value.
155 : : */
156 [ - + ]: 560397 : return time_is_after_jiffies(j) ? j : original;
157 : : }
158 : :
159 : : /**
160 : : * __round_jiffies - function to round jiffies to a full second
161 : : * @j: the time in (absolute) jiffies that should be rounded
162 : : * @cpu: the processor number on which the timeout will happen
163 : : *
164 : : * __round_jiffies() rounds an absolute time in the future (in jiffies)
165 : : * up or down to (approximately) full seconds. This is useful for timers
166 : : * for which the exact time they fire does not matter too much, as long as
167 : : * they fire approximately every X seconds.
168 : : *
169 : : * By rounding these timers to whole seconds, all such timers will fire
170 : : * at the same time, rather than at various times spread out. The goal
171 : : * of this is to have the CPU wake up less, which saves power.
172 : : *
173 : : * The exact rounding is skewed for each processor to avoid all
174 : : * processors firing at the exact same time, which could lead
175 : : * to lock contention or spurious cache line bouncing.
176 : : *
177 : : * The return value is the rounded version of the @j parameter.
178 : : */
179 : 0 : unsigned long __round_jiffies(unsigned long j, int cpu)
180 : : {
181 : 0 : return round_jiffies_common(j, cpu, false);
182 : : }
183 : : EXPORT_SYMBOL_GPL(__round_jiffies);
184 : :
185 : : /**
186 : : * __round_jiffies_relative - function to round jiffies to a full second
187 : : * @j: the time in (relative) jiffies that should be rounded
188 : : * @cpu: the processor number on which the timeout will happen
189 : : *
190 : : * __round_jiffies_relative() rounds a time delta in the future (in jiffies)
191 : : * up or down to (approximately) full seconds. This is useful for timers
192 : : * for which the exact time they fire does not matter too much, as long as
193 : : * they fire approximately every X seconds.
194 : : *
195 : : * By rounding these timers to whole seconds, all such timers will fire
196 : : * at the same time, rather than at various times spread out. The goal
197 : : * of this is to have the CPU wake up less, which saves power.
198 : : *
199 : : * The exact rounding is skewed for each processor to avoid all
200 : : * processors firing at the exact same time, which could lead
201 : : * to lock contention or spurious cache line bouncing.
202 : : *
203 : : * The return value is the rounded version of the @j parameter.
204 : : */
205 : 0 : unsigned long __round_jiffies_relative(unsigned long j, int cpu)
206 : : {
207 : 138164 : unsigned long j0 = jiffies;
208 : :
209 : : /* Use j0 because jiffies might change while we run */
210 : 138164 : return round_jiffies_common(j + j0, cpu, false) - j0;
211 : : }
212 : : EXPORT_SYMBOL_GPL(__round_jiffies_relative);
213 : :
214 : : /**
215 : : * round_jiffies - function to round jiffies to a full second
216 : : * @j: the time in (absolute) jiffies that should be rounded
217 : : *
218 : : * round_jiffies() rounds an absolute time in the future (in jiffies)
219 : : * up or down to (approximately) full seconds. This is useful for timers
220 : : * for which the exact time they fire does not matter too much, as long as
221 : : * they fire approximately every X seconds.
222 : : *
223 : : * By rounding these timers to whole seconds, all such timers will fire
224 : : * at the same time, rather than at various times spread out. The goal
225 : : * of this is to have the CPU wake up less, which saves power.
226 : : *
227 : : * The return value is the rounded version of the @j parameter.
228 : : */
229 : 0 : unsigned long round_jiffies(unsigned long j)
230 : : {
231 : 0 : return round_jiffies_common(j, raw_smp_processor_id(), false);
232 : : }
233 : : EXPORT_SYMBOL_GPL(round_jiffies);
234 : :
235 : : /**
236 : : * round_jiffies_relative - function to round jiffies to a full second
237 : : * @j: the time in (relative) jiffies that should be rounded
238 : : *
239 : : * round_jiffies_relative() rounds a time delta in the future (in jiffies)
240 : : * up or down to (approximately) full seconds. This is useful for timers
241 : : * for which the exact time they fire does not matter too much, as long as
242 : : * they fire approximately every X seconds.
243 : : *
244 : : * By rounding these timers to whole seconds, all such timers will fire
245 : : * at the same time, rather than at various times spread out. The goal
246 : : * of this is to have the CPU wake up less, which saves power.
247 : : *
248 : : * The return value is the rounded version of the @j parameter.
249 : : */
250 : 0 : unsigned long round_jiffies_relative(unsigned long j)
251 : : {
252 : 275983 : return __round_jiffies_relative(j, raw_smp_processor_id());
253 : : }
254 : : EXPORT_SYMBOL_GPL(round_jiffies_relative);
255 : :
256 : : /**
257 : : * __round_jiffies_up - function to round jiffies up to a full second
258 : : * @j: the time in (absolute) jiffies that should be rounded
259 : : * @cpu: the processor number on which the timeout will happen
260 : : *
261 : : * This is the same as __round_jiffies() except that it will never
262 : : * round down. This is useful for timeouts for which the exact time
263 : : * of firing does not matter too much, as long as they don't fire too
264 : : * early.
265 : : */
266 : 0 : unsigned long __round_jiffies_up(unsigned long j, int cpu)
267 : : {
268 : 0 : return round_jiffies_common(j, cpu, true);
269 : : }
270 : : EXPORT_SYMBOL_GPL(__round_jiffies_up);
271 : :
272 : : /**
273 : : * __round_jiffies_up_relative - function to round jiffies up to a full second
274 : : * @j: the time in (relative) jiffies that should be rounded
275 : : * @cpu: the processor number on which the timeout will happen
276 : : *
277 : : * This is the same as __round_jiffies_relative() except that it will never
278 : : * round down. This is useful for timeouts for which the exact time
279 : : * of firing does not matter too much, as long as they don't fire too
280 : : * early.
281 : : */
282 : 0 : unsigned long __round_jiffies_up_relative(unsigned long j, int cpu)
283 : : {
284 : 0 : unsigned long j0 = jiffies;
285 : :
286 : : /* Use j0 because jiffies might change while we run */
287 : 0 : return round_jiffies_common(j + j0, cpu, true) - j0;
288 : : }
289 : : EXPORT_SYMBOL_GPL(__round_jiffies_up_relative);
290 : :
291 : : /**
292 : : * round_jiffies_up - function to round jiffies up to a full second
293 : : * @j: the time in (absolute) jiffies that should be rounded
294 : : *
295 : : * This is the same as round_jiffies() except that it will never
296 : : * round down. This is useful for timeouts for which the exact time
297 : : * of firing does not matter too much, as long as they don't fire too
298 : : * early.
299 : : */
300 : 0 : unsigned long round_jiffies_up(unsigned long j)
301 : : {
302 : 422236 : return round_jiffies_common(j, raw_smp_processor_id(), true);
303 : : }
304 : : EXPORT_SYMBOL_GPL(round_jiffies_up);
305 : :
306 : : /**
307 : : * round_jiffies_up_relative - function to round jiffies up to a full second
308 : : * @j: the time in (relative) jiffies that should be rounded
309 : : *
310 : : * This is the same as round_jiffies_relative() except that it will never
311 : : * round down. This is useful for timeouts for which the exact time
312 : : * of firing does not matter too much, as long as they don't fire too
313 : : * early.
314 : : */
315 : 0 : unsigned long round_jiffies_up_relative(unsigned long j)
316 : : {
317 : 0 : return __round_jiffies_up_relative(j, raw_smp_processor_id());
318 : : }
319 : : EXPORT_SYMBOL_GPL(round_jiffies_up_relative);
320 : :
321 : : /**
322 : : * set_timer_slack - set the allowed slack for a timer
323 : : * @timer: the timer to be modified
324 : : * @slack_hz: the amount of time (in jiffies) allowed for rounding
325 : : *
326 : : * Set the amount of time, in jiffies, that a certain timer has
327 : : * in terms of slack. By setting this value, the timer subsystem
328 : : * will schedule the actual timer somewhere between
329 : : * the time mod_timer() asks for, and that time plus the slack.
330 : : *
331 : : * By setting the slack to -1, a percentage of the delay is used
332 : : * instead.
