Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/softirq.c | |
3 | * | |
4 | * Copyright (C) 1992 Linus Torvalds | |
5 | * | |
6 | * Rewritten. Old one was good in 2.2, but in 2.3 it was immoral. --ANK (990903) | |
7 | */ | |
8 | ||
9 | #include <linux/module.h> | |
10 | #include <linux/kernel_stat.h> | |
11 | #include <linux/interrupt.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/mm.h> | |
14 | #include <linux/notifier.h> | |
15 | #include <linux/percpu.h> | |
16 | #include <linux/cpu.h> | |
83144186 | 17 | #include <linux/freezer.h> |
1da177e4 LT |
18 | #include <linux/kthread.h> |
19 | #include <linux/rcupdate.h> | |
78eef01b | 20 | #include <linux/smp.h> |
79bf2bb3 | 21 | #include <linux/tick.h> |
1da177e4 LT |
22 | |
23 | #include <asm/irq.h> | |
24 | /* | |
25 | - No shared variables, all the data are CPU local. | |
26 | - If a softirq needs serialization, let it serialize itself | |
27 | by its own spinlocks. | |
28 | - Even if softirq is serialized, only local cpu is marked for | |
29 | execution. Hence, we get something sort of weak cpu binding. | |
30 | Though it is still not clear, will it result in better locality | |
31 | or will not. | |
32 | ||
33 | Examples: | |
34 | - NET RX softirq. It is multithreaded and does not require | |
35 | any global serialization. | |
36 | - NET TX softirq. It kicks software netdevice queues, hence | |
37 | it is logically serialized per device, but this serialization | |
38 | is invisible to common code. | |
39 | - Tasklets: serialized wrt itself. | |
40 | */ | |
41 | ||
42 | #ifndef __ARCH_IRQ_STAT | |
43 | irq_cpustat_t irq_stat[NR_CPUS] ____cacheline_aligned; | |
44 | EXPORT_SYMBOL(irq_stat); | |
45 | #endif | |
46 | ||
47 | static struct softirq_action softirq_vec[32] __cacheline_aligned_in_smp; | |
48 | ||
49 | static DEFINE_PER_CPU(struct task_struct *, ksoftirqd); | |
50 | ||
51 | /* | |
52 | * we cannot loop indefinitely here to avoid userspace starvation, | |
53 | * but we also don't want to introduce a worst case 1/HZ latency | |
54 | * to the pending events, so lets the scheduler to balance | |
55 | * the softirq load for us. | |
56 | */ | |
57 | static inline void wakeup_softirqd(void) | |
58 | { | |
59 | /* Interrupts are disabled: no need to stop preemption */ | |
60 | struct task_struct *tsk = __get_cpu_var(ksoftirqd); | |
61 | ||
62 | if (tsk && tsk->state != TASK_RUNNING) | |
63 | wake_up_process(tsk); | |
64 | } | |
65 | ||
de30a2b3 IM |
66 | /* |
67 | * This one is for softirq.c-internal use, | |
68 | * where hardirqs are disabled legitimately: | |
69 | */ | |
3c829c36 | 70 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 IM |
71 | static void __local_bh_disable(unsigned long ip) |
72 | { | |
73 | unsigned long flags; | |
74 | ||
75 | WARN_ON_ONCE(in_irq()); | |
76 | ||
77 | raw_local_irq_save(flags); | |
78 | add_preempt_count(SOFTIRQ_OFFSET); | |
79 | /* | |
80 | * Were softirqs turned off above: | |
81 | */ | |
82 | if (softirq_count() == SOFTIRQ_OFFSET) | |
83 | trace_softirqs_off(ip); | |
84 | raw_local_irq_restore(flags); | |
