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Commit | Line | Data |
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1 | /* | |
2 | * Generic helpers for smp ipi calls | |
3 | * | |
4 | * (C) Jens Axboe <jens.axboe@oracle.com> 2008 | |
5 | */ | |
6 | #include <linux/irq_work.h> | |
7 | #include <linux/rcupdate.h> | |
8 | #include <linux/rculist.h> | |
9 | #include <linux/kernel.h> | |
10 | #include <linux/export.h> | |
11 | #include <linux/percpu.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/gfp.h> | |
14 | #include <linux/smp.h> | |
15 | #include <linux/cpu.h> | |
16 | #include <linux/sched.h> | |
17 | ||
18 | #include "smpboot.h" | |
19 | ||
20 | enum { | |
21 | CSD_FLAG_LOCK = 0x01, | |
22 | CSD_FLAG_SYNCHRONOUS = 0x02, | |
23 | }; | |
24 | ||
25 | struct call_function_data { | |
26 | struct call_single_data __percpu *csd; | |
27 | cpumask_var_t cpumask; | |
28 | }; | |
29 | ||
30 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_function_data, cfd_data); | |
31 | ||
32 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head, call_single_queue); | |
33 | ||
34 | static void flush_smp_call_function_queue(bool warn_cpu_offline); | |
35 | ||
36 | int smpcfd_prepare_cpu(unsigned int cpu) | |
37 | { | |
38 | struct call_function_data *cfd = &per_cpu(cfd_data, cpu); | |
39 | ||
40 | if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL, | |
41 | cpu_to_node(cpu))) | |
42 | return -ENOMEM; | |
43 | cfd->csd = alloc_percpu(struct call_single_data); | |
44 | if (!cfd->csd) { | |
45 | free_cpumask_var(cfd->cpumask); | |
46 | return -ENOMEM; | |
47 | } | |
48 | ||
49 | return 0; | |
50 | } | |
51 | ||
52 | int smpcfd_dead_cpu(unsigned int cpu) | |
53 | { | |
54 | struct call_function_data *cfd = &per_cpu(cfd_data, cpu); | |
55 | ||
56 | free_cpumask_var(cfd->cpumask); | |
57 | free_percpu(cfd->csd); | |
58 | return 0; | |
59 | } | |
60 | ||
61 | int smpcfd_dying_cpu(unsigned int cpu) | |
62 | { | |
63 | /* | |
64 | * The IPIs for the smp-call-function callbacks queued by other | |
65 | * CPUs might arrive late, either due to hardware latencies or | |
66 | * because this CPU disabled interrupts (inside stop-machine) | |
67 | * before the IPIs were sent. So flush out any pending callbacks | |
68 | * explicitly (without waiting for the IPIs to arrive), to | |
69 | * ensure that the outgoing CPU doesn't go offline with work | |
70 | * still pending. | |
71 | */ | |
72 | flush_smp_call_function_queue(false); | |
73 | return 0; | |
74 | } | |
75 | ||
76 | void __init call_function_init(void) | |
77 | { | |
78 | int i; | |
79 | ||
80 | for_each_possible_cpu(i) | |
81 | init_llist_head(&per_cpu(call_single_queue, i)); | |
82 | ||
83 | smpcfd_prepare_cpu(smp_processor_id()); | |
84 | } | |
85 | ||
86 | /* | |
87 | * csd_lock/csd_unlock used to serialize access to per-cpu csd resources | |
88 | * | |
89 | * For non-synchronous ipi calls the csd can still be in use by the | |
90 | * previous function call. For multi-cpu calls its even more interesting | |
91 | * as we'll have to ensure no other cpu is observing our csd. | |
92 | */ | |
93 | static __always_inline void csd_lock_wait(struct call_single_data *csd) | |
94 | { | |
95 | smp_cond_load_acquire(&csd->flags, !(VAL & CSD_FLAG_LOCK)); | |
96 | } | |
97 | ||
98 | static __always_inline void csd_lock(struct call_single_data *csd) | |
99 | { | |
100 | csd_lock_wait(csd); | |
101 | csd->flags |= CSD_FLAG_LOCK; | |
102 | ||
103 | /* | |
104 | * prevent CPU from reordering the above assignment | |
105 | * to ->flags with any subsequent assignments to other | |
106 | * fields of the specified call_single_data structure: | |
107 | */ | |
108 | smp_wmb(); | |
109 | } | |
110 | ||
111 | static __always_inline void csd_unlock(struct call_single_data *csd) | |