333 : : */
334 : 0 : void set_timer_slack(struct timer_list *timer, int slack_hz)
335 : : {
336 : 526 : timer->slack = slack_hz;
337 : 526 : }
338 : : EXPORT_SYMBOL_GPL(set_timer_slack);
339 : :
340 : : static void
341 : 0 : __internal_add_timer(struct tvec_base *base, struct timer_list *timer)
342 : : {
343 : 1302804 : unsigned long expires = timer->expires;
344 : 1302804 : unsigned long idx = expires - base->timer_jiffies;
345 : : struct list_head *vec;
346 : :
347 [ + + ]: 1302804 : if (idx < TVR_SIZE) {
348 : 1217490 : int i = expires & TVR_MASK;
349 : 1217490 : vec = base->tv1.vec + i;
350 [ + + ]: 85314 : } else if (idx < 1 << (TVR_BITS + TVN_BITS)) {
351 : 74575 : int i = (expires >> TVR_BITS) & TVN_MASK;
352 : 74575 : vec = base->tv2.vec + i;
353 [ + + ]: 10739 : } else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) {
354 : 10495 : int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK;
355 : 10495 : vec = base->tv3.vec + i;
356 [ + + ]: 244 : } else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) {
357 : 1 : int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK;
358 : 1 : vec = base->tv4.vec + i;
359 [ + - ]: 243 : } else if ((signed long) idx < 0) {
360 : : /*
361 : : * Can happen if you add a timer with expires == jiffies,
362 : : * or you set a timer to go off in the past
363 : : */
364 : 243 : vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK);
365 : : } else {
366 : : int i;
367 : : /* If the timeout is larger than MAX_TVAL (on 64-bit
368 : : * architectures or with CONFIG_BASE_SMALL=1) then we
369 : : * use the maximum timeout.
370 : : */
371 : : if (idx > MAX_TVAL) {
372 : : idx = MAX_TVAL;
373 : : expires = idx + base->timer_jiffies;
374 : : }
375 : 0 : i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK;
376 : 0 : vec = base->tv5.vec + i;
377 : : }
378 : : /*
379 : : * Timers are FIFO:
380 : : */
381 : 1302804 : list_add_tail(&timer->entry, vec);
382 : 1302804 : }
383 : :
384 : 0 : static void internal_add_timer(struct tvec_base *base, struct timer_list *timer)
385 : : {
386 : 1283219 : __internal_add_timer(base, timer);
387 : : /*
388 : : * Update base->active_timers and base->next_timer
389 : : */
390 [ + ]: 1283200 : if (!tbase_get_deferrable(timer->base)) {
391 [ + + ]: 2321493 : if (time_before(timer->expires, base->next_timer))
392 : 144211 : base->next_timer = timer->expires;
393 : 1038274 : base->active_timers++;
394 : : }
395 : 0 : }
396 : :
397 : : #ifdef CONFIG_TIMER_STATS
398 : 0 : void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr)
399 : : {
400 [ # # ]: 0 : if (timer->start_site)
401 : 0 : return;
402 : :
403 : 0 : timer->start_site = addr;
404 : 0 : memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
405 : 0 : timer->start_pid = current->pid;
406 : : }
407 : :
408 : 0 : static void timer_stats_account_timer(struct timer_list *timer)
409 : : {
410 : : unsigned int flag = 0;
411 : :
412 [ - + ]: 1104596 : if (likely(!timer->start_site))
413 : 1104596 : return;
414 [ # # ]: 0 : if (unlikely(tbase_get_deferrable(timer->base)))
415 : : flag |= TIMER_STATS_FLAG_DEFERRABLE;
416 : :
417 : 0 : timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
418 : 0 : 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 : : static void *timer_debug_hint(void *addr)
430 : : {
431 : : return ((struct timer_list *) addr)->function;
432 : : }
433 : :
434 : : /*
435 : : * fixup_init is called when:
436 : : * - an active object is initialized
437 : : */
438 : : static int timer_fixup_init(void *addr, enum debug_obj_state state)
439 : : {
440 : : struct timer_list *timer = addr;
441 : :
442 : : switch (state) {
443 : : case ODEBUG_STATE_ACTIVE:
444 : : del_timer_sync(timer);
445 : : debug_object_init(timer, &timer_debug_descr);
446 : : return 1;
447 : : default:
448 : : return 0;
449 : : }
450 : : }
451 : :
452 : : /* Stub timer callback for improperly used timers. */
453 : : static void stub_timer(unsigned long data)
454 : : {
455 : : WARN_ON(1);
456 : : }
457 : :
458 : : /*
459 : : * fixup_activate is called when:
460 : : * - an active object is activated
461 : : * - an unknown object is activated (might be a statically initialized object)
462 : : */
463 : : static int timer_fixup_activate(void *addr, enum debug_obj_state state)
464 : : {
465 : : struct timer_list *timer = addr;
466 : :
467 : : switch (state) {
468 : :
469 : : case ODEBUG_STATE_NOTAVAILABLE:
470 : : /*
471 : : * This is not really a fixup. The timer was
472 : : * statically initialized. We just make sure that it
473 : : * is tracked in the object tracker.
474 : : */
475 : : if (timer->entry.next == NULL &&
476 : : timer->entry.prev == TIMER_ENTRY_STATIC) {
477 : : debug_object_init(timer, &timer_debug_descr);
478 : : debug_object_activate(timer, &timer_debug_descr);
479 : : return 0;
480 : : } else {
481 : : setup_timer(timer, stub_timer, 0);
482 : : return 1;
483 : : }
484 : : return 0;
485 : :
486 : : case ODEBUG_STATE_ACTIVE:
487 : : WARN_ON(1);
488 : :
489 : : default:
490 : : return 0;
491 : : }
492 : : }
493 : :
494 : : /*
495 : : * fixup_free is called when:
496 : : * - an active object is freed
497 : : */
498 : : static int timer_fixup_free(void *addr, enum debug_obj_state state)
499 : : {
500 : : struct timer_list *timer = addr;
501 : :
502 : : switch (state) {
503 : : case ODEBUG_STATE_ACTIVE:
504 : : del_timer_sync(timer);
505 : : debug_object_free(timer, &timer_debug_descr);
506 : : return 1;
507 : : default:
508 : : return 0;
509 : : }
510 : : }
511 : :
512 : : /*
513 : : * fixup_assert_init is called when:
514 : : * - an untracked/uninit-ed object is found
515 : : */
516 : : static int timer_fixup_assert_init(void *addr, enum debug_obj_state state)
517 : : {
518 : : struct timer_list *timer = addr;
519 : :
520 : : switch (state) {
521 : : case ODEBUG_STATE_NOTAVAILABLE:
522 : : if (timer->entry.prev == TIMER_ENTRY_STATIC) {
523 : : /*
524 : : * This is not really a fixup. The timer was
525 : : * statically initialized. We just make sure that it
526 : : * is tracked in the object tracker.
