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> | |
17 | #include <linux/kthread.h> | |
18 | #include <linux/rcupdate.h> | |
78eef01b | 19 | #include <linux/smp.h> |
79bf2bb3 | 20 | #include <linux/tick.h> |
1da177e4 LT |
21 | |
22 | #include <asm/irq.h> | |
23 | /* | |
24 | - No shared variables, all the data are CPU local. | |
25 | - If a softirq needs serialization, let it serialize itself | |
26 | by its own spinlocks. | |
27 | - Even if softirq is serialized, only local cpu is marked for | |
28 | execution. Hence, we get something sort of weak cpu binding. | |
29 | Though it is still not clear, will it result in better locality | |
30 | or will not. | |
31 | ||
32 | Examples: | |
33 | - NET RX softirq. It is multithreaded and does not require | |
34 | any global serialization. | |
35 | - NET TX softirq. It kicks software netdevice queues, hence | |
36 | it is logically serialized per device, but this serialization | |
37 | is invisible to common code. | |
38 | - Tasklets: serialized wrt itself. | |
39 | */ | |
40 | ||
41 | #ifndef __ARCH_IRQ_STAT | |
42 | irq_cpustat_t irq_stat[NR_CPUS] ____cacheline_aligned; | |
43 | EXPORT_SYMBOL(irq_stat); | |
44 | #endif | |
45 | ||
46 | static struct softirq_action softirq_vec[32] __cacheline_aligned_in_smp; | |
47 | ||
48 | static DEFINE_PER_CPU(struct task_struct *, ksoftirqd); | |
49 | ||
50 | /* | |
51 | * we cannot loop indefinitely here to avoid userspace starvation, | |
52 | * but we also don't want to introduce a worst case 1/HZ latency | |
53 | * to the pending events, so lets the scheduler to balance | |
54 | * the softirq load for us. | |
55 | */ | |
56 | static inline void wakeup_softirqd(void) | |
57 | { | |
58 | /* Interrupts are disabled: no need to stop preemption */ | |
59 | struct task_struct *tsk = __get_cpu_var(ksoftirqd); | |
60 | ||
61 | if (tsk && tsk->state != TASK_RUNNING) | |
62 | wake_up_process(tsk); | |
63 | } | |
64 | ||
de30a2b3 IM |
65 | /* |
66 | * This one is for softirq.c-internal use, | |
67 | * where hardirqs are disabled legitimately: | |
68 | */ | |
3c829c36 | 69 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 IM |
70 | static void __local_bh_disable(unsigned long ip) |
71 | { | |
72 | unsigned long flags; | |
73 | ||
74 | WARN_ON_ONCE(in_irq()); | |
75 | ||
76 | raw_local_irq_save(flags); | |
77 | add_preempt_count(SOFTIRQ_OFFSET); | |
78 | /* | |
79 | * Were softirqs turned off above: | |
80 | */ | |
81 | if (softirq_count() == SOFTIRQ_OFFSET) | |
82 | trace_softirqs_off(ip); | |
83 | raw_local_irq_restore(flags); | |
84 | } | |
3c829c36 TC |
85 | #else /* !CONFIG_TRACE_IRQFLAGS */ |
86 | static inline void __local_bh_disable(unsigned long ip) | |
87 | { | |
88 | add_preempt_count(SOFTIRQ_OFFSET); | |
89 | barrier(); | |
90 | } | |
91 | #endif /* CONFIG_TRACE_IRQFLAGS */ | |
de30a2b3 IM |
92 | |
93 | void local_bh_disable(void) | |
94 | { | |
95 | __local_bh_disable((unsigned long)__builtin_return_address(0)); | |
96 | } | |
97 | ||
98 | EXPORT_SYMBOL(local_bh_disable); | |