85 | } | |
3c829c36 TC |
86 | #else /* !CONFIG_TRACE_IRQFLAGS */ |
87 | static inline void __local_bh_disable(unsigned long ip) | |
88 | { | |
89 | add_preempt_count(SOFTIRQ_OFFSET); | |
90 | barrier(); | |
91 | } | |
92 | #endif /* CONFIG_TRACE_IRQFLAGS */ | |
de30a2b3 IM |
93 | |
94 | void local_bh_disable(void) | |
95 | { | |
96 | __local_bh_disable((unsigned long)__builtin_return_address(0)); | |
97 | } | |
98 | ||
99 | EXPORT_SYMBOL(local_bh_disable); | |
100 | ||
101 | void __local_bh_enable(void) | |
102 | { | |
103 | WARN_ON_ONCE(in_irq()); | |
104 | ||
105 | /* | |
106 | * softirqs should never be enabled by __local_bh_enable(), | |
107 | * it always nests inside local_bh_enable() sections: | |
108 | */ | |
109 | WARN_ON_ONCE(softirq_count() == SOFTIRQ_OFFSET); | |
110 | ||
111 | sub_preempt_count(SOFTIRQ_OFFSET); | |
112 | } | |
113 | EXPORT_SYMBOL_GPL(__local_bh_enable); | |
114 | ||
115 | /* | |
116 | * Special-case - softirqs can safely be enabled in | |
117 | * cond_resched_softirq(), or by __do_softirq(), | |
118 | * without processing still-pending softirqs: | |
119 | */ | |
120 | void _local_bh_enable(void) | |
121 | { | |
122 | WARN_ON_ONCE(in_irq()); | |
123 | WARN_ON_ONCE(!irqs_disabled()); | |
124 | ||
125 | if (softirq_count() == SOFTIRQ_OFFSET) | |
126 | trace_softirqs_on((unsigned long)__builtin_return_address(0)); | |
127 | sub_preempt_count(SOFTIRQ_OFFSET); | |
128 | } | |
129 | ||
130 | EXPORT_SYMBOL(_local_bh_enable); | |
131 | ||
132 | void local_bh_enable(void) | |
133 | { | |
3c829c36 | 134 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 IM |
135 | unsigned long flags; |
136 | ||
137 | WARN_ON_ONCE(in_irq()); | |
3c829c36 | 138 | #endif |
de30a2b3 IM |
139 | WARN_ON_ONCE(irqs_disabled()); |
140 | ||
3c829c36 | 141 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 | 142 | local_irq_save(flags); |
3c829c36 | 143 | #endif |
de30a2b3 IM |
144 | /* |
145 | * Are softirqs going to be turned on now: | |
146 | */ | |
147 | if (softirq_count() == SOFTIRQ_OFFSET) | |
148 | trace_softirqs_on((unsigned long)__builtin_return_address(0)); | |
149 | /* | |
150 | * Keep preemption disabled until we are done with | |
151 | * softirq processing: | |
152 | */ | |
153 | sub_preempt_count(SOFTIRQ_OFFSET - 1); | |
154 | ||
155 | if (unlikely(!in_interrupt() && local_softirq_pending())) | |
156 | do_softirq(); | |
157 | ||
158 | dec_preempt_count(); | |
3c829c36 | 159 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 | 160 | local_irq_restore(flags); |
3c829c36 | 161 | #endif |
de30a2b3 IM |
162 | preempt_check_resched(); |
163 | } | |
164 | EXPORT_SYMBOL(local_bh_enable); | |
165 | ||
166 | void local_bh_enable_ip(unsigned long ip) | |
167 | { | |
3c829c36 | 168 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 IM |
169 | unsigned long flags; |
170 | ||
171 | WARN_ON_ONCE(in_irq()); | |
172 | ||
173 | local_irq_save(flags); | |
3c829c36 | 174 | #endif |
de30a2b3 IM |
175 | /* |
176 | * Are softirqs going to be turned on now: | |
177 | */ | |
178 | if (softirq_count() == SOFTIRQ_OFFSET) | |