527 : : */
528 : : debug_object_init(timer, &timer_debug_descr);
529 : : return 0;
530 : : } else {
531 : : setup_timer(timer, stub_timer, 0);
532 : : return 1;
533 : : }
534 : : default:
535 : : return 0;
536 : : }
537 : : }
538 : :
539 : : static struct debug_obj_descr timer_debug_descr = {
540 : : .name = "timer_list",
541 : : .debug_hint = timer_debug_hint,
542 : : .fixup_init = timer_fixup_init,
543 : : .fixup_activate = timer_fixup_activate,
544 : : .fixup_free = timer_fixup_free,
545 : : .fixup_assert_init = timer_fixup_assert_init,
546 : : };
547 : :
548 : : static inline void debug_timer_init(struct timer_list *timer)
549 : : {
550 : : debug_object_init(timer, &timer_debug_descr);
551 : : }
552 : :
553 : : static inline void debug_timer_activate(struct timer_list *timer)
554 : : {
555 : : debug_object_activate(timer, &timer_debug_descr);
556 : : }
557 : :
558 : : static inline void debug_timer_deactivate(struct timer_list *timer)
559 : : {
560 : : debug_object_deactivate(timer, &timer_debug_descr);
561 : : }
562 : :
563 : : static inline void debug_timer_free(struct timer_list *timer)
564 : : {
565 : : debug_object_free(timer, &timer_debug_descr);
566 : : }
567 : :
568 : : static inline void debug_timer_assert_init(struct timer_list *timer)
569 : : {
570 : : debug_object_assert_init(timer, &timer_debug_descr);
571 : : }
572 : :
573 : : static void do_init_timer(struct timer_list *timer, unsigned int flags,
574 : : const char *name, struct lock_class_key *key);
575 : :
576 : : void init_timer_on_stack_key(struct timer_list *timer, unsigned int flags,
577 : : const char *name, struct lock_class_key *key)
578 : : {
579 : : debug_object_init_on_stack(timer, &timer_debug_descr);
580 : : do_init_timer(timer, flags, name, key);
581 : : }
582 : : EXPORT_SYMBOL_GPL(init_timer_on_stack_key);
583 : :
584 : : void destroy_timer_on_stack(struct timer_list *timer)
585 : : {
586 : : debug_object_free(timer, &timer_debug_descr);
587 : : }
588 : : EXPORT_SYMBOL_GPL(destroy_timer_on_stack);
589 : :
590 : : #else
591 : : static inline void debug_timer_init(struct timer_list *timer) { }
592 : : static inline void debug_timer_activate(struct timer_list *timer) { }
593 : : static inline void debug_timer_deactivate(struct timer_list *timer) { }
594 : : static inline void debug_timer_assert_init(struct timer_list *timer) { }
595 : : #endif
596 : :
597 : : static inline void debug_init(struct timer_list *timer)
598 : : {
599 : : debug_timer_init(timer);
600 : : trace_timer_init(timer);
601 : : }
602 : :
603 : : static inline void
604 : : debug_activate(struct timer_list *timer, unsigned long expires)
605 : : {
606 : : debug_timer_activate(timer);
607 : : trace_timer_start(timer, expires);
608 : : }
609 : :
610 : : static inline void debug_deactivate(struct timer_list *timer)
611 : : {
612 : : debug_timer_deactivate(timer);
613 : : trace_timer_cancel(timer);
614 : : }
615 : :
616 : : static inline void debug_assert_init(struct timer_list *timer)
617 : : {
618 : : debug_timer_assert_init(timer);
619 : : }
620 : :
621 : 1384183 : static void do_init_timer(struct timer_list *timer, unsigned int flags,
622 : : const char *name, struct lock_class_key *key)
623 : : {
624 : 2768366 : struct tvec_base *base = __raw_get_cpu_var(tvec_bases);
625 : :
626 : 1384183 : timer->entry.next = NULL;
627 : 1384183 : timer->base = (void *)((unsigned long)base | flags);
628 : 1384183 : timer->slack = -1;
629 : : #ifdef CONFIG_TIMER_STATS
630 : 1384183 : timer->start_site = NULL;
631 : 1384183 : timer->start_pid = -1;
632 : 1384183 : memset(timer->start_comm, 0, TASK_COMM_LEN);
633 : : #endif
634 : : lockdep_init_map(&timer->lockdep_map, name, key, 0);
635 : 1393314 : }
636 : :
637 : : /**
638 : : * init_timer_key - initialize a timer
639 : : * @timer: the timer to be initialized
640 : : * @flags: timer flags
641 : : * @name: name of the timer
642 : : * @key: lockdep class key of the fake lock used for tracking timer
643 : : * sync lock dependencies
644 : : *
645 : : * init_timer_key() must be done to a timer prior calling *any* of the
646 : : * other timer functions.
647 : : */
648 : 0 : void init_timer_key(struct timer_list *timer, unsigned int flags,
649 : : const char *name, struct lock_class_key *key)
650 : : {
651 : : debug_init(timer);
652 : 1379136 : do_init_timer(timer, flags, name, key);
653 : 1393647 : }
654 : : EXPORT_SYMBOL(init_timer_key);
655 : :
656 : : static inline void detach_timer(struct timer_list *timer, bool clear_pending)
657 : : {
658 : : struct list_head *entry = &timer->entry;
659 : :
660 : : debug_deactivate(timer);
661 : :
662 : 1242756 : __list_del(entry->prev, entry->next);
663 [ + + ]: 176874 : if (clear_pending)
664 : 141477 : entry->next = NULL;
665 : 1242756 : entry->prev = LIST_POISON2;
666 : : }
667 : :
668 : : static inline void
669 : : detach_expired_timer(struct timer_list *timer, struct tvec_base *base)
670 : : {
671 : : detach_timer(timer, true);
672 [ + + ]: 1105755 : if (!tbase_get_deferrable(timer->base))
673 : 924530 : base->active_timers--;
674 : : }
675 : :
676 : 0 : static int detach_if_pending(struct timer_list *timer, struct tvec_base *base,
677 : : bool clear_pending)
678 : : {
679 [ + + ]: 1785930 : if (!timer_pending(timer))
680 : : return 0;
681 : :
682 : : detach_timer(timer, clear_pending);
683 [ + + ]: 176874 : if (!tbase_get_deferrable(timer->base)) {
684 : 113175 : base->active_timers--;
685 [ + + ]: 113175 : if (timer->expires == base->next_timer)
686 : 59084 : base->next_timer = base->timer_jiffies;
687 : : }
688 : : return 1;
689 : : }
690 : :
691 : : /*
692 : : * We are using hashed locking: holding per_cpu(tvec_bases).lock
693 : : * means that all timers which are tied to this base via timer->base are
694 : : * locked, and the base itself is locked too.
695 : : *
696 : : * So __run_timers/migrate_timers can safely modify all timers which could
697 : : * be found on ->tvX lists.
698 : : *
699 : : * When the timer's base is locked, and the timer removed from list, it is
700 : : * possible to set timer->base = NULL and drop the lock: the timer remains
701 : : * locked.
702 : : */
703 : 1788637 : static struct tvec_base *lock_timer_base(struct timer_list *timer,
704 : : unsigned long *flags)
705 : : __acquires(timer->base->lock)
706 : : {
707 : : struct tvec_base *base;
708 : :
709 : : for (;;) {
710 : 1788637 : struct tvec_base *prelock_base = timer->base;
711 : : base = tbase_get_base(prelock_base);
712 [ + + ]: 1788637 : if (likely(base != NULL)) {
713 : 1788628 : spin_lock_irqsave(&base->lock, *flags);
714 [ + - ]: 1788649 : if (likely(prelock_base == timer->base))
715 : 1788649 : return base;
716 : : /* The timer has migrated to another CPU */
717 : : spin_unlock_irqrestore(&base->lock, *flags);
718 : : }
719 : 0 : cpu_relax();
720 : : }
721 : : }
722 : :
723 : : static inline int
724 : : __mod_timer(struct timer_list *timer, unsigned long expires,
725 : : bool pending_only, int pinned)
726 : : {
727 : : struct tvec_base *base, *new_base;
728 : : unsigned long flags;
729 : : int ret = 0 , cpu;
730 : :
731 : : timer_stats_timer_set_start_info(timer);
732 [ - + ][ # # ]: 1183001 : BUG_ON(!timer->function);
[ - + ][ # # ]
733 : :
734 : 1183001 : base = lock_timer_base(timer, &flags);
735 : :
736 : 1183001 : ret = detach_if_pending(timer, base, false);
737 [ # # ]: 0 : if (!ret && pending_only)
738 : : goto out_unlock;
739 : :
740 : : debug_activate(timer, expires);
741 : :
742 : 1182992 : cpu = smp_processor_id();
743 : :
744 : : #if defined(CONFIG_NO_HZ_COMMON) && defined(CONFIG_SMP)
745 [ + + ][ - + ]: 1182992 : if (!pinned && get_sysctl_timer_migration() && idle_cpu(cpu))
[ + ][ + + ]
[ # # ][ # # ]
746 : 256845 : cpu = get_nohz_timer_target();
747 : : #endif
748 : 1182989 : new_base = per_cpu(tvec_bases, cpu);
749 : :
750 [ - + ][ # # ]: 1182989 : if (base != new_base) {
[ + + ][ # # ]
751 : : /*
752 : : * We are trying to schedule the timer on the local CPU.
753 : : * However we can't change timer's base while it is running,
754 : : * otherwise del_timer_sync() can't detect that the timer's
755 : : * handler yet has not finished. This also guarantees that
756 : : * the timer is serialized wrt itself.