99 | ||
100 | void __local_bh_enable(void) | |
101 | { | |
102 | WARN_ON_ONCE(in_irq()); | |
103 | ||
104 | /* | |
105 | * softirqs should never be enabled by __local_bh_enable(), | |
106 | * it always nests inside local_bh_enable() sections: | |
107 | */ | |
108 | WARN_ON_ONCE(softirq_count() == SOFTIRQ_OFFSET); | |
109 | ||
110 | sub_preempt_count(SOFTIRQ_OFFSET); | |
111 | } | |
112 | EXPORT_SYMBOL_GPL(__local_bh_enable); | |
113 | ||
114 | /* | |
115 | * Special-case - softirqs can safely be enabled in | |
116 | * cond_resched_softirq(), or by __do_softirq(), | |
117 | * without processing still-pending softirqs: | |
118 | */ | |
119 | void _local_bh_enable(void) | |
120 | { | |
121 | WARN_ON_ONCE(in_irq()); | |
122 | WARN_ON_ONCE(!irqs_disabled()); | |
123 | ||
124 | if (softirq_count() == SOFTIRQ_OFFSET) | |
125 | trace_softirqs_on((unsigned long)__builtin_return_address(0)); | |
126 | sub_preempt_count(SOFTIRQ_OFFSET); | |
127 | } | |
128 | ||
129 | EXPORT_SYMBOL(_local_bh_enable); | |
130 | ||
131 | void local_bh_enable(void) | |
132 | { | |
3c829c36 | 133 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 IM |
134 | unsigned long flags; |
135 | ||
136 | WARN_ON_ONCE(in_irq()); | |
3c829c36 | 137 | #endif |
de30a2b3 IM |
138 | WARN_ON_ONCE(irqs_disabled()); |
139 | ||
3c829c36 | 140 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 | 141 | local_irq_save(flags); |
3c829c36 | 142 | #endif |
de30a2b3 IM |
143 | /* |
144 | * Are softirqs going to be turned on now: | |
145 | */ | |
146 | if (softirq_count() == SOFTIRQ_OFFSET) | |
147 | trace_softirqs_on((unsigned long)__builtin_return_address(0)); | |
148 | /* | |
149 | * Keep preemption disabled until we are done with | |
150 | * softirq processing: | |
151 | */ | |
152 | sub_preempt_count(SOFTIRQ_OFFSET - 1); | |
153 | ||
154 | if (unlikely(!in_interrupt() && local_softirq_pending())) | |
155 | do_softirq(); | |
156 | ||
157 | dec_preempt_count(); | |
3c829c36 | 158 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 | 159 | local_irq_restore(flags); |
3c829c36 | 160 | #endif |
de30a2b3 IM |
161 | preempt_check_resched(); |
162 | } | |
163 | EXPORT_SYMBOL(local_bh_enable); | |
164 | ||
165 | void local_bh_enable_ip(unsigned long ip) | |
166 | { | |
3c829c36 | 167 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 IM |
168 | unsigned long flags; |
169 | ||
170 | WARN_ON_ONCE(in_irq()); | |
171 | ||
172 | local_irq_save(flags); | |
3c829c36 | 173 | #endif |
de30a2b3 IM |
174 | /* |
175 | * Are softirqs going to be turned on now: | |
176 | */ | |
177 | if (softirq_count() == SOFTIRQ_OFFSET) | |
178 | trace_softirqs_on(ip); | |
179 | /* | |
180 | * Keep preemption disabled until we are done with | |
181 | * softirq processing: | |
182 | */ | |
183 | sub_preempt_count(SOFTIRQ_OFFSET - 1); | |
184 | ||
185 | if (unlikely(!in_interrupt() && local_softirq_pending())) | |
186 | do_softirq(); | |
187 | ||
188 | dec_preempt_count(); | |
3c829c36 | 189 | #ifdef CONFIG_TRACE_IRQFLAGS |