179 | trace_softirqs_on(ip); | |
180 | /* | |
181 | * Keep preemption disabled until we are done with | |
182 | * softirq processing: | |
183 | */ | |
184 | sub_preempt_count(SOFTIRQ_OFFSET - 1); | |
185 | ||
186 | if (unlikely(!in_interrupt() && local_softirq_pending())) | |
187 | do_softirq(); | |
188 | ||
189 | dec_preempt_count(); | |
3c829c36 | 190 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 | 191 | local_irq_restore(flags); |
3c829c36 | 192 | #endif |
de30a2b3 IM |
193 | preempt_check_resched(); |
194 | } | |
195 | EXPORT_SYMBOL(local_bh_enable_ip); | |
196 | ||
1da177e4 LT |
197 | /* |
198 | * We restart softirq processing MAX_SOFTIRQ_RESTART times, | |
199 | * and we fall back to softirqd after that. | |
200 | * | |
201 | * This number has been established via experimentation. | |
202 | * The two things to balance is latency against fairness - | |
203 | * we want to handle softirqs as soon as possible, but they | |
204 | * should not be able to lock up the box. | |
205 | */ | |
206 | #define MAX_SOFTIRQ_RESTART 10 | |
207 | ||
208 | asmlinkage void __do_softirq(void) | |
209 | { | |
210 | struct softirq_action *h; | |
211 | __u32 pending; | |
212 | int max_restart = MAX_SOFTIRQ_RESTART; | |
213 | int cpu; | |
214 | ||
215 | pending = local_softirq_pending(); | |
829035fd PM |
216 | account_system_vtime(current); |
217 | ||
de30a2b3 IM |
218 | __local_bh_disable((unsigned long)__builtin_return_address(0)); |
219 | trace_softirq_enter(); | |
1da177e4 | 220 | |
1da177e4 LT |
221 | cpu = smp_processor_id(); |
222 | restart: | |
223 | /* Reset the pending bitmask before enabling irqs */ | |
3f74478b | 224 | set_softirq_pending(0); |
1da177e4 | 225 | |
c70f5d66 | 226 | local_irq_enable(); |
1da177e4 LT |
227 | |
228 | h = softirq_vec; | |
229 | ||
230 | do { | |
231 | if (pending & 1) { | |
232 | h->action(h); | |
233 | rcu_bh_qsctr_inc(cpu); | |
234 | } | |
235 | h++; | |
236 | pending >>= 1; | |
237 | } while (pending); | |
238 | ||
c70f5d66 | 239 | local_irq_disable(); |
1da177e4 LT |
240 | |
241 | pending = local_softirq_pending(); | |
242 | if (pending && --max_restart) | |
243 | goto restart; | |
244 | ||
245 | if (pending) | |
246 | wakeup_softirqd(); | |
247 | ||
de30a2b3 | 248 | trace_softirq_exit(); |
829035fd PM |
249 | |
250 | account_system_vtime(current); | |
de30a2b3 | 251 | _local_bh_enable(); |
1da177e4 LT |
252 | } |
253 | ||
254 | #ifndef __ARCH_HAS_DO_SOFTIRQ | |
255 | ||
256 | asmlinkage void do_softirq(void) | |
257 | { | |
258 | __u32 pending; | |
259 | unsigned long flags; | |
260 | ||
261 | if (in_interrupt()) | |
262 | return; | |
263 | ||
264 | local_irq_save(flags); | |
265 | ||
266 | pending = local_softirq_pending(); | |
267 | ||
268 | if (pending) | |
269 | __do_softirq(); | |
270 | ||
271 | local_irq_restore(flags); | |
272 | } | |
273 | ||
1da177e4 LT |
274 | #endif |
275 | ||
dde4b2b5 IM |
276 | /* |
277 | * Enter an interrupt context. | |
278 | */ | |
279 | void irq_enter(void) | |
280 | { | |
79bf2bb3 TG |
281 | __irq_enter(); |
282 | #ifdef CONFIG_NO_HZ | |