757 : : */
758 [ # # ][ # # ]: 128692 : if (likely(base->running_timer != timer)) {
[ + + ][ # # ]
759 : : /* See the comment in lock_timer_base() */
760 : : timer_set_base(timer, NULL);
761 : : spin_unlock(&base->lock);
762 : : base = new_base;
763 : : spin_lock(&base->lock);
764 : : timer_set_base(timer, base);
765 : : }
766 : : }
767 : :
768 : 1182989 : timer->expires = expires;
769 : 1182989 : internal_add_timer(base, timer);
770 : :
771 : : out_unlock:
772 : 1183002 : spin_unlock_irqrestore(&base->lock, flags);
773 : :
774 : : return ret;
775 : : }
776 : :
777 : : /**
778 : : * mod_timer_pending - modify a pending timer's timeout
779 : : * @timer: the pending timer to be modified
780 : : * @expires: new timeout in jiffies
781 : : *
782 : : * mod_timer_pending() is the same for pending timers as mod_timer(),
783 : : * but will not re-activate and modify already deleted timers.
784 : : *
785 : : * It is useful for unserialized use of timers.
786 : : */
787 : 0 : int mod_timer_pending(struct timer_list *timer, unsigned long expires)
788 : : {
789 : 0 : return __mod_timer(timer, expires, true, TIMER_NOT_PINNED);
790 : : }
791 : : EXPORT_SYMBOL(mod_timer_pending);
792 : :
793 : : /*
794 : : * Decide where to put the timer while taking the slack into account
795 : : *
796 : : * Algorithm:
797 : : * 1) calculate the maximum (absolute) time
798 : : * 2) calculate the highest bit where the expires and new max are different
799 : : * 3) use this bit to make a mask
800 : : * 4) use the bitmask to round down the maximum time, so that all last
801 : : * bits are zeros
802 : : */
803 : : static inline
804 : : unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
805 : : {
806 : : unsigned long expires_limit, mask;
807 : : int bit;
808 : :
809 [ + + ]: 831090 : if (timer->slack >= 0) {
810 : 15945 : expires_limit = expires + timer->slack;
811 : : } else {
812 : 815145 : long delta = expires - jiffies;
813 : :
814 [ + + ]: 815145 : if (delta < 256)
815 : : return expires;
816 : :
817 : 39661 : expires_limit = expires + delta / 256;
818 : : }
819 : 55606 : mask = expires ^ expires_limit;
820 [ + ]: 55606 : if (mask == 0)
821 : : return expires;
822 : :
823 : 55607 : bit = find_last_bit(&mask, BITS_PER_LONG);
824 : :
825 : 55607 : mask = (1 << bit) - 1;
826 : :
827 : 55607 : expires_limit = expires_limit & ~(mask);
828 : :
829 : : return expires_limit;
830 : : }
831 : :
832 : : /**
833 : : * mod_timer - modify a timer's timeout
834 : : * @timer: the timer to be modified
835 : : * @expires: new timeout in jiffies
836 : : *
837 : : * mod_timer() is a more efficient way to update the expire field of an
838 : : * active timer (if the timer is inactive it will be activated)
839 : : *
840 : : * mod_timer(timer, expires) is equivalent to:
841 : : *
842 : : * del_timer(timer); timer->expires = expires; add_timer(timer);
843 : : *
844 : : * Note that if there are multiple unserialized concurrent users of the
845 : : * same timer, then mod_timer() is the only safe way to modify the timeout,
846 : : * since add_timer() cannot modify an already running timer.
847 : : *
848 : : * The function returns whether it has modified a pending timer or not.
849 : : * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an
850 : : * active timer returns 1.)
851 : : */
852 : 0 : int mod_timer(struct timer_list *timer, unsigned long expires)
853 : : {
854 : : expires = apply_slack(timer, expires);
855 : :
856 : : /*
857 : : * This is a common optimization triggered by the
858 : : * networking code - if the timer is re-modified
859 : : * to be the same thing then just return:
860 : : */
861 [ + + ][ + + ]: 831090 : if (timer_pending(timer) && timer->expires == expires)
862 : : return 1;
863 : :
864 : 705015 : return __mod_timer(timer, expires, false, TIMER_NOT_PINNED);
865 : : }
866 : : EXPORT_SYMBOL(mod_timer);
867 : :
868 : : /**
869 : : * mod_timer_pinned - modify a timer's timeout
870 : : * @timer: the timer to be modified
871 : : * @expires: new timeout in jiffies
872 : : *
873 : : * mod_timer_pinned() is a way to update the expire field of an
874 : : * active timer (if the timer is inactive it will be activated)
875 : : * and to ensure that the timer is scheduled on the current CPU.
876 : : *
877 : : * Note that this does not prevent the timer from being migrated
878 : : * when the current CPU goes offline. If this is a problem for
879 : : * you, use CPU-hotplug notifiers to handle it correctly, for
880 : : * example, cancelling the timer when the corresponding CPU goes
881 : : * offline.
882 : : *
883 : : * mod_timer_pinned(timer, expires) is equivalent to:
884 : : *
885 : : * del_timer(timer); timer->expires = expires; add_timer(timer);
886 : : */
887 : 0 : int mod_timer_pinned(struct timer_list *timer, unsigned long expires)
888 : : {
889 [ # # ][ # # ]: 0 : if (timer->expires == expires && timer_pending(timer))
890 : : return 1;
891 : :
892 : 0 : return __mod_timer(timer, expires, false, TIMER_PINNED);
893 : : }
894 : : EXPORT_SYMBOL(mod_timer_pinned);
895 : :
896 : : /**
897 : : * add_timer - start a timer
898 : : * @timer: the timer to be added
899 : : *
900 : : * The kernel will do a ->function(->data) callback from the
901 : : * timer interrupt at the ->expires point in the future. The
902 : : * current time is 'jiffies'.
903 : : *
904 : : * The timer's ->expires, ->function (and if the handler uses it, ->data)
905 : : * fields must be set prior calling this function.
906 : : *
907 : : * Timers with an ->expires field in the past will be executed in the next
908 : : * timer tick.
909 : : */
910 : 0 : void add_timer(struct timer_list *timer)
911 : : {
912 [ - + ]: 411595 : BUG_ON(timer_pending(timer));
913 : 411595 : mod_timer(timer, timer->expires);
914 : 411604 : }
915 : : EXPORT_SYMBOL(add_timer);
916 : :
917 : : /**
918 : : * add_timer_on - start a timer on a particular CPU
919 : : * @timer: the timer to be added
920 : : * @cpu: the CPU to start it on
921 : : *
922 : : * This is not very scalable on SMP. Double adds are not possible.
923 : : */
924 : 0 : void add_timer_on(struct timer_list *timer, int cpu)
925 : : {
926 : 100173 : struct tvec_base *base = per_cpu(tvec_bases, cpu);
927 : : unsigned long flags;
928 : :
929 : : timer_stats_timer_set_start_info(timer);
930 [ + - ][ - + ]: 100173 : BUG_ON(timer_pending(timer) || !timer->function);
931 : 100173 : spin_lock_irqsave(&base->lock, flags);
932 : : timer_set_base(timer, base);
933 : 100173 : debug_activate(timer, timer->expires);
934 : 100173 : internal_add_timer(base, timer);
935 : : /*
936 : : * Check whether the other CPU is in dynticks mode and needs
937 : : * to be triggered to reevaluate the timer wheel.
938 : : * We are protected against the other CPU fiddling
939 : : * with the timer by holding the timer base lock. This also
940 : : * makes sure that a CPU on the way to stop its tick can not
941 : : * evaluate the timer wheel.
942 : : */
943 : 100173 : wake_up_nohz_cpu(cpu);
944 : : spin_unlock_irqrestore(&base->lock, flags);
945 : 100173 : }
946 : : EXPORT_SYMBOL_GPL(add_timer_on);
947 : :
948 : : /**
949 : : * del_timer - deactive a timer.
950 : : * @timer: the timer to be deactivated
951 : : *
952 : : * del_timer() deactivates a timer - this works on both active and inactive
953 : : * timers.
954 : : *
955 : : * The function returns whether it has deactivated a pending timer or not.
956 : : * (ie. del_timer() of an inactive timer returns 0, del_timer() of an
957 : : * active timer returns 1.)
