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35728b82 | 1 | // SPDX-License-Identifier: GPL-2.0 |
906568c9 | 2 | /* |
906568c9 TG |
3 | * This file contains the base functions to manage periodic tick |
4 | * related events. | |
5 | * | |
6 | * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de> | |
7 | * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar | |
8 | * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner | |
906568c9 TG |
9 | */ |
10 | #include <linux/cpu.h> | |
11 | #include <linux/err.h> | |
12 | #include <linux/hrtimer.h> | |
d7b90689 | 13 | #include <linux/interrupt.h> |
906568c9 TG |
14 | #include <linux/percpu.h> |
15 | #include <linux/profile.h> | |
16 | #include <linux/sched.h> | |
ccf33d68 | 17 | #include <linux/module.h> |
75e0678e | 18 | #include <trace/events/power.h> |
906568c9 | 19 | |
d7b90689 RK |
20 | #include <asm/irq_regs.h> |
21 | ||
f8381cba TG |
22 | #include "tick-internal.h" |
23 | ||
906568c9 TG |
24 | /* |
25 | * Tick devices | |
26 | */ | |
f8381cba | 27 | DEFINE_PER_CPU(struct tick_device, tick_cpu_device); |
906568c9 TG |
28 | /* |
29 | * Tick next event: keeps track of the tick time | |
30 | */ | |
f8381cba TG |
31 | ktime_t tick_next_period; |
32 | ktime_t tick_period; | |
050ded1b AM |
33 | |
34 | /* | |
35 | * tick_do_timer_cpu is a timer core internal variable which holds the CPU NR | |
36 | * which is responsible for calling do_timer(), i.e. the timekeeping stuff. This | |
37 | * variable has two functions: | |
38 | * | |
39 | * 1) Prevent a thundering herd issue of a gazillion of CPUs trying to grab the | |
40 | * timekeeping lock all at once. Only the CPU which is assigned to do the | |
41 | * update is handling it. | |
42 | * | |
43 | * 2) Hand off the duty in the NOHZ idle case by setting the value to | |
44 | * TICK_DO_TIMER_NONE, i.e. a non existing CPU. So the next cpu which looks | |
45 | * at it will take over and keep the time keeping alive. The handover | |
46 | * procedure also covers cpu hotplug. | |
47 | */ | |
6441402b | 48 | int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT; |
08ae95f4 NP |
49 | #ifdef CONFIG_NO_HZ_FULL |
50 | /* | |
51 | * tick_do_timer_boot_cpu indicates the boot CPU temporarily owns | |
52 | * tick_do_timer_cpu and it should be taken over by an eligible secondary | |
53 | * when one comes online. | |
54 | */ | |
55 | static int tick_do_timer_boot_cpu __read_mostly = -1; | |
56 | #endif | |
906568c9 | 57 | |
289f480a IM |
58 | /* |
59 | * Debugging: see timer_list.c | |
60 | */ | |
61 | struct tick_device *tick_get_device(int cpu) | |
62 | { | |
63 | return &per_cpu(tick_cpu_device, cpu); | |
64 | } | |
65 | ||
79bf2bb3 TG |
66 | /** |
67 | * tick_is_oneshot_available - check for a oneshot capable event device | |
68 | */ | |
69 | int tick_is_oneshot_available(void) | |
70 | { | |
909ea964 | 71 | struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev); |
79bf2bb3 | 72 | |
3a142a06 TG |
73 | if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT)) |
74 | return 0; | |
75 | if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) | |
76 | return 1; | |