283 | if (idle_cpu(smp_processor_id())) | |
284 | tick_nohz_update_jiffies(); | |
285 | #endif | |
dde4b2b5 IM |
286 | } |
287 | ||
1da177e4 LT |
288 | #ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED |
289 | # define invoke_softirq() __do_softirq() | |
290 | #else | |
291 | # define invoke_softirq() do_softirq() | |
292 | #endif | |
293 | ||
294 | /* | |
295 | * Exit an interrupt context. Process softirqs if needed and possible: | |
296 | */ | |
297 | void irq_exit(void) | |
298 | { | |
299 | account_system_vtime(current); | |
de30a2b3 | 300 | trace_hardirq_exit(); |
1da177e4 LT |
301 | sub_preempt_count(IRQ_EXIT_OFFSET); |
302 | if (!in_interrupt() && local_softirq_pending()) | |
303 | invoke_softirq(); | |
79bf2bb3 TG |
304 | |
305 | #ifdef CONFIG_NO_HZ | |
306 | /* Make sure that timer wheel updates are propagated */ | |
307 | if (!in_interrupt() && idle_cpu(smp_processor_id()) && !need_resched()) | |
308 | tick_nohz_stop_sched_tick(); | |
309 | #endif | |
1da177e4 LT |
310 | preempt_enable_no_resched(); |
311 | } | |
312 | ||
313 | /* | |
314 | * This function must run with irqs disabled! | |
315 | */ | |
316 | inline fastcall void raise_softirq_irqoff(unsigned int nr) | |
317 | { | |
318 | __raise_softirq_irqoff(nr); | |
319 | ||
320 | /* | |
321 | * If we're in an interrupt or softirq, we're done | |
322 | * (this also catches softirq-disabled code). We will | |
323 | * actually run the softirq once we return from | |
324 | * the irq or softirq. | |
325 | * | |
326 | * Otherwise we wake up ksoftirqd to make sure we | |
327 | * schedule the softirq soon. | |
328 | */ | |
329 | if (!in_interrupt()) | |
330 | wakeup_softirqd(); | |
331 | } | |
332 | ||
1da177e4 LT |
333 | void fastcall raise_softirq(unsigned int nr) |
334 | { | |
335 | unsigned long flags; | |
336 | ||
337 | local_irq_save(flags); | |
338 | raise_softirq_irqoff(nr); | |
339 | local_irq_restore(flags); | |
340 | } | |
341 | ||
342 | void open_softirq(int nr, void (*action)(struct softirq_action*), void *data) | |
343 | { | |
344 | softirq_vec[nr].data = data; | |
345 | softirq_vec[nr].action = action; | |
346 | } | |
347 | ||
1da177e4 LT |
348 | /* Tasklets */ |
349 | struct tasklet_head | |
350 | { | |
351 | struct tasklet_struct *list; | |
352 | }; | |
353 | ||
354 | /* Some compilers disobey section attribute on statics when not | |
355 | initialized -- RR */ | |
356 | static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec) = { NULL }; | |
357 | static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec) = { NULL }; | |
358 | ||
359 | void fastcall __tasklet_schedule(struct tasklet_struct *t) | |
360 | { | |
361 | unsigned long flags; | |
362 | ||
363 | local_irq_save(flags); | |
364 | t->next = __get_cpu_var(tasklet_vec).list; | |
365 | __get_cpu_var(tasklet_vec).list = t; | |
366 | raise_softirq_irqoff(TASKLET_SOFTIRQ); | |
367 | local_irq_restore(flags); | |
368 | } | |
369 | ||
370 | EXPORT_SYMBOL(__tasklet_schedule); | |
371 | ||
372 | void fastcall __tasklet_hi_schedule(struct tasklet_struct *t) | |
373 | { | |