de30a2b3 | 190 | local_irq_restore(flags); |
3c829c36 | 191 | #endif |
de30a2b3 IM |
192 | preempt_check_resched(); |
193 | } | |
194 | EXPORT_SYMBOL(local_bh_enable_ip); | |
195 | ||
1da177e4 LT |
196 | /* |
197 | * We restart softirq processing MAX_SOFTIRQ_RESTART times, | |
198 | * and we fall back to softirqd after that. | |
199 | * | |
200 | * This number has been established via experimentation. | |
201 | * The two things to balance is latency against fairness - | |
202 | * we want to handle softirqs as soon as possible, but they | |
203 | * should not be able to lock up the box. | |
204 | */ | |
205 | #define MAX_SOFTIRQ_RESTART 10 | |
206 | ||
207 | asmlinkage void __do_softirq(void) | |
208 | { | |
209 | struct softirq_action *h; | |
210 | __u32 pending; | |
211 | int max_restart = MAX_SOFTIRQ_RESTART; | |
212 | int cpu; | |
213 | ||
214 | pending = local_softirq_pending(); | |
829035fd PM |
215 | account_system_vtime(current); |
216 | ||
de30a2b3 IM |
217 | __local_bh_disable((unsigned long)__builtin_return_address(0)); |
218 | trace_softirq_enter(); | |
1da177e4 | 219 | |
1da177e4 LT |
220 | cpu = smp_processor_id(); |
221 | restart: | |
222 | /* Reset the pending bitmask before enabling irqs */ | |
3f74478b | 223 | set_softirq_pending(0); |
1da177e4 | 224 | |
c70f5d66 | 225 | local_irq_enable(); |
1da177e4 LT |
226 | |
227 | h = softirq_vec; | |
228 | ||
229 | do { | |
230 | if (pending & 1) { | |
231 | h->action(h); | |
232 | rcu_bh_qsctr_inc(cpu); | |
233 | } | |
234 | h++; | |
235 | pending >>= 1; | |
236 | } while (pending); | |
237 | ||
c70f5d66 | 238 | local_irq_disable(); |
1da177e4 LT |
239 | |
240 | pending = local_softirq_pending(); | |
241 | if (pending && --max_restart) | |
242 | goto restart; | |
243 | ||
244 | if (pending) | |
245 | wakeup_softirqd(); | |
246 | ||
de30a2b3 | 247 | trace_softirq_exit(); |
829035fd PM |
248 | |
249 | account_system_vtime(current); | |
de30a2b3 | 250 | _local_bh_enable(); |
1da177e4 LT |
251 | } |
252 | ||
253 | #ifndef __ARCH_HAS_DO_SOFTIRQ | |
254 | ||
255 | asmlinkage void do_softirq(void) | |
256 | { | |
257 | __u32 pending; | |
258 | unsigned long flags; | |
259 | ||
260 | if (in_interrupt()) | |
261 | return; | |
262 | ||
263 | local_irq_save(flags); | |
264 | ||
265 | pending = local_softirq_pending(); | |
266 | ||
267 | if (pending) | |
268 | __do_softirq(); | |
269 | ||
270 | local_irq_restore(flags); | |
271 | } | |
272 | ||
273 | EXPORT_SYMBOL(do_softirq); | |
274 | ||
275 | #endif | |
276 | ||
dde4b2b5 IM |
277 | /* |
278 | * Enter an interrupt context. | |
279 | */ | |
280 | void irq_enter(void) | |
281 | { | |
79bf2bb3 TG |
282 | __irq_enter(); |
283 | #ifdef CONFIG_NO_HZ | |
284 | if (idle_cpu(smp_processor_id())) | |
285 | tick_nohz_update_jiffies(); | |
286 | #endif | |
dde4b2b5 IM |
287 | } |
288 | ||
1da177e4 LT |
289 | #ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED |
290 | # define invoke_softirq() __do_softirq() | |
291 | #else | |
292 | # define invoke_softirq() do_softirq() | |