112 | { | |
113 | WARN_ON(!(csd->flags & CSD_FLAG_LOCK)); | |
114 | ||
115 | /* | |
116 | * ensure we're all done before releasing data: | |
117 | */ | |
118 | smp_store_release(&csd->flags, 0); | |
119 | } | |
120 | ||
121 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data); | |
122 | ||
123 | /* | |
124 | * Insert a previously allocated call_single_data element | |
125 | * for execution on the given CPU. data must already have | |
126 | * ->func, ->info, and ->flags set. | |
127 | */ | |
128 | static int generic_exec_single(int cpu, struct call_single_data *csd, | |
129 | smp_call_func_t func, void *info) | |
130 | { | |
131 | if (cpu == smp_processor_id()) { | |
132 | unsigned long flags; | |
133 | ||
134 | /* | |
135 | * We can unlock early even for the synchronous on-stack case, | |
136 | * since we're doing this from the same CPU.. | |
137 | */ | |
138 | csd_unlock(csd); | |
139 | local_irq_save(flags); | |
140 | func(info); | |
141 | local_irq_restore(flags); | |
142 | return 0; | |
143 | } | |
144 | ||
145 | ||
146 | if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu)) { | |
147 | csd_unlock(csd); | |
148 | return -ENXIO; | |
149 | } | |
150 | ||
151 | csd->func = func; | |
152 | csd->info = info; | |
153 | ||
154 | /* | |
155 | * The list addition should be visible before sending the IPI | |
156 | * handler locks the list to pull the entry off it because of | |
157 | * normal cache coherency rules implied by spinlocks. | |
158 | * | |
159 | * If IPIs can go out of order to the cache coherency protocol | |
160 | * in an architecture, sufficient synchronisation should be added | |
161 | * to arch code to make it appear to obey cache coherency WRT | |
162 | * locking and barrier primitives. Generic code isn't really | |
163 | * equipped to do the right thing... | |
164 | */ | |
165 | if (llist_add(&csd->llist, &per_cpu(call_single_queue, cpu))) | |
166 | arch_send_call_function_single_ipi(cpu); | |
167 | ||
168 | return 0; | |
169 | } | |
170 | ||
171 | /** | |
172 | * generic_smp_call_function_single_interrupt - Execute SMP IPI callbacks | |
173 | * | |
174 | * Invoked by arch to handle an IPI for call function single. | |
175 | * Must be called with interrupts disabled. | |
176 | */ | |
177 | void generic_smp_call_function_single_interrupt(void) | |
178 | { | |
179 | flush_smp_call_function_queue(true); | |
180 | } | |
181 | ||
182 | /** | |
183 | * flush_smp_call_function_queue - Flush pending smp-call-function callbacks | |
184 | * | |
185 | * @warn_cpu_offline: If set to 'true', warn if callbacks were queued on an | |
186 | * offline CPU. Skip this check if set to 'false'. | |
187 | * | |
188 | * Flush any pending smp-call-function callbacks queued on this CPU. This is | |
189 | * invoked by the generic IPI handler, as well as by a CPU about to go offline, | |
190 | * to ensure that all pending IPI callbacks are run before it goes completely | |
191 | * offline. | |
192 | * | |
193 | * Loop through the call_single_queue and run all the queued callbacks. | |
194 | * Must be called with interrupts disabled. | |
195 | */ | |
196 | static void flush_smp_call_function_queue(bool warn_cpu_offline) | |
197 | { | |
198 | struct llist_head *head; | |
199 | struct llist_node *entry; | |
200 | struct call_single_data *csd, *csd_next; | |
201 | static bool warned; | |
202 | ||
203 | WARN_ON(!irqs_disabled()); | |
204 | ||
205 | head = this_cpu_ptr(&call_single_queue); | |
206 | entry = llist_del_all(head); | |
207 | entry = llist_reverse_order(entry); | |
208 | ||
209 | /* There shouldn't be any pending callbacks on an offline CPU. */ | |
210 | if (unlikely(warn_cpu_offline && !cpu_online(smp_processor_id()) && | |
