smp.c 20.0 KB
Newer Older
1 2 3 4 5
/*
 * Generic helpers for smp ipi calls
 *
 * (C) Jens Axboe <jens.axboe@oracle.com> 2008
 */
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>
I
Ingo Molnar 已提交
11 12
#include <linux/percpu.h>
#include <linux/init.h>
13
#include <linux/gfp.h>
14
#include <linux/smp.h>
P
Peter Zijlstra 已提交
15
#include <linux/cpu.h>
16
#include <linux/sched.h>
17

18 19
#include "smpboot.h"

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;
I
Ingo Molnar 已提交
27
	cpumask_var_t		cpumask;
28 29
};

30 31
static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_function_data, cfd_data);

32
static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head, call_single_queue);
P
Peter Zijlstra 已提交
33

34 35
static void flush_smp_call_function_queue(bool warn_cpu_offline);

P
Peter Zijlstra 已提交
36 37 38 39 40 41 42 43 44
static int
hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu)
{
	long cpu = (long)hcpu;
	struct call_function_data *cfd = &per_cpu(cfd_data, cpu);

	switch (action) {
	case CPU_UP_PREPARE:
	case CPU_UP_PREPARE_FROZEN:
45
		if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL,
P
Peter Zijlstra 已提交
46
				cpu_to_node(cpu)))
47
			return notifier_from_errno(-ENOMEM);
48 49 50 51 52
		cfd->csd = alloc_percpu(struct call_single_data);
		if (!cfd->csd) {
			free_cpumask_var(cfd->cpumask);
			return notifier_from_errno(-ENOMEM);
		}
P
Peter Zijlstra 已提交
53 54
		break;

X
Xiao Guangrong 已提交
55
#ifdef CONFIG_HOTPLUG_CPU
P
Peter Zijlstra 已提交
56 57
	case CPU_UP_CANCELED:
	case CPU_UP_CANCELED_FROZEN:
58
		/* Fall-through to the CPU_DEAD[_FROZEN] case. */
P
Peter Zijlstra 已提交
59 60 61 62

	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		free_cpumask_var(cfd->cpumask);
63
		free_percpu(cfd->csd);
P
Peter Zijlstra 已提交
64
		break;
65 66 67 68 69 70 71 72 73 74 75 76 77 78

	case CPU_DYING:
	case CPU_DYING_FROZEN:
		/*
		 * The IPIs for the smp-call-function callbacks queued by other
		 * CPUs might arrive late, either due to hardware latencies or
		 * because this CPU disabled interrupts (inside stop-machine)
		 * before the IPIs were sent. So flush out any pending callbacks
		 * explicitly (without waiting for the IPIs to arrive), to
		 * ensure that the outgoing CPU doesn't go offline with work
		 * still pending.
		 */
		flush_smp_call_function_queue(false);
		break;
P
Peter Zijlstra 已提交
79 80 81 82 83 84
#endif
	};

	return NOTIFY_OK;
}

85
static struct notifier_block hotplug_cfd_notifier = {
I
Ingo Molnar 已提交
86
	.notifier_call		= hotplug_cfd,
P
Peter Zijlstra 已提交
87 88
};

89
void __init call_function_init(void)
90
{
P
Peter Zijlstra 已提交
91
	void *cpu = (void *)(long)smp_processor_id();
92 93
	int i;

94 95
	for_each_possible_cpu(i)
		init_llist_head(&per_cpu(call_single_queue, i));
P
Peter Zijlstra 已提交
96 97 98

	hotplug_cfd(&hotplug_cfd_notifier, CPU_UP_PREPARE, cpu);
	register_cpu_notifier(&hotplug_cfd_notifier);
99 100
}