958 : : */
959 : 0 : int del_timer(struct timer_list *timer)
960 : : {
961 : : struct tvec_base *base;
962 : : unsigned long flags;
963 : : int ret = 0;
964 : :
965 : : debug_assert_init(timer);
966 : :
967 : : timer_stats_timer_clear_start_info(timer);
968 [ + + ]: 805121 : if (timer_pending(timer)) {
969 : 105822 : base = lock_timer_base(timer, &flags);
970 : 105822 : ret = detach_if_pending(timer, base, true);
971 : 105822 : spin_unlock_irqrestore(&base->lock, flags);
972 : : }
973 : :
974 : 0 : return ret;
975 : : }
976 : : EXPORT_SYMBOL(del_timer);
977 : :
978 : : /**
979 : : * try_to_del_timer_sync - Try to deactivate a timer
980 : : * @timer: timer do del
981 : : *
982 : : * This function tries to deactivate a timer. Upon successful (ret >= 0)
983 : : * exit the timer is not queued and the handler is not running on any CPU.
984 : : */
985 : 0 : int try_to_del_timer_sync(struct timer_list *timer)
986 : : {
987 : : struct tvec_base *base;
988 : : unsigned long flags;
989 : : int ret = -1;
990 : :
991 : : debug_assert_init(timer);
992 : :
993 : 499845 : base = lock_timer_base(timer, &flags);
994 : :
995 [ + + ]: 499851 : if (base->running_timer != timer) {
996 : : timer_stats_timer_clear_start_info(timer);
997 : 497128 : ret = detach_if_pending(timer, base, true);
998 : : }
999 : 2 : spin_unlock_irqrestore(&base->lock, flags);
1000 : :
1001 : 499854 : return ret;
1002 : : }
1003 : : EXPORT_SYMBOL(try_to_del_timer_sync);
1004 : :
1005 : : #ifdef CONFIG_SMP
1006 : : /**
1007 : : * del_timer_sync - deactivate a timer and wait for the handler to finish.
1008 : : * @timer: the timer to be deactivated
1009 : : *
1010 : : * This function only differs from del_timer() on SMP: besides deactivating
1011 : : * the timer it also makes sure the handler has finished executing on other
1012 : : * CPUs.
1013 : : *
1014 : : * Synchronization rules: Callers must prevent restarting of the timer,
1015 : : * otherwise this function is meaningless. It must not be called from
1016 : : * interrupt contexts unless the timer is an irqsafe one. The caller must
1017 : : * not hold locks which would prevent completion of the timer's
1018 : : * handler. The timer's handler must not call add_timer_on(). Upon exit the
1019 : : * timer is not queued and the handler is not running on any CPU.
1020 : : *
1021 : : * Note: For !irqsafe timers, you must not hold locks that are held in
1022 : : * interrupt context while calling this function. Even if the lock has
1023 : : * nothing to do with the timer in question. Here's why:
1024 : : *
1025 : : * CPU0 CPU1
1026 : : * ---- ----
1027 : : * <SOFTIRQ>
1028 : : * call_timer_fn();
1029 : : * base->running_timer = mytimer;
1030 : : * spin_lock_irq(somelock);
1031 : : * <IRQ>
1032 : : * spin_lock(somelock);
1033 : : * del_timer_sync(mytimer);
1034 : : * while (base->running_timer == mytimer);
1035 : : *
1036 : : * Now del_timer_sync() will never return and never release somelock.
1037 : : * The interrupt on the other CPU is waiting to grab somelock but
1038 : : * it has interrupted the softirq that CPU0 is waiting to finish.
1039 : : *
1040 : : * The function returns whether it has deactivated a pending timer or not.
1041 : : */
1042 : 0 : int del_timer_sync(struct timer_list *timer)
1043 : : {
1044 : : #ifdef CONFIG_LOCKDEP
1045 : : unsigned long flags;
1046 : :
1047 : : /*
1048 : : * If lockdep gives a backtrace here, please reference
1049 : : * the synchronization rules above.
1050 : : */
1051 : : local_irq_save(flags);
1052 : : lock_map_acquire(&timer->lockdep_map);
1053 : : lock_map_release(&timer->lockdep_map);
1054 : : local_irq_restore(flags);
1055 : : #endif
1056 : : /*
1057 : : * don't use it in hardirq context, because it
1058 : : * could lead to deadlock.
1059 : : */
1060 [ - + ][ # # ]: 497130 : WARN_ON(in_irq() && !tbase_get_irqsafe(timer->base));
[ # # ]
1061 : : for (;;) {
1062 : 499853 : int ret = try_to_del_timer_sync(timer);
1063 [ + + ]: 499854 : if (ret >= 0)
1064 : 497130 : return ret;
1065 : 2724 : cpu_relax();
1066 : 2724 : }
1067 : : }
1068 : : EXPORT_SYMBOL(del_timer_sync);
1069 : : #endif
1070 : :
1071 : 0 : static int cascade(struct tvec_base *base, struct tvec *tv, int index)
1072 : : {
1073 : : /* cascade all the timers from tv up one level */
1074 : : struct timer_list *timer, *tmp;
1075 : : struct list_head tv_list;
1076 : :
1077 : 64652 : list_replace_init(tv->vec + index, &tv_list);
1078 : :
1079 : : /*
1080 : : * We are removing _all_ timers from the list, so we
1081 : : * don't have to detach them individually.
1082 : : */
1083 [ + + ]: 84241 : list_for_each_entry_safe(timer, tmp, &tv_list, entry) {
1084 [ + ]: 19595 : BUG_ON(tbase_get_base(timer->base) != base);
1085 : : /* No accounting, while moving them */
1086 : 19599 : __internal_add_timer(base, timer);
1087 : : }
1088 : :
1089 : 64646 : return index;
1090 : : }
1091 : :
1092 : 0 : static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long),
1093 : : unsigned long data)
1094 : : {
1095 : : int count = preempt_count();
1096 : :
1097 : : #ifdef CONFIG_LOCKDEP
1098 : : /*
1099 : : * It is permissible to free the timer from inside the
1100 : : * function that is called from it, this we need to take into
1101 : : * account for lockdep too. To avoid bogus "held lock freed"
1102 : : * warnings as well as problems when looking into
1103 : : * timer->lockdep_map, make a copy and use that here.
1104 : : */
1105 : : struct lockdep_map lockdep_map;
1106 : :
1107 : : lockdep_copy_map(&lockdep_map, &timer->lockdep_map);
1108 : : #endif
1109 : : /*
1110 : : * Couple the lock chain with the lock chain at
1111 : : * del_timer_sync() by acquiring the lock_map around the fn()
1112 : : * call here and in del_timer_sync().
1113 : : */
1114 : : lock_map_acquire(&lockdep_map);
1115 : :
1116 : : trace_timer_expire_entry(timer);
1117 : 1105392 : fn(data);
1118 : : trace_timer_expire_exit(timer);
1119 : :
1120 : : lock_map_release(&lockdep_map);
1121 : :
1122 [ - + ]: 1105753 : if (count != preempt_count()) {
1123 [ # # ][ # # ]: 0 : WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n",
1124 : : fn, count, preempt_count());
1125 : : /*
1126 : : * Restore the preempt count. That gives us a decent
1127 : : * chance to survive and extract information. If the
1128 : : * callback kept a lock held, bad luck, but not worse
1129 : : * than the BUG() we had.
1130 : : */
1131 : : preempt_count_set(count);
1132 : : }
1133 : 1105753 : }
1134 : :
1135 : : #define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK)
1136 : :
1137 : : /**
1138 : : * __run_timers - run all expired timers (if any) on this CPU.
1139 : : * @base: the timer vector to be processed.
1140 : : *
1141 : : * This function cascades all vectors and executes all expired timer
1142 : : * vectors.