77 | return tick_broadcast_oneshot_available(); | |
79bf2bb3 TG |
78 | } |
79 | ||
906568c9 TG |
80 | /* |
81 | * Periodic tick | |
82 | */ | |
83 | static void tick_periodic(int cpu) | |
84 | { | |
85 | if (tick_do_timer_cpu == cpu) { | |
d6ad4187 | 86 | write_seqlock(&jiffies_lock); |
906568c9 TG |
87 | |
88 | /* Keep track of the next tick event */ | |
89 | tick_next_period = ktime_add(tick_next_period, tick_period); | |
90 | ||
91 | do_timer(1); | |
d6ad4187 | 92 | write_sequnlock(&jiffies_lock); |
47a1b796 | 93 | update_wall_time(); |
906568c9 TG |
94 | } |
95 | ||
96 | update_process_times(user_mode(get_irq_regs())); | |
97 | profile_tick(CPU_PROFILING); | |
98 | } | |
99 | ||
100 | /* | |
101 | * Event handler for periodic ticks | |
102 | */ | |
103 | void tick_handle_periodic(struct clock_event_device *dev) | |
104 | { | |
105 | int cpu = smp_processor_id(); | |
b97f0291 | 106 | ktime_t next = dev->next_event; |
906568c9 TG |
107 | |
108 | tick_periodic(cpu); | |
109 | ||
c6eb3f70 TG |
110 | #if defined(CONFIG_HIGH_RES_TIMERS) || defined(CONFIG_NO_HZ_COMMON) |
111 | /* | |
112 | * The cpu might have transitioned to HIGHRES or NOHZ mode via | |
113 | * update_process_times() -> run_local_timers() -> | |
114 | * hrtimer_run_queues(). | |
115 | */ | |
116 | if (dev->event_handler != tick_handle_periodic) | |
117 | return; | |
118 | #endif | |
119 | ||
472c4a94 | 120 | if (!clockevent_state_oneshot(dev)) |
906568c9 | 121 | return; |
906568c9 | 122 | for (;;) { |
b97f0291 VK |
123 | /* |
124 | * Setup the next period for devices, which do not have | |
125 | * periodic mode: | |
126 | */ | |
127 | next = ktime_add(next, tick_period); | |
128 | ||
d1748302 | 129 | if (!clockevents_program_event(dev, next, false)) |
906568c9 | 130 | return; |
74a03b69 JS |
131 | /* |
132 | * Have to be careful here. If we're in oneshot mode, | |
133 | * before we call tick_periodic() in a loop, we need | |
134 | * to be sure we're using a real hardware clocksource. | |
135 | * Otherwise we could get trapped in an infinite | |
136 | * loop, as the tick_periodic() increments jiffies, | |
cacb3c76 | 137 | * which then will increment time, possibly causing |
74a03b69 JS |
138 | * the loop to trigger again and again. |
139 | */ | |
140 | if (timekeeping_valid_for_hres()) | |
141 | tick_periodic(cpu); | |
906568c9 TG |
142 | } |
143 | } | |
144 | ||
145 | /* | |
146 | * Setup the device for a periodic tick | |
147 | */ | |
f8381cba | 148 | void tick_setup_periodic(struct clock_event_device *dev, int broadcast) |
906568c9 | 149 | { |
f8381cba TG |
150 | tick_set_periodic_handler(dev, broadcast); |
151 | ||
152 | /* Broadcast setup ? */ | |
153 | if (!tick_device_is_functional(dev)) | |
154 | return; | |
906568c9 | 155 | |
27ce4cb4 TG |
156 | if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) && |
157 | !tick_broadcast_oneshot_active()) { | |
d7eb231c | 158 | clockevents_switch_state(dev, CLOCK_EVT_STATE_PERIODIC); |
906568c9 | 159 | } else { |
e1e41b6c | 160 | unsigned int seq; |
906568c9 TG |
161 | ktime_t next; |
162 | ||
163 | do { | |
d6ad4187 | 164 | seq = read_seqbegin(&jiffies_lock); |