293 | #endif | |
294 | ||
295 | /* | |
296 | * Exit an interrupt context. Process softirqs if needed and possible: | |
297 | */ | |
298 | void irq_exit(void) | |
299 | { | |
300 | account_system_vtime(current); | |
de30a2b3 | 301 | trace_hardirq_exit(); |
1da177e4 LT |
302 | sub_preempt_count(IRQ_EXIT_OFFSET); |
303 | if (!in_interrupt() && local_softirq_pending()) | |
304 | invoke_softirq(); | |
79bf2bb3 TG |
305 | |
306 | #ifdef CONFIG_NO_HZ | |
307 | /* Make sure that timer wheel updates are propagated */ | |
308 | if (!in_interrupt() && idle_cpu(smp_processor_id()) && !need_resched()) | |
309 | tick_nohz_stop_sched_tick(); | |
310 | #endif | |
1da177e4 LT |
311 | preempt_enable_no_resched(); |
312 | } | |
313 | ||
314 | /* | |
315 | * This function must run with irqs disabled! | |
316 | */ | |
317 | inline fastcall void raise_softirq_irqoff(unsigned int nr) | |
318 | { | |
319 | __raise_softirq_irqoff(nr); | |
320 | ||
321 | /* | |
322 | * If we're in an interrupt or softirq, we're done | |
323 | * (this also catches softirq-disabled code). We will | |
324 | * actually run the softirq once we return from | |
325 | * the irq or softirq. | |
326 | * | |
327 | * Otherwise we wake up ksoftirqd to make sure we | |
328 | * schedule the softirq soon. | |
329 | */ | |
330 | if (!in_interrupt()) | |
331 | wakeup_softirqd(); | |
332 | } | |
333 | ||
334 | EXPORT_SYMBOL(raise_softirq_irqoff); | |
335 | ||
336 | void fastcall raise_softirq(unsigned int nr) | |
337 | { | |
338 | unsigned long flags; | |
339 | ||
340 | local_irq_save(flags); | |
341 | raise_softirq_irqoff(nr); | |
342 | local_irq_restore(flags); | |
343 | } | |
344 | ||
345 | void open_softirq(int nr, void (*action)(struct softirq_action*), void *data) | |
346 | { | |
347 | softirq_vec[nr].data = data; | |
348 | softirq_vec[nr].action = action; | |
349 | } | |
350 | ||
1da177e4 LT |
351 | /* Tasklets */ |
352 | struct tasklet_head | |
353 | { | |
354 | struct tasklet_struct *list; | |
355 | }; | |
356 | ||
357 | /* Some compilers disobey section attribute on statics when not | |
358 | initialized -- RR */ | |
359 | static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec) = { NULL }; | |
360 | static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec) = { NULL }; | |
361 | ||
362 | void fastcall __tasklet_schedule(struct tasklet_struct *t) | |
363 | { | |
364 | unsigned long flags; | |
365 | ||
366 | local_irq_save(flags); | |
367 | t->next = __get_cpu_var(tasklet_vec).list; | |
368 | __get_cpu_var(tasklet_vec).list = t; | |
369 | raise_softirq_irqoff(TASKLET_SOFTIRQ); | |
370 | local_irq_restore(flags); | |
371 | } | |
372 | ||
373 | EXPORT_SYMBOL(__tasklet_schedule); | |
374 | ||
375 | void fastcall __tasklet_hi_schedule(struct tasklet_struct *t) | |
376 | { | |
377 | unsigned long flags; | |
378 | ||
379 | local_irq_save(flags); | |
380 | t->next = __get_cpu_var(tasklet_hi_vec).list; | |
381 | __get_cpu_var(tasklet_hi_vec).list = t; | |
382 | raise_softirq_irqoff(HI_SOFTIRQ); | |