1143 : : */
1144 : : static inline void __run_timers(struct tvec_base *base)
1145 : : {
1146 : : struct timer_list *timer;
1147 : :
1148 : : spin_lock_irq(&base->lock);
1149 [ + + ]: 18790045 : while (time_after_eq(jiffies, base->timer_jiffies)) {
1150 : : struct list_head work_list;
1151 : : struct list_head *head = &work_list;
1152 : 16217008 : int index = base->timer_jiffies & TVR_MASK;
1153 : :
1154 : : /*
1155 : : * Cascade timers:
1156 : : */
1157 [ + + + + ]: 16280498 : if (!index &&
1158 [ + + ]: 64559 : (!cascade(base, &base->tv2, INDEX(0))) &&
1159 [ + + ]: 1012 : (!cascade(base, &base->tv3, INDEX(1))) &&
1160 : 20 : !cascade(base, &base->tv4, INDEX(2)))
1161 : 4 : cascade(base, &base->tv5, INDEX(3));
1162 : 16225518 : ++base->timer_jiffies;
1163 : 16225518 : list_replace_init(base->tv1.vec + index, &work_list);
1164 [ + + ]: 17331596 : while (!list_empty(head)) {
1165 : : void (*fn)(unsigned long);
1166 : : unsigned long data;
1167 : : bool irqsafe;
1168 : :
1169 : : timer = list_first_entry(head, struct timer_list,entry);
1170 : 1105127 : fn = timer->function;
1171 : 1105127 : data = timer->data;
1172 : 1105127 : irqsafe = tbase_get_irqsafe(timer->base);
1173 : :
1174 : 1105127 : timer_stats_account_timer(timer);
1175 : :
1176 : 1105798 : base->running_timer = timer;
1177 : : detach_expired_timer(timer, base);
1178 : :
1179 [ + + ]: 1105755 : if (irqsafe) {
1180 : : spin_unlock(&base->lock);
1181 : 260982 : call_timer_fn(timer, fn, data);
1182 : : spin_lock(&base->lock);
1183 : : } else {
1184 : : spin_unlock_irq(&base->lock);
1185 : 845228 : call_timer_fn(timer, fn, data);
1186 : : spin_lock_irq(&base->lock);
1187 : : }
1188 : : }
1189 : : }
1190 : 2573037 : base->running_timer = NULL;
1191 : : spin_unlock_irq(&base->lock);
1192 : : }
1193 : :
1194 : : #ifdef CONFIG_NO_HZ_COMMON
1195 : : /*
1196 : : * Find out when the next timer event is due to happen. This
1197 : : * is used on S/390 to stop all activity when a CPU is idle.
1198 : : * This function needs to be called with interrupts disabled.
1199 : : */
1200 : 0 : static unsigned long __next_timer_interrupt(struct tvec_base *base)
1201 : : {
1202 : 958791 : unsigned long timer_jiffies = base->timer_jiffies;
1203 : 958791 : unsigned long expires = timer_jiffies + NEXT_TIMER_MAX_DELTA;
1204 : : int index, slot, array, found = 0;
1205 : : struct timer_list *nte;
1206 : : struct tvec *varray[4];
1207 : :
1208 : : /* Look for timer events in tv1. */
1209 : 958791 : index = slot = timer_jiffies & TVR_MASK;
1210 : : do {
1211 [ + + ]: 19013772 : list_for_each_entry(nte, base->tv1.vec + slot, entry) {
1212 [ + + ]: 1184304 : if (tbase_get_deferrable(nte->base))
1213 : 256941 : continue;
1214 : :
1215 : : found = 1;
1216 : 927363 : expires = nte->expires;
1217 : : /* Look at the cascade bucket(s)? */
1218 [ + + ]: 927363 : if (!index || slot < index)
1219 : : goto cascade;
1220 : : return expires;
1221 : : }
1222 : 17829468 : slot = (slot + 1) & TVR_MASK;
1223 [ + + ]: 17829468 : } while (slot != index);
1224 : :
1225 : : cascade:
1226 : : /* Calculate the next cascade event */
1227 [ + + ]: 72924 : if (index)
1228 : 68778 : timer_jiffies += TVR_SIZE - index;
1229 : 72924 : timer_jiffies >>= TVR_BITS;
1230 : :
1231 : : /* Check tv2-tv5. */
1232 : 72924 : varray[0] = &base->tv2;
1233 : 72924 : varray[1] = &base->tv3;
1234 : 72924 : varray[2] = &base->tv4;
1235 : 72924 : varray[3] = &base->tv5;
1236 : :
1237 [ + + ]: 75830 : for (array = 0; array < 4; array++) {
1238 : 75829 : struct tvec *varp = varray[array];
1239 : :
1240 : 75829 : index = slot = timer_jiffies & TVN_MASK;
1241 : : do {
1242 [ + + ]: 207325 : list_for_each_entry(nte, varp->vec + slot, entry) {
1243 [ + + ]: 57734 : if (tbase_get_deferrable(nte->base))
1244 : 17281 : continue;
1245 : :
1246 : : found = 1;
1247 [ + + ]: 40453 : if (time_before(nte->expires, expires))
1248 : : expires = nte->expires;
1249 : : }
1250 : : /*
1251 : : * Do we still search for the first timer or are
1252 : : * we looking up the cascade buckets ?
1253 : : */
1254 [ + ]: 149591 : if (found) {
1255 : : /* Look at the cascade bucket(s)? */
1256 [ + ]: 0 : if (!index || slot < index)
1257 : : break;
1258 : : return expires;
1259 : : }
1260 : 73765 : slot = (slot + 1) & TVN_MASK;
1261 [ + + ]: 73765 : } while (slot != index);
1262 : :
1263 [ + + ]: 2906 : if (index)
1264 : 1433 : timer_jiffies += TVN_SIZE - index;
1265 : 2906 : timer_jiffies >>= TVN_BITS;
1266 : : }
1267 : : return expires;
1268 : : }
1269 : :
1270 : : /*
1271 : : * Check, if the next hrtimer event is before the next timer wheel
1272 : : * event:
1273 : : */
1274 : 0 : static unsigned long cmp_next_hrtimer_event(unsigned long now,
1275 : : unsigned long expires)
1276 : : {
1277 : 4949173 : ktime_t hr_delta = hrtimer_get_next_event();
1278 : : struct timespec tsdelta;
1279 : : unsigned long delta;
1280 : :
1281 [ - + ]: 4945490 : if (hr_delta.tv64 == KTIME_MAX)
1282 : : return expires;
1283 : :
1284 : : /*
1285 : : * Expired timer available, let it expire in the next tick
1286 : : */
1287 [ # # ]: 0 : if (hr_delta.tv64 <= 0)
1288 : 0 : return now + 1;
1289 : :
1290 : 0 : tsdelta = ktime_to_timespec(hr_delta);
1291 : 0 : delta = timespec_to_jiffies(&tsdelta);
1292 : :
1293 : : /*
1294 : : * Limit the delta to the max value, which is checked in
1295 : : * tick_nohz_stop_sched_tick():
1296 : : */
1297 [ # # ]: 0 : if (delta > NEXT_TIMER_MAX_DELTA)
1298 : : delta = NEXT_TIMER_MAX_DELTA;
1299 : :
1300 : : /*
1301 : : * Take rounding errors in to account and make sure, that it
1302 : : * expires in the next tick. Otherwise we go into an endless
1303 : : * ping pong due to tick_nohz_stop_sched_tick() retriggering
1304 : : * the timer softirq
1305 : : */
1306 [ # # ]: 0 : if (delta < 1)
1307 : : delta = 1;
1308 : 0 : now += delta;
1309 [ - ]: 0 : if (time_before(now, expires))
1310 : : return now;
1311 : 0 : return expires;
1312 : : }
1313 : :
1314 : : /**
1315 : : * get_next_timer_interrupt - return the jiffy of the next pending timer
1316 : : * @now: current time (in jiffies)
1317 : : */
1318 : 0 : unsigned long get_next_timer_interrupt(unsigned long now)
1319 : : {
1320 : 9860692 : struct tvec_base *base = __this_cpu_read(tvec_bases);
1321 : 4930346 : unsigned long expires = now + NEXT_TIMER_MAX_DELTA;
1322 : :
1323 : : /*
1324 : : * Pretend that there is no timer pending if the cpu is offline.
1325 : : * Possible pending timers will be migrated later to an active cpu.