906568c9 | 165 | next = tick_next_period; |
d6ad4187 | 166 | } while (read_seqretry(&jiffies_lock, seq)); |
906568c9 | 167 | |
d7eb231c | 168 | clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT); |
906568c9 TG |
169 | |
170 | for (;;) { | |
d1748302 | 171 | if (!clockevents_program_event(dev, next, false)) |
906568c9 TG |
172 | return; |
173 | next = ktime_add(next, tick_period); | |
174 | } | |
175 | } | |
176 | } | |
177 | ||
08ae95f4 NP |
178 | #ifdef CONFIG_NO_HZ_FULL |
179 | static void giveup_do_timer(void *info) | |
180 | { | |
181 | int cpu = *(unsigned int *)info; | |
182 | ||
183 | WARN_ON(tick_do_timer_cpu != smp_processor_id()); | |
184 | ||
185 | tick_do_timer_cpu = cpu; | |
186 | } | |
187 | ||
188 | static void tick_take_do_timer_from_boot(void) | |
189 | { | |
190 | int cpu = smp_processor_id(); | |
191 | int from = tick_do_timer_boot_cpu; | |
192 | ||
193 | if (from >= 0 && from != cpu) | |
194 | smp_call_function_single(from, giveup_do_timer, &cpu, 1); | |
195 | } | |
196 | #endif | |
197 | ||
906568c9 TG |
198 | /* |
199 | * Setup the tick device | |
200 | */ | |
201 | static void tick_setup_device(struct tick_device *td, | |
202 | struct clock_event_device *newdev, int cpu, | |
0de26520 | 203 | const struct cpumask *cpumask) |
906568c9 | 204 | { |
906568c9 | 205 | void (*handler)(struct clock_event_device *) = NULL; |
8b0e1953 | 206 | ktime_t next_event = 0; |
906568c9 TG |
207 | |
208 | /* | |
209 | * First device setup ? | |
210 | */ | |
211 | if (!td->evtdev) { | |
212 | /* | |
213 | * If no cpu took the do_timer update, assign it to | |
214 | * this cpu: | |
215 | */ | |
6441402b | 216 | if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) { |
08ae95f4 NP |
217 | tick_do_timer_cpu = cpu; |
218 | ||
906568c9 | 219 | tick_next_period = ktime_get(); |
8b0e1953 | 220 | tick_period = NSEC_PER_SEC / HZ; |
08ae95f4 NP |
221 | #ifdef CONFIG_NO_HZ_FULL |
222 | /* | |
223 | * The boot CPU may be nohz_full, in which case set | |
224 | * tick_do_timer_boot_cpu so the first housekeeping | |
225 | * secondary that comes up will take do_timer from | |
226 | * us. | |
227 | */ | |
228 | if (tick_nohz_full_cpu(cpu)) | |
229 | tick_do_timer_boot_cpu = cpu; | |
230 | ||
231 | } else if (tick_do_timer_boot_cpu != -1 && | |
232 | !tick_nohz_full_cpu(cpu)) { | |
233 | tick_take_do_timer_from_boot(); | |
234 | tick_do_timer_boot_cpu = -1; | |
235 | WARN_ON(tick_do_timer_cpu != cpu); | |
236 | #endif | |
906568c9 TG |
237 | } |
238 | ||
239 | /* | |
240 | * Startup in periodic mode first. | |
241 | */ | |
242 | td->mode = TICKDEV_MODE_PERIODIC; | |
243 | } else { | |
244 | handler = td->evtdev->event_handler; | |
245 | next_event = td->evtdev->next_event; | |
7c1e7689 | 246 | td->evtdev->event_handler = clockevents_handle_noop; |
906568c9 TG |
247 | } |
248 | ||
249 | td->evtdev = newdev; | |
250 | ||
251 | /* | |
252 | * When the device is not per cpu, pin the interrupt to the | |
253 | * current cpu: | |
254 | */ | |
320ab2b0 | 255 | if (!cpumask_equal(newdev->cpumask, cpumask)) |
0de26520 | 256 | irq_set_affinity(newdev->irq, cpumask); |