P
Peter Zijlstra 已提交
101 102 103
/*
 * csd_lock/csd_unlock used to serialize access to per-cpu csd resources
 *
I
Ingo Molnar 已提交
104 105 106
 * For non-synchronous ipi calls the csd can still be in use by the
 * previous function call. For multi-cpu calls its even more interesting
 * as we'll have to ensure no other cpu is observing our csd.
P
Peter Zijlstra 已提交
107
 */
108
static __always_inline void csd_lock_wait(struct call_single_data *csd)
P
Peter Zijlstra 已提交
109
{
110
	smp_cond_load_acquire(&csd->flags, !(VAL & CSD_FLAG_LOCK));
111 112
}

113
static __always_inline void csd_lock(struct call_single_data *csd)
114
{
A
Andrew Morton 已提交
115 116
	csd_lock_wait(csd);
	csd->flags |= CSD_FLAG_LOCK;
P
Peter Zijlstra 已提交
117 118

	/*
I
Ingo Molnar 已提交
119 120 121
	 * prevent CPU from reordering the above assignment
	 * to ->flags with any subsequent assignments to other
	 * fields of the specified call_single_data structure:
P
Peter Zijlstra 已提交
122
	 */
123
	smp_wmb();
P
Peter Zijlstra 已提交
124 125
}

126
static __always_inline void csd_unlock(struct call_single_data *csd)
P
Peter Zijlstra 已提交
127
{
128
	WARN_ON(!(csd->flags & CSD_FLAG_LOCK));
I
Ingo Molnar 已提交
129

P
Peter Zijlstra 已提交
130
	/*
I
Ingo Molnar 已提交
131
	 * ensure we're all done before releasing data:
P
Peter Zijlstra 已提交
132
	 */
133
	smp_store_release(&csd->flags, 0);
134 135
}

136 137
static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data);

138
/*
I
Ingo Molnar 已提交
139 140 141
 * Insert a previously allocated call_single_data element
 * for execution on the given CPU. data must already have
 * ->func, ->info, and ->flags set.
142
 */
143
static int generic_exec_single(int cpu, struct call_single_data *csd,
144
			       smp_call_func_t func, void *info)
145
{
146
	if (cpu == smp_processor_id()) {
147 148 149 150 151 152 153
		unsigned long flags;

		/*
		 * We can unlock early even for the synchronous on-stack case,
		 * since we're doing this from the same CPU..
		 */
		csd_unlock(csd);
154 155 156 157 158 159 160
		local_irq_save(flags);
		func(info);
		local_irq_restore(flags);
		return 0;
	}


161 162
	if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu)) {
		csd_unlock(csd);
163
		return -ENXIO;
164
	}
165 166 167 168

	csd->func = func;
	csd->info = info;

169
	/*
170 171 172 173 174 175 176
	 * The list addition should be visible before sending the IPI
	 * handler locks the list to pull the entry off it because of
	 * normal cache coherency rules implied by spinlocks.
	 *
	 * If IPIs can go out of order to the cache coherency protocol
	 * in an architecture, sufficient synchronisation should be added
	 * to arch code to make it appear to obey cache coherency WRT
I
Ingo Molnar 已提交
177 178
	 * locking and barrier primitives. Generic code isn't really
	 * equipped to do the right thing...
179
	 */
180
	if (llist_add(&csd->llist, &per_cpu(call_single_queue, cpu)))
181 182
		arch_send_call_function_single_ipi(cpu);

183
	return 0;
184 185
}

186 187 188 189 190
/**
 * generic_smp_call_function_single_interrupt - Execute SMP IPI callbacks
 *
 * Invoked by arch to handle an IPI for call function single.
 * Must be called with interrupts disabled.
191 192 193
 */
void generic_smp_call_function_single_interrupt(void)
{
194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213
	flush_smp_call_function_queue(true);
}