211 | !warned && !llist_empty(head))) { | |
212 | warned = true; | |
213 | WARN(1, "IPI on offline CPU %d\n", smp_processor_id()); | |
214 | ||
215 | /* | |
216 | * We don't have to use the _safe() variant here | |
217 | * because we are not invoking the IPI handlers yet. | |
218 | */ | |
219 | llist_for_each_entry(csd, entry, llist) | |
220 | pr_warn("IPI callback %pS sent to offline CPU\n", | |
221 | csd->func); | |
222 | } | |
223 | ||
224 | llist_for_each_entry_safe(csd, csd_next, entry, llist) { | |
225 | smp_call_func_t func = csd->func; | |
226 | void *info = csd->info; | |
227 | ||
228 | /* Do we wait until *after* callback? */ | |
229 | if (csd->flags & CSD_FLAG_SYNCHRONOUS) { | |
230 | func(info); | |
231 | csd_unlock(csd); | |
232 | } else { | |
233 | csd_unlock(csd); | |
234 | func(info); | |
235 | } | |
236 | } | |
237 | ||
238 | /* | |
239 | * Handle irq works queued remotely by irq_work_queue_on(). | |
240 | * Smp functions above are typically synchronous so they | |
241 | * better run first since some other CPUs may be busy waiting | |
242 | * for them. | |
243 | */ | |
244 | irq_work_run(); | |
245 | } | |
246 | ||
247 | /* | |
248 | * smp_call_function_single - Run a function on a specific CPU | |
249 | * @func: The function to run. This must be fast and non-blocking. | |
250 | * @info: An arbitrary pointer to pass to the function. | |
251 | * @wait: If true, wait until function has completed on other CPUs. | |
252 | * | |
253 | * Returns 0 on success, else a negative status code. | |
254 | */ | |
255 | int smp_call_function_single(int cpu, smp_call_func_t func, void *info, | |
256 | int wait) | |
257 | { | |
258 | struct call_single_data *csd; | |
259 | struct call_single_data csd_stack = { .flags = CSD_FLAG_LOCK | CSD_FLAG_SYNCHRONOUS }; | |
260 | int this_cpu; | |
261 | int err; | |
262 | ||
263 | /* | |
264 | * prevent preemption and reschedule on another processor, | |
265 | * as well as CPU removal | |
266 | */ | |
267 | this_cpu = get_cpu(); | |
268 | ||
269 | /* | |
270 | * Can deadlock when called with interrupts disabled. | |
271 | * We allow cpu's that are not yet online though, as no one else can | |
272 | * send smp call function interrupt to this cpu and as such deadlocks | |
273 | * can't happen. | |
274 | */ | |
275 | WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() | |
276 | && !oops_in_progress); | |
277 | ||
278 | csd = &csd_stack; | |
279 | if (!wait) { | |
280 | csd = this_cpu_ptr(&csd_data); | |
281 | csd_lock(csd); | |
282 | } | |
283 | ||
284 | err = generic_exec_single(cpu, csd, func, info); | |
285 | ||
286 | if (wait) | |
287 | csd_lock_wait(csd); | |
288 | ||
289 | put_cpu(); | |
290 | ||
291 | return err; | |
292 | } | |
293 | EXPORT_SYMBOL(smp_call_function_single); | |
294 | ||
295 | /** | |
296 | * smp_call_function_single_async(): Run an asynchronous function on a | |
297 | * specific CPU. | |
298 | * @cpu: The CPU to run on. | |
299 | * @csd: Pre-allocated and setup data structure | |
300 | * | |
301 | * Like smp_call_function_single(), but the call is asynchonous and | |
302 | * can thus be done from contexts with disabled interrupts. | |
303 | * | |
304 | * The caller passes his own pre-allocated data structure | |
305 | * (ie: embedded in an object) and is responsible for synchronizing it | |
306 | * such that the IPIs performed on the @csd are strictly serialized. | |
307 | * | |
308 | * NOTE: Be careful, there is unfortunately no current debugging facility to | |
309 | * validate the correctness of this serialization. | |
310 | */ | |
311 | int smp_call_function_single_async(int cpu, struct call_single_data *csd) | |
312 | { | |
313 | int err = 0; | |
314 | ||
315 | preempt_disable(); | |
316 | ||