906568c9 | 257 | |
f8381cba TG |
258 | /* |
259 | * When global broadcasting is active, check if the current | |
260 | * device is registered as a placeholder for broadcast mode. | |
261 | * This allows us to handle this x86 misfeature in a generic | |
07bd1172 TG |
262 | * way. This function also returns !=0 when we keep the |
263 | * current active broadcast state for this CPU. | |
f8381cba TG |
264 | */ |
265 | if (tick_device_uses_broadcast(newdev, cpu)) | |
266 | return; | |
267 | ||
906568c9 TG |
268 | if (td->mode == TICKDEV_MODE_PERIODIC) |
269 | tick_setup_periodic(newdev, 0); | |
79bf2bb3 TG |
270 | else |
271 | tick_setup_oneshot(newdev, handler, next_event); | |
906568c9 TG |
272 | } |
273 | ||
03e13cf5 TG |
274 | void tick_install_replacement(struct clock_event_device *newdev) |
275 | { | |
22127e93 | 276 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); |
03e13cf5 TG |
277 | int cpu = smp_processor_id(); |
278 | ||
279 | clockevents_exchange_device(td->evtdev, newdev); | |
280 | tick_setup_device(td, newdev, cpu, cpumask_of(cpu)); | |
281 | if (newdev->features & CLOCK_EVT_FEAT_ONESHOT) | |
282 | tick_oneshot_notify(); | |
283 | } | |
284 | ||
45cb8e01 TG |
285 | static bool tick_check_percpu(struct clock_event_device *curdev, |
286 | struct clock_event_device *newdev, int cpu) | |
287 | { | |
288 | if (!cpumask_test_cpu(cpu, newdev->cpumask)) | |
289 | return false; | |
290 | if (cpumask_equal(newdev->cpumask, cpumask_of(cpu))) | |
291 | return true; | |
292 | /* Check if irq affinity can be set */ | |
293 | if (newdev->irq >= 0 && !irq_can_set_affinity(newdev->irq)) | |
294 | return false; | |
295 | /* Prefer an existing cpu local device */ | |
296 | if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu))) | |
297 | return false; | |
298 | return true; | |
299 | } | |
300 | ||
301 | static bool tick_check_preferred(struct clock_event_device *curdev, | |
302 | struct clock_event_device *newdev) | |
303 | { | |
304 | /* Prefer oneshot capable device */ | |
305 | if (!(newdev->features & CLOCK_EVT_FEAT_ONESHOT)) { | |
306 | if (curdev && (curdev->features & CLOCK_EVT_FEAT_ONESHOT)) | |
307 | return false; | |
308 | if (tick_oneshot_mode_active()) | |
309 | return false; | |
310 | } | |
311 | ||
70e5975d SB |
312 | /* |
313 | * Use the higher rated one, but prefer a CPU local device with a lower | |
314 | * rating than a non-CPU local device | |
315 | */ | |
316 | return !curdev || | |
317 | newdev->rating > curdev->rating || | |
5b5ccbc2 | 318 | !cpumask_equal(curdev->cpumask, newdev->cpumask); |
45cb8e01 TG |
319 | } |
320 | ||
03e13cf5 TG |
321 | /* |
322 | * Check whether the new device is a better fit than curdev. curdev | |
323 | * can be NULL ! | |
324 | */ | |
325 | bool tick_check_replacement(struct clock_event_device *curdev, | |
326 | struct clock_event_device *newdev) | |
327 | { | |
521c4299 | 328 | if (!tick_check_percpu(curdev, newdev, smp_processor_id())) |
03e13cf5 TG |
329 | return false; |
330 | ||
331 | return tick_check_preferred(curdev, newdev); | |
332 | } | |
333 | ||
906568c9 | 334 | /* |
7126cac4 TG |