1326 : : */
1327 [ + ]: 4930346 : if (cpu_is_offline(smp_processor_id()))
1328 : : return expires;
1329 : :
1330 : : spin_lock(&base->lock);
1331 [ + + ]: 4950298 : if (base->active_timers) {
1332 [ + + ]: 3244053 : if (time_before_eq(base->next_timer, base->timer_jiffies))
1333 : 958802 : base->next_timer = __next_timer_interrupt(base);
1334 : 3244114 : expires = base->next_timer;
1335 : : }
1336 : : spin_unlock(&base->lock);
1337 : :
1338 [ + + ]: 4950381 : if (time_before_eq(expires, now))
1339 : : return now;
1340 : :
1341 : 4928310 : return cmp_next_hrtimer_event(now, expires);
1342 : : }
1343 : : #endif
1344 : :
1345 : : /*
1346 : : * Called from the timer interrupt handler to charge one tick to the current
1347 : : * process. user_tick is 1 if the tick is user time, 0 for system.
1348 : : */
1349 : 0 : void update_process_times(int user_tick)
1350 : : {
1351 : 2568923 : struct task_struct *p = current;
1352 : 2568923 : int cpu = smp_processor_id();
1353 : :
1354 : : /* Note: this timer irq context must be accounted for as well. */
1355 : 2568923 : account_process_tick(p, user_tick);
1356 : : run_local_timers();
1357 : 2507542 : rcu_check_callbacks(cpu, user_tick);
1358 : : #ifdef CONFIG_IRQ_WORK
1359 [ + + ]: 2600017 : if (in_irq())
1360 : 2591282 : irq_work_run();
1361 : : #endif
1362 : 2551372 : scheduler_tick();
1363 : 2592938 : run_posix_cpu_timers(p);
1364 : 2565475 : }
1365 : :
1366 : : /*
1367 : : * This function runs timers and the timer-tq in bottom half context.
1368 : : */
1369 : 0 : static void run_timer_softirq(struct softirq_action *h)
1370 : : {
1371 : 5078198 : struct tvec_base *base = __this_cpu_read(tvec_bases);
1372 : :
1373 : 2539099 : hrtimer_run_pending();
1374 : :
1375 [ + + ]: 2560898 : if (time_after_eq(jiffies, base->timer_jiffies))
1376 : : __run_timers(base);
1377 : 2618055 : }
1378 : :
1379 : : /*
1380 : : * Called by the local, per-CPU timer interrupt on SMP.
1381 : : */
1382 : 0 : void run_local_timers(void)
1383 : : {
1384 : 2557103 : hrtimer_run_queues();
1385 : 2491276 : raise_softirq(TIMER_SOFTIRQ);
1386 : 0 : }
1387 : :
1388 : : #ifdef __ARCH_WANT_SYS_ALARM
1389 : :
1390 : : /*
1391 : : * For backwards compatibility? This can be done in libc so Alpha
1392 : : * and all newer ports shouldn't need it.
1393 : : */
1394 : : SYSCALL_DEFINE1(alarm, unsigned int, seconds)
1395 : : {
1396 : : return alarm_setitimer(seconds);
1397 : : }
1398 : :
1399 : : #endif
1400 : :
1401 : 0 : static void process_timeout(unsigned long __data)
1402 : : {
1403 : 461251 : wake_up_process((struct task_struct *)__data);
1404 : 461248 : }
1405 : :
1406 : : /**
1407 : : * schedule_timeout - sleep until timeout
1408 : : * @timeout: timeout value in jiffies
1409 : : *
1410 : : * Make the current task sleep until @timeout jiffies have
1411 : : * elapsed. The routine will return immediately unless
1412 : : * the current task state has been set (see set_current_state()).
1413 : : *
1414 : : * You can set the task state as follows -
1415 : : *
1416 : : * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to
1417 : : * pass before the routine returns. The routine will return 0
1418 : : *
1419 : : * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1420 : : * delivered to the current task. In this case the remaining time
1421 : : * in jiffies will be returned, or 0 if the timer expired in time
1422 : : *
1423 : : * The current task state is guaranteed to be TASK_RUNNING when this
1424 : : * routine returns.
1425 : : *
1426 : : * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule
1427 : : * the CPU away without a bound on the timeout. In this case the return
1428 : : * value will be %MAX_SCHEDULE_TIMEOUT.
1429 : : *
1430 : : * In all cases the return value is guaranteed to be non-negative.
1431 : : */
1432 : 0 : signed long __sched schedule_timeout(signed long timeout)
1433 : : {
1434 : : struct timer_list timer;
1435 : : unsigned long expire;
1436 : :
1437 [ + + ]: 2127639 : switch (timeout)
1438 : : {
1439 : : case MAX_SCHEDULE_TIMEOUT:
1440 : : /*
1441 : : * These two special cases are useful to be comfortable
1442 : : * in the caller. Nothing more. We could take
1443 : : * MAX_SCHEDULE_TIMEOUT from one of the negative value
1444 : : * but I' d like to return a valid offset (>=0) to allow
1445 : : * the caller to do everything it want with the retval.
1446 : : */
1447 : 1649649 : schedule();
1448 : 1649675 : goto out;
1449 : : default:
1450 : : /*
1451 : : * Another bit of PARANOID. Note that the retval will be
1452 : : * 0 since no piece of kernel is supposed to do a check
1453 : : * for a negative retval of schedule_timeout() (since it
1454 : : * should never happens anyway). You just have the printk()
1455 : : * that will tell you if something is gone wrong and where.
1456 : : */
1457 [ - + ]: 477990 : if (timeout < 0) {
1458 : 0 : printk(KERN_ERR "schedule_timeout: wrong timeout "
1459 : : "value %lx\n", timeout);
1460 : 0 : dump_stack();
1461 : 0 : current->state = TASK_RUNNING;
1462 : 0 : goto out;
1463 : : }
1464 : : }
1465 : :
1466 : 477990 : expire = timeout + jiffies;
1467 : :
1468 : 955978 : setup_timer_on_stack(&timer, process_timeout, (unsigned long)current);
1469 : : __mod_timer(&timer, expire, false, TIMER_NOT_PINNED);
1470 : 477991 : schedule();
1471 : 477987 : del_singleshot_timer_sync(&timer);
1472 : :
1473 : : /* Remove the timer from the object tracker */
1474 : : destroy_timer_on_stack(&timer);
1475 : :
1476 : 477991 : timeout = expire - jiffies;
1477 : :
1478 : : out:
1479 : 2127666 : return timeout < 0 ? 0 : timeout;
1480 : : }
1481 : : EXPORT_SYMBOL(schedule_timeout);
1482 : :
1483 : : /*
1484 : : * We can use __set_current_state() here because schedule_timeout() calls
1485 : : * schedule() unconditionally.
1486 : : */
1487 : 0 : signed long __sched schedule_timeout_interruptible(signed long timeout)
1488 : : {
1489 : 15 : __set_current_state(TASK_INTERRUPTIBLE);
1490 : 15 : return schedule_timeout(timeout);
1491 : : }
1492 : : EXPORT_SYMBOL(schedule_timeout_interruptible);
1493 : :
1494 : 0 : signed long __sched schedule_timeout_killable(signed long timeout)
1495 : : {
1496 : 3 : __set_current_state(TASK_KILLABLE);
1497 : 3 : return schedule_timeout(timeout);
1498 : : }
1499 : : EXPORT_SYMBOL(schedule_timeout_killable);
1500 : :
1501 : 0 : signed long __sched schedule_timeout_uninterruptible(signed long timeout)
1502 : : {
1503 : 350 : __set_current_state(TASK_UNINTERRUPTIBLE);
1504 : 350 : return schedule_timeout(timeout);
1505 : : }
1506 : : EXPORT_SYMBOL(schedule_timeout_uninterruptible);
1507 : :
1508 : 0 : static int init_timers_cpu(int cpu)
1509 : : {
1510 : : int j;
1511 : : struct tvec_base *base;
1512 : : static char tvec_base_done[NR_CPUS];
1513 : :
1514 [ - + ]: 81 : if (!tvec_base_done[cpu]) {
1515 : : static char boot_done;
1516 : :
1517 [ # # ]: 0 : if (boot_done) {
1518 : : /*
1519 : : * The APs use this path later in boot
1520 : : */
1521 : : base = kzalloc_node(sizeof(*base), GFP_KERNEL,
1522 : : cpu_to_node(cpu));
1523 [ # # ]: 0 : if (!base)
1524 : : return -ENOMEM;
1525 : :
1526 : : /* Make sure that tvec_base is 2 byte aligned */
1527 [ - + ]: 81 : if (tbase_get_deferrable(base)) {
1528 : 0 : WARN_ON(1);
1529 : 0 : kfree(base);
1530 : 0 : return -ENOMEM;
1531 : : }
1532 : 81 : per_cpu(tvec_bases, cpu) = base;
1533 : : } else {
1534 : : /*
1535 : : * This is for the boot CPU - we use compile-time
1536 : : * static initialisation because per-cpu memory isn't
1537 : : * ready yet and because the memory allocators are not
1538 : : * initialised either.