317 | /* We could deadlock if we have to wait here with interrupts disabled! */ | |
318 | if (WARN_ON_ONCE(csd->flags & CSD_FLAG_LOCK)) | |
319 | csd_lock_wait(csd); | |
320 | ||
321 | csd->flags = CSD_FLAG_LOCK; | |
322 | smp_wmb(); | |
323 | ||
324 | err = generic_exec_single(cpu, csd, csd->func, csd->info); | |
325 | preempt_enable(); | |
326 | ||
327 | return err; | |
328 | } | |
329 | EXPORT_SYMBOL_GPL(smp_call_function_single_async); | |
330 | ||
331 | /* | |
332 | * smp_call_function_any - Run a function on any of the given cpus | |
333 | * @mask: The mask of cpus it can run on. | |
334 | * @func: The function to run. This must be fast and non-blocking. | |
335 | * @info: An arbitrary pointer to pass to the function. | |
336 | * @wait: If true, wait until function has completed. | |
337 | * | |
338 | * Returns 0 on success, else a negative status code (if no cpus were online). | |
339 | * | |
340 | * Selection preference: | |
341 | * 1) current cpu if in @mask | |
342 | * 2) any cpu of current node if in @mask | |
343 | * 3) any other online cpu in @mask | |
344 | */ | |
345 | int smp_call_function_any(const struct cpumask *mask, | |
346 | smp_call_func_t func, void *info, int wait) | |
347 | { | |
348 | unsigned int cpu; | |
349 | const struct cpumask *nodemask; | |
350 | int ret; | |
351 | ||
352 | /* Try for same CPU (cheapest) */ | |
353 | cpu = get_cpu(); | |
354 | if (cpumask_test_cpu(cpu, mask)) | |
355 | goto call; | |
356 | ||
357 | /* Try for same node. */ | |
358 | nodemask = cpumask_of_node(cpu_to_node(cpu)); | |
359 | for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids; | |
360 | cpu = cpumask_next_and(cpu, nodemask, mask)) { | |
361 | if (cpu_online(cpu)) | |
362 | goto call; | |
363 | } | |
364 | ||
365 | /* Any online will do: smp_call_function_single handles nr_cpu_ids. */ | |
366 | cpu = cpumask_any_and(mask, cpu_online_mask); | |
367 | call: | |
368 | ret = smp_call_function_single(cpu, func, info, wait); | |
369 | put_cpu(); | |
370 | return ret; | |
371 | } | |
372 | EXPORT_SYMBOL_GPL(smp_call_function_any); | |
373 | ||
374 | /** | |
375 | * smp_call_function_many(): Run a function on a set of other CPUs. | |
376 | * @mask: The set of cpus to run on (only runs on online subset). | |
377 | * @func: The function to run. This must be fast and non-blocking. | |
378 | * @info: An arbitrary pointer to pass to the function. | |
379 | * @wait: If true, wait (atomically) until function has completed | |
380 | * on other CPUs. | |
381 | * | |
382 | * If @wait is true, then returns once @func has returned. | |
383 | * | |
384 | * You must not call this function with disabled interrupts or from a | |
385 | * hardware interrupt handler or from a bottom half handler. Preemption | |
386 | * must be disabled when calling this function. | |
387 | */ | |
388 | void smp_call_function_many(const struct cpumask *mask, | |
389 | smp_call_func_t func, void *info, bool wait) | |
390 | { | |
391 | struct call_function_data *cfd; | |
392 | int cpu, next_cpu, this_cpu = smp_processor_id(); | |
393 | ||
394 | /* | |
395 | * Can deadlock when called with interrupts disabled. | |
396 | * We allow cpu's that are not yet online though, as no one else can | |
397 | * send smp call function interrupt to this cpu and as such deadlocks | |
398 | * can't happen. | |
399 | */ | |
400 | WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() | |
401 | && !oops_in_progress && !early_boot_irqs_disabled); | |
402 | ||
403 | /* Try to fastpath. So, what's a CPU they want? Ignoring this one. */ | |
404 | cpu = cpumask_first_and(mask, cpu_online_mask); | |
405 | if (cpu == this_cpu) | |
406 | cpu = cpumask_next_and(cpu, mask, cpu_online_mask); | |
407 | ||
408 | /* No online cpus? We're done. */ | |
409 | if (cpu >= nr_cpu_ids) | |