335 | * Check, if the new registered device should be used. Called with |
336 | * clockevents_lock held and interrupts disabled. | |
906568c9 | 337 | */ |
7172a286 | 338 | void tick_check_new_device(struct clock_event_device *newdev) |
906568c9 TG |
339 | { |
340 | struct clock_event_device *curdev; | |
341 | struct tick_device *td; | |
7172a286 | 342 | int cpu; |
906568c9 TG |
343 | |
344 | cpu = smp_processor_id(); | |
906568c9 TG |
345 | td = &per_cpu(tick_cpu_device, cpu); |
346 | curdev = td->evtdev; | |
906568c9 TG |
347 | |
348 | /* cpu local device ? */ | |
45cb8e01 TG |
349 | if (!tick_check_percpu(curdev, newdev, cpu)) |
350 | goto out_bc; | |
906568c9 | 351 | |
45cb8e01 TG |
352 | /* Preference decision */ |
353 | if (!tick_check_preferred(curdev, newdev)) | |
354 | goto out_bc; | |
906568c9 | 355 | |
ccf33d68 TG |
356 | if (!try_module_get(newdev->owner)) |
357 | return; | |
358 | ||
906568c9 TG |
359 | /* |
360 | * Replace the eventually existing device by the new | |
f8381cba TG |
361 | * device. If the current device is the broadcast device, do |
362 | * not give it back to the clockevents layer ! | |
906568c9 | 363 | */ |
f8381cba | 364 | if (tick_is_broadcast_device(curdev)) { |
2344abbc | 365 | clockevents_shutdown(curdev); |
f8381cba TG |
366 | curdev = NULL; |
367 | } | |
906568c9 | 368 | clockevents_exchange_device(curdev, newdev); |
6b954823 | 369 | tick_setup_device(td, newdev, cpu, cpumask_of(cpu)); |
79bf2bb3 TG |
370 | if (newdev->features & CLOCK_EVT_FEAT_ONESHOT) |
371 | tick_oneshot_notify(); | |
7172a286 | 372 | return; |
f8381cba TG |
373 | |
374 | out_bc: | |
375 | /* | |
376 | * Can the new device be used as a broadcast device ? | |
377 | */ | |
7172a286 | 378 | tick_install_broadcast_device(newdev); |
906568c9 TG |
379 | } |
380 | ||
f32dd117 TG |
381 | /** |
382 | * tick_broadcast_oneshot_control - Enter/exit broadcast oneshot mode | |
383 | * @state: The target state (enter/exit) | |
384 | * | |
385 | * The system enters/leaves a state, where affected devices might stop | |
386 | * Returns 0 on success, -EBUSY if the cpu is used to broadcast wakeups. | |
387 | * | |
388 | * Called with interrupts disabled, so clockevents_lock is not | |
389 | * required here because the local clock event device cannot go away | |
390 | * under us. | |
391 | */ | |
392 | int tick_broadcast_oneshot_control(enum tick_broadcast_state state) | |
393 | { | |
394 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); | |
395 | ||
396 | if (!(td->evtdev->features & CLOCK_EVT_FEAT_C3STOP)) | |
397 | return 0; | |
398 | ||
399 | return __tick_broadcast_oneshot_control(state); | |
400 | } | |
0f447051 | 401 | EXPORT_SYMBOL_GPL(tick_broadcast_oneshot_control); |
f32dd117 | 402 | |
52c063d1 | 403 | #ifdef CONFIG_HOTPLUG_CPU |
94df7de0 SD |
404 | /* |
405 | * Transfer the do_timer job away from a dying cpu. | |
406 | * | |
52c063d1 TG |
407 | * Called with interrupts disabled. Not locking required. If |
408 | * tick_do_timer_cpu is owned by this cpu, nothing can change it. | |
94df7de0 | 409 | */ |
52c063d1 | 410 | void tick_handover_do_timer(void) |