383 | local_irq_restore(flags); | |
384 | } | |
385 | ||
386 | EXPORT_SYMBOL(__tasklet_hi_schedule); | |
387 | ||
388 | static void tasklet_action(struct softirq_action *a) | |
389 | { | |
390 | struct tasklet_struct *list; | |
391 | ||
392 | local_irq_disable(); | |
393 | list = __get_cpu_var(tasklet_vec).list; | |
394 | __get_cpu_var(tasklet_vec).list = NULL; | |
395 | local_irq_enable(); | |
396 | ||
397 | while (list) { | |
398 | struct tasklet_struct *t = list; | |
399 | ||
400 | list = list->next; | |
401 | ||
402 | if (tasklet_trylock(t)) { | |
403 | if (!atomic_read(&t->count)) { | |
404 | if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) | |
405 | BUG(); | |
406 | t->func(t->data); | |
407 | tasklet_unlock(t); | |
408 | continue; | |
409 | } | |
410 | tasklet_unlock(t); | |
411 | } | |
412 | ||
413 | local_irq_disable(); | |
414 | t->next = __get_cpu_var(tasklet_vec).list; | |
415 | __get_cpu_var(tasklet_vec).list = t; | |
416 | __raise_softirq_irqoff(TASKLET_SOFTIRQ); | |
417 | local_irq_enable(); | |
418 | } | |
419 | } | |
420 | ||
421 | static void tasklet_hi_action(struct softirq_action *a) | |
422 | { | |
423 | struct tasklet_struct *list; | |
424 | ||
425 | local_irq_disable(); | |
426 | list = __get_cpu_var(tasklet_hi_vec).list; | |
427 | __get_cpu_var(tasklet_hi_vec).list = NULL; | |
428 | local_irq_enable(); | |
429 | ||
430 | while (list) { | |
431 | struct tasklet_struct *t = list; | |
432 | ||
433 | list = list->next; | |
434 | ||
435 | if (tasklet_trylock(t)) { | |
436 | if (!atomic_read(&t->count)) { | |
437 | if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) | |
438 | BUG(); | |
439 | t->func(t->data); | |
440 | tasklet_unlock(t); | |
441 | continue; | |
442 | } | |
443 | tasklet_unlock(t); | |
444 | } | |
445 | ||
446 | local_irq_disable(); | |
447 | t->next = __get_cpu_var(tasklet_hi_vec).list; | |
448 | __get_cpu_var(tasklet_hi_vec).list = t; | |
449 | __raise_softirq_irqoff(HI_SOFTIRQ); | |
450 | local_irq_enable(); | |
451 | } | |
452 | } | |
453 | ||
454 | ||
455 | void tasklet_init(struct tasklet_struct *t, | |
456 | void (*func)(unsigned long), unsigned long data) | |
457 | { | |
458 | t->next = NULL; | |
459 | t->state = 0; | |
460 | atomic_set(&t->count, 0); | |
461 | t->func = func; | |
462 | t->data = data; | |
463 | } | |
464 | ||
465 | EXPORT_SYMBOL(tasklet_init); | |
466 | ||
467 | void tasklet_kill(struct tasklet_struct *t) | |
468 | { | |
469 | if (in_interrupt()) | |
470 | printk("Attempt to kill tasklet from interrupt\n"); | |
471 | ||
472 | while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) { | |
473 | do | |
474 | yield(); | |
475 | while (test_bit(TASKLET_STATE_SCHED, &t->state)); | |
476 | } | |
477 | tasklet_unlock_wait(t); | |
478 | clear_bit(TASKLET_STATE_SCHED, &t->state); | |
479 | } | |
480 | ||
481 | EXPORT_SYMBOL(tasklet_kill); | |
482 | ||
483 | void __init softirq_init(void) | |
484 | { | |
485 | open_softirq(TASKLET_SOFTIRQ, tasklet_action, NULL); | |