1539 : : */
1540 : 0 : boot_done = 1;
1541 : : base = &boot_tvec_bases;
1542 : : }
1543 : 81 : spin_lock_init(&base->lock);
1544 : 81 : tvec_base_done[cpu] = 1;
1545 : : } else {
1546 : 81 : base = per_cpu(tvec_bases, cpu);
1547 : : }
1548 : :
1549 : :
1550 [ + + ]: 5346 : for (j = 0; j < TVN_SIZE; j++) {
1551 : 5184 : INIT_LIST_HEAD(base->tv5.vec + j);
1552 : 5184 : INIT_LIST_HEAD(base->tv4.vec + j);
1553 : 5184 : INIT_LIST_HEAD(base->tv3.vec + j);
1554 : 5184 : INIT_LIST_HEAD(base->tv2.vec + j);
1555 : : }
1556 [ + + ]: 20817 : for (j = 0; j < TVR_SIZE; j++)
1557 : 20736 : INIT_LIST_HEAD(base->tv1.vec + j);
1558 : :
1559 : 81 : base->timer_jiffies = jiffies;
1560 : 81 : base->next_timer = base->timer_jiffies;
1561 : 81 : base->active_timers = 0;
1562 : 81 : return 0;
1563 : : }
1564 : :
1565 : : #ifdef CONFIG_HOTPLUG_CPU
1566 : 0 : static void migrate_timer_list(struct tvec_base *new_base, struct list_head *head)
1567 : : {
1568 : : struct timer_list *timer;
1569 : :
1570 [ + + ]: 39999 : while (!list_empty(head)) {
1571 : : timer = list_first_entry(head, struct timer_list, entry);
1572 : : /* We ignore the accounting on the dying cpu */
1573 : : detach_timer(timer, false);
1574 : : timer_set_base(timer, new_base);
1575 : 63 : internal_add_timer(new_base, timer);
1576 : : }
1577 : 39936 : }
1578 : :
1579 : 0 : static void migrate_timers(int cpu)
1580 : : {
1581 : : struct tvec_base *old_base;
1582 : : struct tvec_base *new_base;
1583 : : int i;
1584 : :
1585 [ - + ]: 78 : BUG_ON(cpu_online(cpu));
1586 : 78 : old_base = per_cpu(tvec_bases, cpu);
1587 : 78 : new_base = get_cpu_var(tvec_bases);
1588 : : /*
1589 : : * The caller is globally serialized and nobody else
1590 : : * takes two locks at once, deadlock is not possible.
1591 : : */
1592 : : spin_lock_irq(&new_base->lock);
1593 : 78 : spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1594 : :
1595 [ + - ]: 156 : BUG_ON(old_base->running_timer);
1596 : :
1597 [ + + ]: 20046 : for (i = 0; i < TVR_SIZE; i++)
1598 : 19968 : migrate_timer_list(new_base, old_base->tv1.vec + i);
1599 [ + + ]: 5070 : for (i = 0; i < TVN_SIZE; i++) {
1600 : 4992 : migrate_timer_list(new_base, old_base->tv2.vec + i);
1601 : 4992 : migrate_timer_list(new_base, old_base->tv3.vec + i);
1602 : 4992 : migrate_timer_list(new_base, old_base->tv4.vec + i);
1603 : 4992 : migrate_timer_list(new_base, old_base->tv5.vec + i);
1604 : : }
1605 : :
1606 : : spin_unlock(&old_base->lock);
1607 : : spin_unlock_irq(&new_base->lock);
1608 : 78 : put_cpu_var(tvec_bases);
1609 : 78 : }
1610 : : #endif /* CONFIG_HOTPLUG_CPU */
1611 : :
1612 : 0 : static int timer_cpu_notify(struct notifier_block *self,
1613 : : unsigned long action, void *hcpu)
1614 : : {
1615 : 555 : long cpu = (long)hcpu;
1616 : : int err;
1617 : :
1618 [ + + + ]: 555 : switch(action) {
1619 : : case CPU_UP_PREPARE:
1620 : : case CPU_UP_PREPARE_FROZEN:
1621 : 81 : err = init_timers_cpu(cpu);
1622 [ - + ]: 81 : if (err < 0)
1623 : 0 : return notifier_from_errno(err);
1624 : : break;
1625 : : #ifdef CONFIG_HOTPLUG_CPU
1626 : : case CPU_DEAD:
1627 : : case CPU_DEAD_FROZEN:
1628 : 78 : migrate_timers(cpu);
1629 : 78 : break;
1630 : : #endif
1631 : : default:
1632 : : break;
1633 : : }
1634 : : return NOTIFY_OK;
1635 : : }
1636 : :
1637 : : static struct notifier_block timers_nb = {
1638 : : .notifier_call = timer_cpu_notify,
1639 : : };
1640 : :
1641 : :
1642 : 0 : void __init init_timers(void)
1643 : : {
1644 : : int err;
1645 : :
1646 : : /* ensure there are enough low bits for flags in timer->base pointer */
1647 : : BUILD_BUG_ON(__alignof__(struct tvec_base) & TIMER_FLAG_MASK);
1648 : :
1649 : 0 : err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
1650 : 0 : (void *)(long)smp_processor_id());
1651 : 0 : init_timer_stats();
1652 : :
1653 [ # # ]: 0 : BUG_ON(err != NOTIFY_OK);
1654 : 0 : register_cpu_notifier(&timers_nb);
1655 : 0 : open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
1656 : 0 : }
1657 : :
1658 : : /**
1659 : : * msleep - sleep safely even with waitqueue interruptions
1660 : : * @msecs: Time in milliseconds to sleep for
1661 : : */
1662 : 0 : void msleep(unsigned int msecs)
1663 : : {
1664 : 18 : unsigned long timeout = msecs_to_jiffies(msecs) + 1;
1665 : :
1666 [ + + ]: 54 : while (timeout)
1667 : 18 : timeout = schedule_timeout_uninterruptible(timeout);
1668 : 18 : }
1669 : :
1670 : : EXPORT_SYMBOL(msleep);
1671 : :
1672 : : /**
1673 : : * msleep_interruptible - sleep waiting for signals
1674 : : * @msecs: Time in milliseconds to sleep for
1675 : : */
1676 : 0 : unsigned long msleep_interruptible(unsigned int msecs)
1677 : : {
1678 : 10 : unsigned long timeout = msecs_to_jiffies(msecs) + 1;
1679 : :
1680 [ + + ][ + - ]: 20 : while (timeout && !signal_pending(current))
1681 : 10 : timeout = schedule_timeout_interruptible(timeout);
1682 : 10 : return jiffies_to_msecs(timeout);
1683 : : }
1684 : :
1685 : : EXPORT_SYMBOL(msleep_interruptible);
1686 : :
1687 : 0 : static int __sched do_usleep_range(unsigned long min, unsigned long max)
1688 : : {
1689 : : ktime_t kmin;
1690 : : unsigned long delta;
1691 : :
1692 : 0 : kmin = ktime_set(0, min * NSEC_PER_USEC);
1693 : 0 : delta = (max - min) * NSEC_PER_USEC;
1694 : 0 : return schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL);
1695 : : }
1696 : :
1697 : : /**
1698 : : * usleep_range - Drop in replacement for udelay where wakeup is flexible
1699 : : * @min: Minimum time in usecs to sleep
1700 : : * @max: Maximum time in usecs to sleep
1701 : : */
1702 : 0 : void usleep_range(unsigned long min, unsigned long max)
1703 : : {
1704 : 0 : __set_current_state(TASK_UNINTERRUPTIBLE);
1705 : 0 : do_usleep_range(min, max);
1706 : 0 : }
1707 : : EXPORT_SYMBOL(usleep_range);
|