94df7de0 | 411 | { |
52c063d1 | 412 | if (tick_do_timer_cpu == smp_processor_id()) { |
94df7de0 SD |
413 | int cpu = cpumask_first(cpu_online_mask); |
414 | ||
415 | tick_do_timer_cpu = (cpu < nr_cpu_ids) ? cpu : | |
416 | TICK_DO_TIMER_NONE; | |
417 | } | |
418 | } | |
419 | ||
906568c9 TG |
420 | /* |
421 | * Shutdown an event device on a given cpu: | |
422 | * | |
423 | * This is called on a life CPU, when a CPU is dead. So we cannot | |
424 | * access the hardware device itself. | |
425 | * We just set the mode and remove it from the lists. | |
426 | */ | |
a49b116d | 427 | void tick_shutdown(unsigned int cpu) |
906568c9 | 428 | { |
a49b116d | 429 | struct tick_device *td = &per_cpu(tick_cpu_device, cpu); |
906568c9 | 430 | struct clock_event_device *dev = td->evtdev; |
906568c9 | 431 | |
906568c9 TG |
432 | td->mode = TICKDEV_MODE_PERIODIC; |
433 | if (dev) { | |
434 | /* | |
435 | * Prevent that the clock events layer tries to call | |
436 | * the set mode function! | |
437 | */ | |
051ebd10 | 438 | clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED); |
906568c9 | 439 | clockevents_exchange_device(dev, NULL); |
6f7a05d7 | 440 | dev->event_handler = clockevents_handle_noop; |
906568c9 TG |
441 | td->evtdev = NULL; |
442 | } | |
906568c9 | 443 | } |
a49b116d | 444 | #endif |
906568c9 | 445 | |
4ffee521 | 446 | /** |
f46481d0 | 447 | * tick_suspend_local - Suspend the local tick device |
4ffee521 | 448 | * |
f46481d0 | 449 | * Called from the local cpu for freeze with interrupts disabled. |
4ffee521 TG |
450 | * |
451 | * No locks required. Nothing can change the per cpu device. | |
452 | */ | |
7270d11c | 453 | void tick_suspend_local(void) |
6321dd60 | 454 | { |
22127e93 | 455 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); |
6321dd60 | 456 | |
2344abbc | 457 | clockevents_shutdown(td->evtdev); |
6321dd60 TG |
458 | } |
459 | ||
4ffee521 | 460 | /** |
f46481d0 | 461 | * tick_resume_local - Resume the local tick device |
4ffee521 | 462 | * |
f46481d0 | 463 | * Called from the local CPU for unfreeze or XEN resume magic. |
4ffee521 TG |
464 | * |
465 | * No locks required. Nothing can change the per cpu device. | |
466 | */ | |
f46481d0 | 467 | void tick_resume_local(void) |
6321dd60 | 468 | { |
f46481d0 TG |
469 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); |
470 | bool broadcast = tick_resume_check_broadcast(); | |
6321dd60 | 471 | |
554ef387 | 472 | clockevents_tick_resume(td->evtdev); |
18de5bc4 TG |
473 | if (!broadcast) { |
474 | if (td->mode == TICKDEV_MODE_PERIODIC) | |
475 | tick_setup_periodic(td->evtdev, 0); | |
476 | else | |
477 | tick_resume_oneshot(); | |
478 | } | |
6321dd60 TG |
479 | } |
480 | ||
f46481d0 TG |
481 | /** |
482 | * tick_suspend - Suspend the tick and the broadcast device | |
483 | * | |
484 | * Called from syscore_suspend() via timekeeping_suspend with only one | |
485 | * CPU online and interrupts disabled or from tick_unfreeze() under | |
486 | * tick_freeze_lock. | |
487 | * | |
488 | * No locks required. Nothing can change the per cpu device. | |
489 | */ | |
490 | void tick_suspend(void) | |