486 | open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL); | |
487 | } | |
488 | ||
489 | static int ksoftirqd(void * __bind_cpu) | |
490 | { | |
1da177e4 LT |
491 | current->flags |= PF_NOFREEZE; |
492 | ||
493 | set_current_state(TASK_INTERRUPTIBLE); | |
494 | ||
495 | while (!kthread_should_stop()) { | |
496 | preempt_disable(); | |
497 | if (!local_softirq_pending()) { | |
498 | preempt_enable_no_resched(); | |
499 | schedule(); | |
500 | preempt_disable(); | |
501 | } | |
502 | ||
503 | __set_current_state(TASK_RUNNING); | |
504 | ||
505 | while (local_softirq_pending()) { | |
506 | /* Preempt disable stops cpu going offline. | |
507 | If already offline, we'll be on wrong CPU: | |
508 | don't process */ | |
509 | if (cpu_is_offline((long)__bind_cpu)) | |
510 | goto wait_to_die; | |
511 | do_softirq(); | |
512 | preempt_enable_no_resched(); | |
513 | cond_resched(); | |
514 | preempt_disable(); | |
515 | } | |
516 | preempt_enable(); | |
517 | set_current_state(TASK_INTERRUPTIBLE); | |
518 | } | |
519 | __set_current_state(TASK_RUNNING); | |
520 | return 0; | |
521 | ||
522 | wait_to_die: | |
523 | preempt_enable(); | |
524 | /* Wait for kthread_stop */ | |
525 | set_current_state(TASK_INTERRUPTIBLE); | |
526 | while (!kthread_should_stop()) { | |
527 | schedule(); | |
528 | set_current_state(TASK_INTERRUPTIBLE); | |
529 | } | |
530 | __set_current_state(TASK_RUNNING); | |
531 | return 0; | |
532 | } | |
533 | ||
534 | #ifdef CONFIG_HOTPLUG_CPU | |
535 | /* | |
536 | * tasklet_kill_immediate is called to remove a tasklet which can already be | |
537 | * scheduled for execution on @cpu. | |
538 | * | |
539 | * Unlike tasklet_kill, this function removes the tasklet | |
540 | * _immediately_, even if the tasklet is in TASKLET_STATE_SCHED state. | |
541 | * | |
542 | * When this function is called, @cpu must be in the CPU_DEAD state. | |
543 | */ | |
544 | void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu) | |
545 | { | |
546 | struct tasklet_struct **i; | |
547 | ||
548 | BUG_ON(cpu_online(cpu)); | |
549 | BUG_ON(test_bit(TASKLET_STATE_RUN, &t->state)); | |
550 | ||
551 | if (!test_bit(TASKLET_STATE_SCHED, &t->state)) | |
552 | return; | |
553 | ||
554 | /* CPU is dead, so no lock needed. */ | |
555 | for (i = &per_cpu(tasklet_vec, cpu).list; *i; i = &(*i)->next) { | |
556 | if (*i == t) { | |
557 | *i = t->next; | |
558 | return; | |
559 | } | |
560 | } | |
561 | BUG(); | |
562 | } | |
563 | ||
564 | static void takeover_tasklets(unsigned int cpu) | |
565 | { | |
566 | struct tasklet_struct **i; | |
567 | ||
568 | /* CPU is dead, so no lock needed. */ | |
569 | local_irq_disable(); | |
570 | ||
571 | /* Find end, append list for that CPU. */ | |
572 | for (i = &__get_cpu_var(tasklet_vec).list; *i; i = &(*i)->next); | |
573 | *i = per_cpu(tasklet_vec, cpu).list; | |
574 | per_cpu(tasklet_vec, cpu).list = NULL; | |
575 | raise_softirq_irqoff(TASKLET_SOFTIRQ); | |
576 | ||
577 | for (i = &__get_cpu_var(tasklet_hi_vec).list; *i; i = &(*i)->next); | |