410 | return; | |
411 | ||
412 | /* Do we have another CPU which isn't us? */ | |
413 | next_cpu = cpumask_next_and(cpu, mask, cpu_online_mask); | |
414 | if (next_cpu == this_cpu) | |
415 | next_cpu = cpumask_next_and(next_cpu, mask, cpu_online_mask); | |
416 | ||
417 | /* Fastpath: do that cpu by itself. */ | |
418 | if (next_cpu >= nr_cpu_ids) { | |
419 | smp_call_function_single(cpu, func, info, wait); | |
420 | return; | |
421 | } | |
422 | ||
423 | cfd = this_cpu_ptr(&cfd_data); | |
424 | ||
425 | cpumask_and(cfd->cpumask, mask, cpu_online_mask); | |
426 | cpumask_clear_cpu(this_cpu, cfd->cpumask); | |
427 | ||
428 | /* Some callers race with other cpus changing the passed mask */ | |
429 | if (unlikely(!cpumask_weight(cfd->cpumask))) | |
430 | return; | |
431 | ||
432 | for_each_cpu(cpu, cfd->cpumask) { | |
433 | struct call_single_data *csd = per_cpu_ptr(cfd->csd, cpu); | |
434 | ||
435 | csd_lock(csd); | |
436 | if (wait) | |
437 | csd->flags |= CSD_FLAG_SYNCHRONOUS; | |
438 | csd->func = func; | |
439 | csd->info = info; | |
440 | llist_add(&csd->llist, &per_cpu(call_single_queue, cpu)); | |
441 | } | |
442 | ||
443 | /* Send a message to all CPUs in the map */ | |
444 | arch_send_call_function_ipi_mask(cfd->cpumask); | |
445 | ||
446 | if (wait) { | |
447 | for_each_cpu(cpu, cfd->cpumask) { | |
448 | struct call_single_data *csd; | |
449 | ||
450 | csd = per_cpu_ptr(cfd->csd, cpu); | |
451 | csd_lock_wait(csd); | |
452 | } | |
453 | } | |
454 | } | |
455 | EXPORT_SYMBOL(smp_call_function_many); | |
456 | ||
457 | /** | |
458 | * smp_call_function(): Run a function on all other CPUs. | |
459 | * @func: The function to run. This must be fast and non-blocking. | |
460 | * @info: An arbitrary pointer to pass to the function. | |
461 | * @wait: If true, wait (atomically) until function has completed | |
462 | * on other CPUs. | |
463 | * | |
464 | * Returns 0. | |
465 | * | |
466 | * If @wait is true, then returns once @func has returned; otherwise | |
467 | * it returns just before the target cpu calls @func. | |
468 | * | |
469 | * You must not call this function with disabled interrupts or from a | |
470 | * hardware interrupt handler or from a bottom half handler. | |
471 | */ | |
472 | int smp_call_function(smp_call_func_t func, void *info, int wait) | |
473 | { | |
474 | preempt_disable(); | |
475 | smp_call_function_many(cpu_online_mask, func, info, wait); | |
476 | preempt_enable(); | |
477 | ||
478 | return 0; | |
479 | } | |
480 | EXPORT_SYMBOL(smp_call_function); | |
481 | ||
482 | /* Setup configured maximum number of CPUs to activate */ | |
483 | unsigned int setup_max_cpus = NR_CPUS; | |
484 | EXPORT_SYMBOL(setup_max_cpus); | |
485 | ||
486 | ||
487 | /* | |
488 | * Setup routine for controlling SMP activation | |
489 | * | |
490 | * Command-line option of "nosmp" or "maxcpus=0" will disable SMP | |
491 | * activation entirely (the MPS table probe still happens, though). | |
492 | * | |
493 | * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer | |
494 | * greater than 0, limits the maximum number of CPUs activated in | |
495 | * SMP mode to <NUM>. | |
496 | */ | |
497 | ||
498 | void __weak arch_disable_smp_support(void) { } | |
499 | ||
500 | static int __init nosmp(char *str) | |
501 | { | |
502 | setup_max_cpus = 0; | |
503 | arch_disable_smp_support(); | |
504 | ||
505 | return 0; | |
506 | } | |
507 | ||
508 | early_param("nosmp", nosmp); | |
509 | ||
510 | /* this is hard limit */ | |
511 | static int __init nrcpus(char *str) | |
512 | { | |
513 | int nr_cpus; | |
514 | ||
515 | get_option(&str, &nr_cpus); | |
516 | if (nr_cpus > 0 && nr_cpus < nr_cpu_ids) | |
517 | nr_cpu_ids = nr_cpus; | |
518 | ||
519 | return 0; | |
520 | } | |
521 | ||