/**
 * flush_smp_call_function_queue - Flush pending smp-call-function callbacks
 *
 * @warn_cpu_offline: If set to 'true', warn if callbacks were queued on an
 *		      offline CPU. Skip this check if set to 'false'.
 *
 * Flush any pending smp-call-function callbacks queued on this CPU. This is
 * invoked by the generic IPI handler, as well as by a CPU about to go offline,
 * to ensure that all pending IPI callbacks are run before it goes completely
 * offline.
 *
 * Loop through the call_single_queue and run all the queued callbacks.
 * Must be called with interrupts disabled.
 */
static void flush_smp_call_function_queue(bool warn_cpu_offline)
{
	struct llist_head *head;
214 215
	struct llist_node *entry;
	struct call_single_data *csd, *csd_next;
216 217
	static bool warned;

218 219
	WARN_ON(!irqs_disabled());

220
	head = this_cpu_ptr(&call_single_queue);
221
	entry = llist_del_all(head);
222
	entry = llist_reverse_order(entry);
223

224 225 226
	/* There shouldn't be any pending callbacks on an offline CPU. */
	if (unlikely(warn_cpu_offline && !cpu_online(smp_processor_id()) &&
		     !warned && !llist_empty(head))) {
227 228 229 230 231 232 233 234 235 236 237
		warned = true;
		WARN(1, "IPI on offline CPU %d\n", smp_processor_id());

		/*
		 * We don't have to use the _safe() variant here
		 * because we are not invoking the IPI handlers yet.
		 */
		llist_for_each_entry(csd, entry, llist)
			pr_warn("IPI callback %pS sent to offline CPU\n",
				csd->func);
	}
238

239
	llist_for_each_entry_safe(csd, csd_next, entry, llist) {
240 241 242 243 244 245 246 247 248 249 250
		smp_call_func_t func = csd->func;
		void *info = csd->info;

		/* Do we wait until *after* callback? */
		if (csd->flags & CSD_FLAG_SYNCHRONOUS) {
			func(info);
			csd_unlock(csd);
		} else {
			csd_unlock(csd);
			func(info);
		}
251
	}
252 253 254 255 256 257 258 259

	/*
	 * Handle irq works queued remotely by irq_work_queue_on().
	 * Smp functions above are typically synchronous so they
	 * better run first since some other CPUs may be busy waiting
	 * for them.
	 */
	irq_work_run();
260 261 262 263 264 265 266 267
}

/*
 * smp_call_function_single - Run a function on a specific CPU
 * @func: The function to run. This must be fast and non-blocking.
 * @info: An arbitrary pointer to pass to the function.
 * @wait: If true, wait until function has completed on other CPUs.
 *
268
 * Returns 0 on success, else a negative status code.
269
 */
D
David Howells 已提交
270
int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
271
			     int wait)
272
{
273 274
	struct call_single_data *csd;
	struct call_single_data csd_stack = { .flags = CSD_FLAG_LOCK | CSD_FLAG_SYNCHRONOUS };
I
Ingo Molnar 已提交
275
	int this_cpu;
276
	int err;
277

I
Ingo Molnar 已提交
278 279 280 281 282 283
	/*
	 * prevent preemption and reschedule on another processor,
	 * as well as CPU removal
	 */
	this_cpu = get_cpu();

284 285 286 287 288 289 290 291
	/*
	 * Can deadlock when called with interrupts disabled.
	 * We allow cpu's that are not yet online though, as no one else can
	 * send smp call function interrupt to this cpu and as such deadlocks
	 * can't happen.
	 */
	WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
		     && !oops_in_progress);
292

293 294 295 296 297 298 299 300 301 302
	csd = &csd_stack;
	if (!wait) {
		csd = this_cpu_ptr(&csd_data);
		csd_lock(csd);
	}

	err = generic_exec_single(cpu, csd, func, info);

	if (wait)
		csd_lock_wait(csd);
303 304

	put_cpu();
I
Ingo Molnar 已提交
305

306
	return err;
307 308 309
}
EXPORT_SYMBOL(smp_call_function_single);

