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