522 | early_param("nr_cpus", nrcpus); | |
523 | ||
524 | static int __init maxcpus(char *str) | |
525 | { | |
526 | get_option(&str, &setup_max_cpus); | |
527 | if (setup_max_cpus == 0) | |
528 | arch_disable_smp_support(); | |
529 | ||
530 | return 0; | |
531 | } | |
532 | ||
533 | early_param("maxcpus", maxcpus); | |
534 | ||
535 | /* Setup number of possible processor ids */ | |
536 | int nr_cpu_ids __read_mostly = NR_CPUS; | |
537 | EXPORT_SYMBOL(nr_cpu_ids); | |
538 | ||
539 | /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */ | |
540 | void __init setup_nr_cpu_ids(void) | |
541 | { | |
542 | nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1; | |
543 | } | |
544 | ||
545 | void __weak smp_announce(void) | |
546 | { | |
547 | printk(KERN_INFO "Brought up %d CPUs\n", num_online_cpus()); | |
548 | } | |
549 | ||
550 | /* Called by boot processor to activate the rest. */ | |
551 | void __init smp_init(void) | |
552 | { | |
553 | unsigned int cpu; | |
554 | ||
555 | idle_threads_init(); | |
556 | cpuhp_threads_init(); | |
557 | ||
558 | /* FIXME: This should be done in userspace --RR */ | |
559 | for_each_present_cpu(cpu) { | |
560 | if (num_online_cpus() >= setup_max_cpus) | |
561 | break; | |
562 | if (!cpu_online(cpu)) | |
563 | cpu_up(cpu); | |
564 | } | |
565 | ||
566 | /* Any cleanup work */ | |
567 | smp_announce(); | |
568 | smp_cpus_done(setup_max_cpus); | |
569 | } | |
570 | ||
571 | /* | |
572 | * Call a function on all processors. May be used during early boot while | |
573 | * early_boot_irqs_disabled is set. Use local_irq_save/restore() instead | |
574 | * of local_irq_disable/enable(). | |
575 | */ | |
576 | int on_each_cpu(void (*func) (void *info), void *info, int wait) | |
577 | { | |
578 | unsigned long flags; | |
579 | int ret = 0; | |
580 | ||
581 | preempt_disable(); | |
582 | ret = smp_call_function(func, info, wait); | |
583 | local_irq_save(flags); | |
584 | func(info); | |
585 | local_irq_restore(flags); | |
586 | preempt_enable(); | |
587 | return ret; | |
588 | } | |
589 | EXPORT_SYMBOL(on_each_cpu); | |
590 | ||
591 | /** | |
592 | * on_each_cpu_mask(): Run a function on processors specified by | |
593 | * cpumask, which may include the local processor. | |
594 | * @mask: The set of cpus to run on (only runs on online subset). | |
595 | * @func: The function to run. This must be fast and non-blocking. | |
596 | * @info: An arbitrary pointer to pass to the function. | |
597 | * @wait: If true, wait (atomically) until function has completed | |
598 | * on other CPUs. | |
599 | * | |
600 | * If @wait is true, then returns once @func has returned. | |
601 | * | |
602 | * You must not call this function with disabled interrupts or from a | |
603 | * hardware interrupt handler or from a bottom half handler. The | |
604 | * exception is that it may be used during early boot while | |
605 | * early_boot_irqs_disabled is set. | |
606 | */ | |
607 | void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func, | |
608 | void *info, bool wait) | |
609 | { | |
610 | int cpu = get_cpu(); | |
611 | ||
612 | smp_call_function_many(mask, func, info, wait); | |
613 | if (cpumask_test_cpu(cpu, mask)) { | |
614 | unsigned long flags; | |
615 | local_irq_save(flags); | |
616 | func(info); | |
617 | local_irq_restore(flags); | |
618 | } | |
619 | put_cpu(); | |
620 | } | |
621 | EXPORT_SYMBOL(on_each_cpu_mask); | |
622 | ||
623 | /* | |
624 | * on_each_cpu_cond(): Call a function on each processor for which | |
625 | * the supplied function cond_func returns true, optionally waiting | |
626 | * for all the required CPUs to finish. This may include the local | |
627 | * processor. | |
628 | * @cond_func: A callback function that is passed a cpu id and | |