374 | unsigned long flags; | |
375 | ||
376 | local_irq_save(flags); | |
377 | t->next = __get_cpu_var(tasklet_hi_vec).list; | |
378 | __get_cpu_var(tasklet_hi_vec).list = t; | |
379 | raise_softirq_irqoff(HI_SOFTIRQ); | |
380 | local_irq_restore(flags); | |
381 | } | |
382 | ||
383 | EXPORT_SYMBOL(__tasklet_hi_schedule); | |
384 | ||
385 | static void tasklet_action(struct softirq_action *a) | |
386 | { | |
387 | struct tasklet_struct *list; | |
388 | ||
389 | local_irq_disable(); | |
390 | list = __get_cpu_var(tasklet_vec).list; | |
391 | __get_cpu_var(tasklet_vec).list = NULL; | |
392 | local_irq_enable(); | |
393 | ||
394 | while (list) { | |
395 | struct tasklet_struct *t = list; | |
396 | ||
397 | list = list->next; | |
398 | ||
399 | if (tasklet_trylock(t)) { | |
400 | if (!atomic_read(&t->count)) { | |
401 | if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) | |
402 | BUG(); | |
403 | t->func(t->data); | |
404 | tasklet_unlock(t); | |
405 | continue; | |
406 | } | |
407 | tasklet_unlock(t); | |
408 | } | |
409 | ||
410 | local_irq_disable(); | |
411 | t->next = __get_cpu_var(tasklet_vec).list; | |
412 | __get_cpu_var(tasklet_vec).list = t; | |
413 | __raise_softirq_irqoff(TASKLET_SOFTIRQ); | |
414 | local_irq_enable(); | |
415 | } | |
416 | } | |
417 | ||
418 | static void tasklet_hi_action(struct softirq_action *a) | |
419 | { | |
420 | struct tasklet_struct *list; | |
421 | ||
422 | local_irq_disable(); | |
423 | list = __get_cpu_var(tasklet_hi_vec).list; | |
424 | __get_cpu_var(tasklet_hi_vec).list = NULL; | |
425 | local_irq_enable(); | |
426 | ||
427 | while (list) { | |
428 | struct tasklet_struct *t = list; | |
429 | ||
430 | list = list->next; | |
431 | ||
432 | if (tasklet_trylock(t)) { | |
433 | if (!atomic_read(&t->count)) { | |
434 | if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) | |
435 | BUG(); | |
436 | t->func(t->data); | |
437 | tasklet_unlock(t); | |
438 | continue; | |
439 | } | |
440 | tasklet_unlock(t); | |
441 | } | |
442 | ||
443 | local_irq_disable(); | |
444 | t->next = __get_cpu_var(tasklet_hi_vec).list; | |
445 | __get_cpu_var(tasklet_hi_vec).list = t; | |
446 | __raise_softirq_irqoff(HI_SOFTIRQ); | |
447 | local_irq_enable(); | |
448 | } | |
449 | } | |
450 | ||
451 | ||
452 | void tasklet_init(struct tasklet_struct *t, | |
453 | void (*func)(unsigned long), unsigned long data) | |
454 | { | |
455 | t->next = NULL; | |
456 | t->state = 0; | |
457 | atomic_set(&t->count, 0); | |
458 | t->func = func; | |
459 | t->data = data; | |
460 | } | |
461 | ||
462 | EXPORT_SYMBOL(tasklet_init); | |
463 | ||
464 | void tasklet_kill(struct tasklet_struct *t) | |
465 | { | |
466 | if (in_interrupt()) | |
467 | printk("Attempt to kill tasklet from interrupt\n"); | |
468 | ||
469 | while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) { | |
470 | do | |
471 | yield(); | |
472 | while (test_bit(TASKLET_STATE_SCHED, &t->state)); | |
473 | } | |
474 | tasklet_unlock_wait(t); | |
475 | clear_bit(TASKLET_STATE_SCHED, &t->state); | |
476 | } | |
477 | ||