310
/**
311 312
 * smp_call_function_single_async(): Run an asynchronous function on a
 * 			         specific CPU.
313 314 315
 * @cpu: The CPU to run on.
 * @csd: Pre-allocated and setup data structure
 *
316 317 318 319 320 321 322 323 324
 * Like smp_call_function_single(), but the call is asynchonous and
 * can thus be done from contexts with disabled interrupts.
 *
 * The caller passes his own pre-allocated data structure
 * (ie: embedded in an object) and is responsible for synchronizing it
 * such that the IPIs performed on the @csd are strictly serialized.
 *
 * NOTE: Be careful, there is unfortunately no current debugging facility to
 * validate the correctness of this serialization.
325
 */
326
int smp_call_function_single_async(int cpu, struct call_single_data *csd)
327 328 329
{
	int err = 0;

330
	preempt_disable();
331 332 333 334 335 336 337 338 339

	/* We could deadlock if we have to wait here with interrupts disabled! */
	if (WARN_ON_ONCE(csd->flags & CSD_FLAG_LOCK))
		csd_lock_wait(csd);

	csd->flags = CSD_FLAG_LOCK;
	smp_wmb();

	err = generic_exec_single(cpu, csd, csd->func, csd->info);
340
	preempt_enable();
341 342 343

	return err;
}
344
EXPORT_SYMBOL_GPL(smp_call_function_single_async);
345

346 347 348 349 350 351 352 353 354 355 356 357 358 359 360
/*
 * smp_call_function_any - Run a function on any of the given cpus
 * @mask: The mask of cpus it can run on.
 * @func: The function to run. This must be fast and non-blocking.
 * @info: An arbitrary pointer to pass to the function.
 * @wait: If true, wait until function has completed.
 *
 * Returns 0 on success, else a negative status code (if no cpus were online).
 *
 * Selection preference:
 *	1) current cpu if in @mask
 *	2) any cpu of current node if in @mask
 *	3) any other online cpu in @mask
 */
int smp_call_function_any(const struct cpumask *mask,
D
David Howells 已提交
361
			  smp_call_func_t func, void *info, int wait)
362 363 364 365 366 367 368 369 370 371 372
{
	unsigned int cpu;
	const struct cpumask *nodemask;
	int ret;

	/* Try for same CPU (cheapest) */
	cpu = get_cpu();
	if (cpumask_test_cpu(cpu, mask))
		goto call;

	/* Try for same node. */
373
	nodemask = cpumask_of_node(cpu_to_node(cpu));
374 375 376 377 378 379 380 381 382 383 384 385 386 387 388
	for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids;
	     cpu = cpumask_next_and(cpu, nodemask, mask)) {
		if (cpu_online(cpu))
			goto call;
	}

	/* Any online will do: smp_call_function_single handles nr_cpu_ids. */
	cpu = cpumask_any_and(mask, cpu_online_mask);
call:
	ret = smp_call_function_single(cpu, func, info, wait);
	put_cpu();
	return ret;
}
EXPORT_SYMBOL_GPL(smp_call_function_any);

389
/**
R
Rusty Russell 已提交
390 391
 * smp_call_function_many(): Run a function on a set of other CPUs.
 * @mask: The set of cpus to run on (only runs on online subset).
392 393
 * @func: The function to run. This must be fast and non-blocking.
 * @info: An arbitrary pointer to pass to the function.
I
Ingo Molnar 已提交
394 395
 * @wait: If true, wait (atomically) until function has completed
 *        on other CPUs.
396
 *
397
 * If @wait is true, then returns once @func has returned.
398 399 400 401 402
 *
 * You must not call this function with disabled interrupts or from a
 * hardware interrupt handler or from a bottom half handler. Preemption
 * must be disabled when calling this function.
 */
R
Rusty Russell 已提交
403
void smp_call_function_many(const struct cpumask *mask,
D
David Howells 已提交
404
			    smp_call_func_t func, void *info, bool wait)
405
{
A
Andrew Morton 已提交
406
	struct call_function_data *cfd;
407
	int cpu, next_cpu, this_cpu = smp_processor_id();
408