491 | { | |
492 | tick_suspend_local(); | |
493 | tick_suspend_broadcast(); | |
494 | } | |
495 | ||
496 | /** | |
497 | * tick_resume - Resume the tick and the broadcast device | |
498 | * | |
499 | * Called from syscore_resume() via timekeeping_resume with only one | |
500 | * CPU online and interrupts disabled. | |
501 | * | |
502 | * No locks required. Nothing can change the per cpu device. | |
503 | */ | |
504 | void tick_resume(void) | |
505 | { | |
506 | tick_resume_broadcast(); | |
507 | tick_resume_local(); | |
508 | } | |
509 | ||
87e9b9f1 | 510 | #ifdef CONFIG_SUSPEND |
124cf911 RW |
511 | static DEFINE_RAW_SPINLOCK(tick_freeze_lock); |
512 | static unsigned int tick_freeze_depth; | |
513 | ||
514 | /** | |
515 | * tick_freeze - Suspend the local tick and (possibly) timekeeping. | |
516 | * | |
517 | * Check if this is the last online CPU executing the function and if so, | |
518 | * suspend timekeeping. Otherwise suspend the local tick. | |
519 | * | |
520 | * Call with interrupts disabled. Must be balanced with %tick_unfreeze(). | |
521 | * Interrupts must not be enabled before the subsequent %tick_unfreeze(). | |
522 | */ | |
523 | void tick_freeze(void) | |
524 | { | |
525 | raw_spin_lock(&tick_freeze_lock); | |
526 | ||
527 | tick_freeze_depth++; | |
75e0678e RW |
528 | if (tick_freeze_depth == num_online_cpus()) { |
529 | trace_suspend_resume(TPS("timekeeping_freeze"), | |
530 | smp_processor_id(), true); | |
c1a957d1 | 531 | system_state = SYSTEM_SUSPEND; |
3f2552f7 | 532 | sched_clock_suspend(); |
124cf911 | 533 | timekeeping_suspend(); |
75e0678e | 534 | } else { |
f46481d0 | 535 | tick_suspend_local(); |
75e0678e | 536 | } |
124cf911 RW |
537 | |
538 | raw_spin_unlock(&tick_freeze_lock); | |
539 | } | |
540 | ||
541 | /** | |
542 | * tick_unfreeze - Resume the local tick and (possibly) timekeeping. | |
543 | * | |
544 | * Check if this is the first CPU executing the function and if so, resume | |
545 | * timekeeping. Otherwise resume the local tick. | |
546 | * | |
547 | * Call with interrupts disabled. Must be balanced with %tick_freeze(). | |
548 | * Interrupts must not be enabled after the preceding %tick_freeze(). | |
549 | */ | |
550 | void tick_unfreeze(void) | |
551 | { | |
552 | raw_spin_lock(&tick_freeze_lock); | |
553 | ||
75e0678e | 554 | if (tick_freeze_depth == num_online_cpus()) { |
124cf911 | 555 | timekeeping_resume(); |
3f2552f7 | 556 | sched_clock_resume(); |
c1a957d1 | 557 | system_state = SYSTEM_RUNNING; |
75e0678e RW |
558 | trace_suspend_resume(TPS("timekeeping_freeze"), |
559 | smp_processor_id(), false); | |
560 | } else { | |
422fe750 | 561 | tick_resume_local(); |
75e0678e | 562 | } |
124cf911 RW |
563 | |
564 | tick_freeze_depth--; | |
565 | ||
566 | raw_spin_unlock(&tick_freeze_lock); | |
567 | } | |
87e9b9f1 | 568 | #endif /* CONFIG_SUSPEND */ |
124cf911 | 569 | |
906568c9 TG |
570 | /** |
571 | * tick_init - initialize the tick control | |
906568c9 TG |
572 | */ |
573 | void __init tick_init(void) | |
574 | { | |
b352bc1c | 575 | tick_broadcast_init(); |
a80e49e2 | 576 | tick_nohz_init(); |
906568c9 | 577 | } |