478 | EXPORT_SYMBOL(tasklet_kill); | |
479 | ||
480 | void __init softirq_init(void) | |
481 | { | |
482 | open_softirq(TASKLET_SOFTIRQ, tasklet_action, NULL); | |
483 | open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL); | |
484 | } | |
485 | ||
486 | static int ksoftirqd(void * __bind_cpu) | |
487 | { | |
1da177e4 LT |
488 | set_current_state(TASK_INTERRUPTIBLE); |
489 | ||
490 | while (!kthread_should_stop()) { | |
491 | preempt_disable(); | |
492 | if (!local_softirq_pending()) { | |
493 | preempt_enable_no_resched(); | |
494 | schedule(); | |
495 | preempt_disable(); | |
496 | } | |
497 | ||
498 | __set_current_state(TASK_RUNNING); | |
499 | ||
500 | while (local_softirq_pending()) { | |
501 | /* Preempt disable stops cpu going offline. | |
502 | If already offline, we'll be on wrong CPU: | |
503 | don't process */ | |
504 | if (cpu_is_offline((long)__bind_cpu)) | |
505 | goto wait_to_die; | |
506 | do_softirq(); | |
507 | preempt_enable_no_resched(); | |
508 | cond_resched(); | |
509 | preempt_disable(); | |
510 | } | |
511 | preempt_enable(); | |
512 | set_current_state(TASK_INTERRUPTIBLE); | |
513 | } | |
514 | __set_current_state(TASK_RUNNING); | |
515 | return 0; | |
516 | ||
517 | wait_to_die: | |
518 | preempt_enable(); | |
519 | /* Wait for kthread_stop */ | |
520 | set_current_state(TASK_INTERRUPTIBLE); | |
521 | while (!kthread_should_stop()) { | |
522 | schedule(); | |
523 | set_current_state(TASK_INTERRUPTIBLE); | |
524 | } | |
525 | __set_current_state(TASK_RUNNING); | |
526 | return 0; | |
527 | } | |
528 | ||
529 | #ifdef CONFIG_HOTPLUG_CPU | |
530 | /* | |
531 | * tasklet_kill_immediate is called to remove a tasklet which can already be | |
532 | * scheduled for execution on @cpu. | |
533 | * | |
534 | * Unlike tasklet_kill, this function removes the tasklet | |
535 | * _immediately_, even if the tasklet is in TASKLET_STATE_SCHED state. | |
536 | * | |
537 | * When this function is called, @cpu must be in the CPU_DEAD state. | |
538 | */ | |
539 | void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu) | |
540 | { | |
541 | struct tasklet_struct **i; | |
542 | ||
543 | BUG_ON(cpu_online(cpu)); | |
544 | BUG_ON(test_bit(TASKLET_STATE_RUN, &t->state)); | |
545 | ||
546 | if (!test_bit(TASKLET_STATE_SCHED, &t->state)) | |
547 | return; | |
548 | ||
549 | /* CPU is dead, so no lock needed. */ | |
550 | for (i = &per_cpu(tasklet_vec, cpu).list; *i; i = &(*i)->next) { | |
551 | if (*i == t) { | |
552 | *i = t->next; | |
553 | return; | |
554 | } | |
555 | } | |
556 | BUG(); | |
557 | } | |
558 | ||
559 | static void takeover_tasklets(unsigned int cpu) | |
560 | { | |
561 | struct tasklet_struct **i; | |
562 | ||
563 | /* CPU is dead, so no lock needed. */ | |
564 | local_irq_disable(); | |
565 | ||
566 | /* Find end, append list for that CPU. */ | |
567 | for (i = &__get_cpu_var(tasklet_vec).list; *i; i = &(*i)->next); | |
568 | *i = per_cpu(tasklet_vec, cpu).list; | |
569 | per_cpu(tasklet_vec, cpu).list = NULL; | |
570 | raise_softirq_irqoff(TASKLET_SOFTIRQ); | |
571 | ||