409 410 411 412 413 414 415
	/*
	 * Can deadlock when called with interrupts disabled.
	 * We allow cpu's that are not yet online though, as no one else can
	 * send smp call function interrupt to this cpu and as such deadlocks
	 * can't happen.
	 */
	WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
416
		     && !oops_in_progress && !early_boot_irqs_disabled);
417

418
	/* Try to fastpath.  So, what's a CPU they want? Ignoring this one. */
R
Rusty Russell 已提交
419
	cpu = cpumask_first_and(mask, cpu_online_mask);
I
Ingo Molnar 已提交
420
	if (cpu == this_cpu)
R
Rusty Russell 已提交
421
		cpu = cpumask_next_and(cpu, mask, cpu_online_mask);
I
Ingo Molnar 已提交
422

R
Rusty Russell 已提交
423 424 425 426 427 428
	/* No online cpus?  We're done. */
	if (cpu >= nr_cpu_ids)
		return;

	/* Do we have another CPU which isn't us? */
	next_cpu = cpumask_next_and(cpu, mask, cpu_online_mask);
I
Ingo Molnar 已提交
429
	if (next_cpu == this_cpu)
R
Rusty Russell 已提交
430 431 432 433 434 435
		next_cpu = cpumask_next_and(next_cpu, mask, cpu_online_mask);

	/* Fastpath: do that cpu by itself. */
	if (next_cpu >= nr_cpu_ids) {
		smp_call_function_single(cpu, func, info, wait);
		return;
436 437
	}

438
	cfd = this_cpu_ptr(&cfd_data);
439

A
Andrew Morton 已提交
440 441
	cpumask_and(cfd->cpumask, mask, cpu_online_mask);
	cpumask_clear_cpu(this_cpu, cfd->cpumask);
442 443

	/* Some callers race with other cpus changing the passed mask */
A
Andrew Morton 已提交
444
	if (unlikely(!cpumask_weight(cfd->cpumask)))
445
		return;
446

A
Andrew Morton 已提交
447 448
	for_each_cpu(cpu, cfd->cpumask) {
		struct call_single_data *csd = per_cpu_ptr(cfd->csd, cpu);
449 450

		csd_lock(csd);
451 452
		if (wait)
			csd->flags |= CSD_FLAG_SYNCHRONOUS;
453 454
		csd->func = func;
		csd->info = info;
455
		llist_add(&csd->llist, &per_cpu(call_single_queue, cpu));
456
	}
457

458
	/* Send a message to all CPUs in the map */
459
	arch_send_call_function_ipi_mask(cfd->cpumask);
460

461
	if (wait) {
A
Andrew Morton 已提交
462 463 464 465
		for_each_cpu(cpu, cfd->cpumask) {
			struct call_single_data *csd;

			csd = per_cpu_ptr(cfd->csd, cpu);
466 467 468
			csd_lock_wait(csd);
		}
	}
469
}
R
Rusty Russell 已提交
470
EXPORT_SYMBOL(smp_call_function_many);
471 472 473 474 475

/**
 * smp_call_function(): Run a function on all other CPUs.
 * @func: The function to run. This must be fast and non-blocking.
 * @info: An arbitrary pointer to pass to the function.
I
Ingo Molnar 已提交
476 477
 * @wait: If true, wait (atomically) until function has completed
 *        on other CPUs.
478
 *
R
Rusty Russell 已提交
479
 * Returns 0.
480 481
 *
 * If @wait is true, then returns once @func has returned; otherwise
482
 * it returns just before the target cpu calls @func.
483 484 485 486
 *
 * You must not call this function with disabled interrupts or from a
 * hardware interrupt handler or from a bottom half handler.
 */
D
David Howells 已提交
487
int smp_call_function(smp_call_func_t func, void *info, int wait)
488 489
{
	preempt_disable();
R
Rusty Russell 已提交
490
	smp_call_function_many(cpu_online_mask, func, info, wait);
491
	preempt_enable();
I
Ingo Molnar 已提交
492