578 | *i = per_cpu(tasklet_hi_vec, cpu).list; | |
579 | per_cpu(tasklet_hi_vec, cpu).list = NULL; | |
580 | raise_softirq_irqoff(HI_SOFTIRQ); | |
581 | ||
582 | local_irq_enable(); | |
583 | } | |
584 | #endif /* CONFIG_HOTPLUG_CPU */ | |
585 | ||
8c78f307 | 586 | static int __cpuinit cpu_callback(struct notifier_block *nfb, |
1da177e4 LT |
587 | unsigned long action, |
588 | void *hcpu) | |
589 | { | |
590 | int hotcpu = (unsigned long)hcpu; | |
591 | struct task_struct *p; | |
592 | ||
593 | switch (action) { | |
594 | case CPU_UP_PREPARE: | |
8bb78442 | 595 | case CPU_UP_PREPARE_FROZEN: |
1da177e4 LT |
596 | p = kthread_create(ksoftirqd, hcpu, "ksoftirqd/%d", hotcpu); |
597 | if (IS_ERR(p)) { | |
598 | printk("ksoftirqd for %i failed\n", hotcpu); | |
599 | return NOTIFY_BAD; | |
600 | } | |
601 | kthread_bind(p, hotcpu); | |
602 | per_cpu(ksoftirqd, hotcpu) = p; | |
603 | break; | |
604 | case CPU_ONLINE: | |
8bb78442 | 605 | case CPU_ONLINE_FROZEN: |
1da177e4 LT |
606 | wake_up_process(per_cpu(ksoftirqd, hotcpu)); |
607 | break; | |
608 | #ifdef CONFIG_HOTPLUG_CPU | |
609 | case CPU_UP_CANCELED: | |
8bb78442 | 610 | case CPU_UP_CANCELED_FROZEN: |
fc75cdfa HC |
611 | if (!per_cpu(ksoftirqd, hotcpu)) |
612 | break; | |
1da177e4 | 613 | /* Unbind so it can run. Fall thru. */ |
a4c4af7c HC |
614 | kthread_bind(per_cpu(ksoftirqd, hotcpu), |
615 | any_online_cpu(cpu_online_map)); | |
1da177e4 | 616 | case CPU_DEAD: |
1c6b4aa9 ST |
617 | case CPU_DEAD_FROZEN: { |
618 | struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; | |
619 | ||
1da177e4 LT |
620 | p = per_cpu(ksoftirqd, hotcpu); |
621 | per_cpu(ksoftirqd, hotcpu) = NULL; | |
1c6b4aa9 | 622 | sched_setscheduler(p, SCHED_FIFO, ¶m); |
1da177e4 LT |
623 | kthread_stop(p); |
624 | takeover_tasklets(hotcpu); | |
625 | break; | |
1c6b4aa9 | 626 | } |
1da177e4 LT |
627 | #endif /* CONFIG_HOTPLUG_CPU */ |
628 | } | |
629 | return NOTIFY_OK; | |
630 | } | |
631 | ||
8c78f307 | 632 | static struct notifier_block __cpuinitdata cpu_nfb = { |
1da177e4 LT |
633 | .notifier_call = cpu_callback |
634 | }; | |
635 | ||
636 | __init int spawn_ksoftirqd(void) | |
637 | { | |
638 | void *cpu = (void *)(long)smp_processor_id(); | |
07dccf33 AM |
639 | int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu); |
640 | ||
641 | BUG_ON(err == NOTIFY_BAD); | |
1da177e4 LT |
642 | cpu_callback(&cpu_nfb, CPU_ONLINE, cpu); |
643 | register_cpu_notifier(&cpu_nfb); | |
644 | return 0; | |
645 | } | |
78eef01b AM |
646 | |
647 | #ifdef CONFIG_SMP | |
648 | /* | |
649 | * Call a function on all processors | |
650 | */ | |
651 | int on_each_cpu(void (*func) (void *info), void *info, int retry, int wait) | |
652 | { | |
653 | int ret = 0; | |
654 | ||
655 | preempt_disable(); | |
656 | ret = smp_call_function(func, info, retry, wait); | |
657 | local_irq_disable(); | |
658 | func(info); | |
659 | local_irq_enable(); | |
660 | preempt_enable(); | |
661 | return ret; | |
662 | } | |
663 | EXPORT_SYMBOL(on_each_cpu); | |
664 | #endif |