572 | for (i = &__get_cpu_var(tasklet_hi_vec).list; *i; i = &(*i)->next); | |
573 | *i = per_cpu(tasklet_hi_vec, cpu).list; | |
574 | per_cpu(tasklet_hi_vec, cpu).list = NULL; | |
575 | raise_softirq_irqoff(HI_SOFTIRQ); | |
576 | ||
577 | local_irq_enable(); | |
578 | } | |
579 | #endif /* CONFIG_HOTPLUG_CPU */ | |
580 | ||
8c78f307 | 581 | static int __cpuinit cpu_callback(struct notifier_block *nfb, |
1da177e4 LT |
582 | unsigned long action, |
583 | void *hcpu) | |
584 | { | |
585 | int hotcpu = (unsigned long)hcpu; | |
586 | struct task_struct *p; | |
587 | ||
588 | switch (action) { | |
589 | case CPU_UP_PREPARE: | |
8bb78442 | 590 | case CPU_UP_PREPARE_FROZEN: |
1da177e4 LT |
591 | p = kthread_create(ksoftirqd, hcpu, "ksoftirqd/%d", hotcpu); |
592 | if (IS_ERR(p)) { | |
593 | printk("ksoftirqd for %i failed\n", hotcpu); | |
594 | return NOTIFY_BAD; | |
595 | } | |
596 | kthread_bind(p, hotcpu); | |
597 | per_cpu(ksoftirqd, hotcpu) = p; | |
598 | break; | |
599 | case CPU_ONLINE: | |
8bb78442 | 600 | case CPU_ONLINE_FROZEN: |
1da177e4 LT |
601 | wake_up_process(per_cpu(ksoftirqd, hotcpu)); |
602 | break; | |
603 | #ifdef CONFIG_HOTPLUG_CPU | |
604 | case CPU_UP_CANCELED: | |
8bb78442 | 605 | case CPU_UP_CANCELED_FROZEN: |
fc75cdfa HC |
606 | if (!per_cpu(ksoftirqd, hotcpu)) |
607 | break; | |
1da177e4 | 608 | /* Unbind so it can run. Fall thru. */ |
a4c4af7c HC |
609 | kthread_bind(per_cpu(ksoftirqd, hotcpu), |
610 | any_online_cpu(cpu_online_map)); | |
1da177e4 | 611 | case CPU_DEAD: |
1c6b4aa9 ST |
612 | case CPU_DEAD_FROZEN: { |
613 | struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; | |
614 | ||
1da177e4 LT |
615 | p = per_cpu(ksoftirqd, hotcpu); |
616 | per_cpu(ksoftirqd, hotcpu) = NULL; | |
1c6b4aa9 | 617 | sched_setscheduler(p, SCHED_FIFO, ¶m); |
1da177e4 LT |
618 | kthread_stop(p); |
619 | takeover_tasklets(hotcpu); | |
620 | break; | |
1c6b4aa9 | 621 | } |
1da177e4 LT |
622 | #endif /* CONFIG_HOTPLUG_CPU */ |
623 | } | |
624 | return NOTIFY_OK; | |
625 | } | |
626 | ||
8c78f307 | 627 | static struct notifier_block __cpuinitdata cpu_nfb = { |
1da177e4 LT |
628 | .notifier_call = cpu_callback |
629 | }; | |
630 | ||
631 | __init int spawn_ksoftirqd(void) | |
632 | { | |
633 | void *cpu = (void *)(long)smp_processor_id(); | |
07dccf33 AM |
634 | int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu); |
635 | ||
636 | BUG_ON(err == NOTIFY_BAD); | |
1da177e4 LT |
637 | cpu_callback(&cpu_nfb, CPU_ONLINE, cpu); |
638 | register_cpu_notifier(&cpu_nfb); | |
639 | return 0; | |
640 | } | |
78eef01b AM |
641 | |
642 | #ifdef CONFIG_SMP | |
643 | /* | |
644 | * Call a function on all processors | |
645 | */ | |
646 | int on_each_cpu(void (*func) (void *info), void *info, int retry, int wait) | |
647 | { | |
648 | int ret = 0; | |
649 | ||
650 | preempt_disable(); | |
651 | ret = smp_call_function(func, info, retry, wait); | |
652 | local_irq_disable(); | |
653 | func(info); | |
654 | local_irq_enable(); | |
655 | preempt_enable(); | |
656 | return ret; | |
657 | } | |
658 | EXPORT_SYMBOL(on_each_cpu); | |
659 | #endif |