R
Rusty Russell 已提交
493
	return 0;
494 495
}
EXPORT_SYMBOL(smp_call_function);
496

497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559
/* Setup configured maximum number of CPUs to activate */
unsigned int setup_max_cpus = NR_CPUS;
EXPORT_SYMBOL(setup_max_cpus);


/*
 * Setup routine for controlling SMP activation
 *
 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
 * activation entirely (the MPS table probe still happens, though).
 *
 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
 * greater than 0, limits the maximum number of CPUs activated in
 * SMP mode to <NUM>.
 */

void __weak arch_disable_smp_support(void) { }

static int __init nosmp(char *str)
{
	setup_max_cpus = 0;
	arch_disable_smp_support();

	return 0;
}

early_param("nosmp", nosmp);

/* this is hard limit */
static int __init nrcpus(char *str)
{
	int nr_cpus;

	get_option(&str, &nr_cpus);
	if (nr_cpus > 0 && nr_cpus < nr_cpu_ids)
		nr_cpu_ids = nr_cpus;

	return 0;
}

early_param("nr_cpus", nrcpus);

static int __init maxcpus(char *str)
{
	get_option(&str, &setup_max_cpus);
	if (setup_max_cpus == 0)
		arch_disable_smp_support();

	return 0;
}

early_param("maxcpus", maxcpus);

/* Setup number of possible processor ids */
int nr_cpu_ids __read_mostly = NR_CPUS;
EXPORT_SYMBOL(nr_cpu_ids);

/* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
void __init setup_nr_cpu_ids(void)
{
	nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
}

560 561 562 563 564
void __weak smp_announce(void)
{
	printk(KERN_INFO "Brought up %d CPUs\n", num_online_cpus());
}

565 566 567 568 569
/* Called by boot processor to activate the rest. */
void __init smp_init(void)
{
	unsigned int cpu;

570
	idle_threads_init();
571
	cpuhp_threads_init();
572

573 574 575 576 577 578 579 580 581
	/* FIXME: This should be done in userspace --RR */
	for_each_present_cpu(cpu) {
		if (num_online_cpus() >= setup_max_cpus)
			break;
		if (!cpu_online(cpu))
			cpu_up(cpu);
	}

	/* Any cleanup work */
582
	smp_announce();
583 584 585
	smp_cpus_done(setup_max_cpus);
}

586
/*
587 588 589
 * Call a function on all processors.  May be used during early boot while
 * early_boot_irqs_disabled is set.  Use local_irq_save/restore() instead
 * of local_irq_disable/enable().
590 591 592
 */
int on_each_cpu(void (*func) (void *info), void *info, int wait)
{
593
	unsigned long flags;
594 595 596 597
	int ret = 0;

	preempt_disable();
	ret = smp_call_function(func, info, wait);
598
	local_irq_save(flags);
599
	func(info);
600
	local_irq_restore(flags);
601 602 603 604
	preempt_enable();
	return ret;
}
EXPORT_SYMBOL(on_each_cpu);
605 606 607 608 609 610 611 612 613 614 615 616

/**
 * on_each_cpu_mask(): Run a function on processors specified by
 * cpumask, which may include the local processor.
 * @mask: The set of cpus to run on (only runs on online subset).
 * @func: The function to run. This must be fast and non-blocking.
 * @info: An arbitrary pointer to pass to the function.
 * @wait: If true, wait (atomically) until function has completed
 *        on other CPUs.
 *
 * If @wait is true, then returns once @func has returned.
 *
617 618 619 620
 * You must not call this function with disabled interrupts or from a
 * hardware interrupt handler or from a bottom half handler.  The
 * exception is that it may be used during early boot while
 * early_boot_irqs_disabled is set.
621 622 623 624 625 626 627 628
 */
void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
			void *info, bool wait)
{
	int cpu = get_cpu();

	smp_call_function_many(mask, func, info, wait);
	if (cpumask_test_cpu(cpu, mask)) {
629 630
		unsigned long flags;
		local_irq_save(flags);
631
		func(info);
632
		local_irq_restore(flags);
633 634 635 636
	}
	put_cpu();
}
EXPORT_SYMBOL(on_each_cpu_mask);
637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671