629 | * the the info parameter. The function is called | |
630 | * with preemption disabled. The function should | |
631 | * return a blooean value indicating whether to IPI | |
632 | * the specified CPU. | |
633 | * @func: The function to run on all applicable CPUs. | |
634 | * This must be fast and non-blocking. | |
635 | * @info: An arbitrary pointer to pass to both functions. | |
636 | * @wait: If true, wait (atomically) until function has | |
637 | * completed on other CPUs. | |
638 | * @gfp_flags: GFP flags to use when allocating the cpumask | |
639 | * used internally by the function. | |
640 | * | |
641 | * The function might sleep if the GFP flags indicates a non | |
642 | * atomic allocation is allowed. | |
643 | * | |
644 | * Preemption is disabled to protect against CPUs going offline but not online. | |
645 | * CPUs going online during the call will not be seen or sent an IPI. | |
646 | * | |
647 | * You must not call this function with disabled interrupts or | |
648 | * from a hardware interrupt handler or from a bottom half handler. | |
649 | */ | |
650 | void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info), | |
651 | smp_call_func_t func, void *info, bool wait, | |
652 | gfp_t gfp_flags) | |
653 | { | |
654 | cpumask_var_t cpus; | |
655 | int cpu, ret; | |
656 | ||
657 | might_sleep_if(gfpflags_allow_blocking(gfp_flags)); | |
658 | ||
659 | if (likely(zalloc_cpumask_var(&cpus, (gfp_flags|__GFP_NOWARN)))) { | |
660 | preempt_disable(); | |
661 | for_each_online_cpu(cpu) | |
662 | if (cond_func(cpu, info)) | |
663 | cpumask_set_cpu(cpu, cpus); | |
664 | on_each_cpu_mask(cpus, func, info, wait); | |
665 | preempt_enable(); | |
666 | free_cpumask_var(cpus); | |
667 | } else { | |
668 | /* | |
669 | * No free cpumask, bother. No matter, we'll | |
670 | * just have to IPI them one by one. | |
671 | */ | |
672 | preempt_disable(); | |
673 | for_each_online_cpu(cpu) | |
674 | if (cond_func(cpu, info)) { | |
675 | ret = smp_call_function_single(cpu, func, | |
676 | info, wait); | |
677 | WARN_ON_ONCE(ret); | |
678 | } | |
679 | preempt_enable(); | |
680 | } | |
681 | } | |
682 | EXPORT_SYMBOL(on_each_cpu_cond); | |
683 | ||
684 | static void do_nothing(void *unused) | |
685 | { | |
686 | } | |
687 | ||
688 | /** | |
689 | * kick_all_cpus_sync - Force all cpus out of idle | |
690 | * | |
691 | * Used to synchronize the update of pm_idle function pointer. It's | |
692 | * called after the pointer is updated and returns after the dummy | |
693 | * callback function has been executed on all cpus. The execution of | |
694 | * the function can only happen on the remote cpus after they have | |
695 | * left the idle function which had been called via pm_idle function | |
696 | * pointer. So it's guaranteed that nothing uses the previous pointer | |
697 | * anymore. | |
698 | */ | |
699 | void kick_all_cpus_sync(void) | |
700 | { | |
701 | /* Make sure the change is visible before we kick the cpus */ | |
702 | smp_mb(); | |
703 | smp_call_function(do_nothing, NULL, 1); | |
704 | } | |
705 | EXPORT_SYMBOL_GPL(kick_all_cpus_sync); | |
706 | ||
707 | /** | |
708 | * wake_up_all_idle_cpus - break all cpus out of idle | |
709 | * wake_up_all_idle_cpus try to break all cpus which is in idle state even | |
710 | * including idle polling cpus, for non-idle cpus, we will do nothing | |
711 | * for them. | |
712 | */ | |
713 | void wake_up_all_idle_cpus(void) | |
714 | { | |
715 | int cpu; | |
716 | ||
717 | preempt_disable(); | |
718 | for_each_online_cpu(cpu) { | |
719 | if (cpu == smp_processor_id()) | |
720 | continue; | |
721 | ||
722 | wake_up_if_idle(cpu); | |
723 | } | |
724 | preempt_enable(); | |
725 | } | |
726 | EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus); |