/*
 * on_each_cpu_cond(): Call a function on each processor for which
 * the supplied function cond_func returns true, optionally waiting
 * for all the required CPUs to finish. This may include the local
 * processor.
 * @cond_func:	A callback function that is passed a cpu id and
 *		the the info parameter. The function is called
 *		with preemption disabled. The function should
 *		return a blooean value indicating whether to IPI
 *		the specified CPU.
 * @func:	The function to run on all applicable CPUs.
 *		This must be fast and non-blocking.
 * @info:	An arbitrary pointer to pass to both functions.
 * @wait:	If true, wait (atomically) until function has
 *		completed on other CPUs.
 * @gfp_flags:	GFP flags to use when allocating the cpumask
 *		used internally by the function.
 *
 * The function might sleep if the GFP flags indicates a non
 * atomic allocation is allowed.
 *
 * Preemption is disabled to protect against CPUs going offline but not online.
 * CPUs going online during the call will not be seen or sent an IPI.
 *
 * You must not call this function with disabled interrupts or
 * from a hardware interrupt handler or from a bottom half handler.
 */
void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
			smp_call_func_t func, void *info, bool wait,
			gfp_t gfp_flags)
{
	cpumask_var_t cpus;
	int cpu, ret;

672
	might_sleep_if(gfpflags_allow_blocking(gfp_flags));
673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691

	if (likely(zalloc_cpumask_var(&cpus, (gfp_flags|__GFP_NOWARN)))) {
		preempt_disable();
		for_each_online_cpu(cpu)
			if (cond_func(cpu, info))
				cpumask_set_cpu(cpu, cpus);
		on_each_cpu_mask(cpus, func, info, wait);
		preempt_enable();
		free_cpumask_var(cpus);
	} else {
		/*
		 * No free cpumask, bother. No matter, we'll
		 * just have to IPI them one by one.
		 */
		preempt_disable();
		for_each_online_cpu(cpu)
			if (cond_func(cpu, info)) {
				ret = smp_call_function_single(cpu, func,
								info, wait);
692
				WARN_ON_ONCE(ret);
693 694 695 696 697
			}
		preempt_enable();
	}
}
EXPORT_SYMBOL(on_each_cpu_cond);
698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720

static void do_nothing(void *unused)
{
}

/**
 * kick_all_cpus_sync - Force all cpus out of idle
 *
 * Used to synchronize the update of pm_idle function pointer. It's
 * called after the pointer is updated and returns after the dummy
 * callback function has been executed on all cpus. The execution of
 * the function can only happen on the remote cpus after they have
 * left the idle function which had been called via pm_idle function
 * pointer. So it's guaranteed that nothing uses the previous pointer
 * anymore.
 */
void kick_all_cpus_sync(void)
{
	/* Make sure the change is visible before we kick the cpus */
	smp_mb();
	smp_call_function(do_nothing, NULL, 1);
}
EXPORT_SYMBOL_GPL(kick_all_cpus_sync);
721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741

/**
 * wake_up_all_idle_cpus - break all cpus out of idle
 * wake_up_all_idle_cpus try to break all cpus which is in idle state even
 * including idle polling cpus, for non-idle cpus, we will do nothing
 * for them.
 */
void wake_up_all_idle_cpus(void)
{
	int cpu;

	preempt_disable();
	for_each_online_cpu(cpu) {
		if (cpu == smp_processor_id())
			continue;

		wake_up_if_idle(cpu);
	}
	preempt_enable();
}
EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus);