2 * linux/kernel/softirq.c
4 * Copyright (C) 1992 Linus Torvalds
6 * Distribute under GPLv2.
8 * Rewritten. Old one was good in 2.2, but in 2.3 it was immoral. --ANK (990903)
10 * Remote softirq infrastructure is by Jens Axboe.
13 #include <linux/export.h>
14 #include <linux/kernel_stat.h>
15 #include <linux/interrupt.h>
16 #include <linux/init.h>
18 #include <linux/notifier.h>
19 #include <linux/percpu.h>
20 #include <linux/cpu.h>
21 #include <linux/freezer.h>
22 #include <linux/kthread.h>
23 #include <linux/rcupdate.h>
24 #include <linux/ftrace.h>
25 #include <linux/smp.h>
26 #include <linux/smpboot.h>
27 #include <linux/tick.h>
29 #define CREATE_TRACE_POINTS
30 #include <trace/events/irq.h>
33 - No shared variables, all the data are CPU local.
34 - If a softirq needs serialization, let it serialize itself
36 - Even if softirq is serialized, only local cpu is marked for
37 execution. Hence, we get something sort of weak cpu binding.
38 Though it is still not clear, will it result in better locality
42 - NET RX softirq. It is multithreaded and does not require
43 any global serialization.
44 - NET TX softirq. It kicks software netdevice queues, hence
45 it is logically serialized per device, but this serialization
46 is invisible to common code.
47 - Tasklets: serialized wrt itself.
50 #ifndef __ARCH_IRQ_STAT
51 irq_cpustat_t irq_stat
[NR_CPUS
] ____cacheline_aligned
;
52 EXPORT_SYMBOL(irq_stat
);
55 static struct softirq_action softirq_vec
[NR_SOFTIRQS
] __cacheline_aligned_in_smp
;
57 DEFINE_PER_CPU(struct task_struct
*, ksoftirqd
);
59 char *softirq_to_name
[NR_SOFTIRQS
] = {
60 "HI", "TIMER", "NET_TX", "NET_RX", "BLOCK", "BLOCK_IOPOLL",
61 "TASKLET", "SCHED", "HRTIMER", "RCU"
65 * we cannot loop indefinitely here to avoid userspace starvation,
66 * but we also don't want to introduce a worst case 1/HZ latency
67 * to the pending events, so lets the scheduler to balance
68 * the softirq load for us.
70 static void wakeup_softirqd(void)
72 /* Interrupts are disabled: no need to stop preemption */
73 struct task_struct
*tsk
= __this_cpu_read(ksoftirqd
);
75 if (tsk
&& tsk
->state
!= TASK_RUNNING
)
80 * preempt_count and SOFTIRQ_OFFSET usage:
81 * - preempt_count is changed by SOFTIRQ_OFFSET on entering or leaving
83 * - preempt_count is changed by SOFTIRQ_DISABLE_OFFSET (= 2 * SOFTIRQ_OFFSET)
84 * on local_bh_disable or local_bh_enable.
85 * This lets us distinguish between whether we are currently processing
86 * softirq and whether we just have bh disabled.
90 * This one is for softirq.c-internal use,
91 * where hardirqs are disabled legitimately:
93 #ifdef CONFIG_TRACE_IRQFLAGS
94 static void __local_bh_disable(unsigned long ip
, unsigned int cnt
)
98 WARN_ON_ONCE(in_irq());
100 raw_local_irq_save(flags
);
102 * The preempt tracer hooks into add_preempt_count and will break
103 * lockdep because it calls back into lockdep after SOFTIRQ_OFFSET
104 * is set and before current->softirq_enabled is cleared.
105 * We must manually increment preempt_count here and manually
106 * call the trace_preempt_off later.
108 preempt_count() += cnt
;
110 * Were softirqs turned off above:
112 if (softirq_count() == cnt
)
113 trace_softirqs_off(ip
);
114 raw_local_irq_restore(flags
);
116 if (preempt_count() == cnt
)
117 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
119 #else /* !CONFIG_TRACE_IRQFLAGS */
120 static inline void __local_bh_disable(unsigned long ip
, unsigned int cnt
)
122 add_preempt_count(cnt
);
125 #endif /* CONFIG_TRACE_IRQFLAGS */
127 void local_bh_disable(void)
129 __local_bh_disable(_RET_IP_
, SOFTIRQ_DISABLE_OFFSET
);
132 EXPORT_SYMBOL(local_bh_disable
);
134 static void __local_bh_enable(unsigned int cnt
)
136 WARN_ON_ONCE(!irqs_disabled());
138 if (softirq_count() == cnt
)
139 trace_softirqs_on(_RET_IP_
);
140 sub_preempt_count(cnt
);
144 * Special-case - softirqs can safely be enabled in
145 * cond_resched_softirq(), or by __do_softirq(),
146 * without processing still-pending softirqs:
148 void _local_bh_enable(void)
150 WARN_ON_ONCE(in_irq());
151 __local_bh_enable(SOFTIRQ_DISABLE_OFFSET
);
154 EXPORT_SYMBOL(_local_bh_enable
);
156 static inline void _local_bh_enable_ip(unsigned long ip
)
158 WARN_ON_ONCE(in_irq() || irqs_disabled());
159 #ifdef CONFIG_TRACE_IRQFLAGS
163 * Are softirqs going to be turned on now:
165 if (softirq_count() == SOFTIRQ_DISABLE_OFFSET
)
166 trace_softirqs_on(ip
);
168 * Keep preemption disabled until we are done with
169 * softirq processing:
171 sub_preempt_count(SOFTIRQ_DISABLE_OFFSET
- 1);
173 if (unlikely(!in_interrupt() && local_softirq_pending()))
177 #ifdef CONFIG_TRACE_IRQFLAGS
180 preempt_check_resched();
183 void local_bh_enable(void)
185 _local_bh_enable_ip(_RET_IP_
);
187 EXPORT_SYMBOL(local_bh_enable
);
189 void local_bh_enable_ip(unsigned long ip
)
191 _local_bh_enable_ip(ip
);
193 EXPORT_SYMBOL(local_bh_enable_ip
);
196 * We restart softirq processing for at most MAX_SOFTIRQ_RESTART times,
197 * but break the loop if need_resched() is set or after 2 ms.
198 * The MAX_SOFTIRQ_TIME provides a nice upper bound in most cases, but in
199 * certain cases, such as stop_machine(), jiffies may cease to
200 * increment and so we need the MAX_SOFTIRQ_RESTART limit as
201 * well to make sure we eventually return from this method.
203 * These limits have been established via experimentation.
204 * The two things to balance is latency against fairness -
205 * we want to handle softirqs as soon as possible, but they
206 * should not be able to lock up the box.
208 #define MAX_SOFTIRQ_TIME msecs_to_jiffies(2)
209 #define MAX_SOFTIRQ_RESTART 10
211 asmlinkage
void __do_softirq(void)
213 struct softirq_action
*h
;
215 unsigned long end
= jiffies
+ MAX_SOFTIRQ_TIME
;
217 unsigned long old_flags
= current
->flags
;
218 int max_restart
= MAX_SOFTIRQ_RESTART
;
221 * Mask out PF_MEMALLOC s current task context is borrowed for the
222 * softirq. A softirq handled such as network RX might set PF_MEMALLOC
223 * again if the socket is related to swap
225 current
->flags
&= ~PF_MEMALLOC
;
227 pending
= local_softirq_pending();
228 account_irq_enter_time(current
);
230 __local_bh_disable(_RET_IP_
, SOFTIRQ_OFFSET
);
231 lockdep_softirq_enter();
233 cpu
= smp_processor_id();
235 /* Reset the pending bitmask before enabling irqs */
236 set_softirq_pending(0);
244 unsigned int vec_nr
= h
- softirq_vec
;
245 int prev_count
= preempt_count();
247 kstat_incr_softirqs_this_cpu(vec_nr
);
249 trace_softirq_entry(vec_nr
);
251 trace_softirq_exit(vec_nr
);
252 if (unlikely(prev_count
!= preempt_count())) {
253 printk(KERN_ERR
"huh, entered softirq %u %s %p"
254 "with preempt_count %08x,"
255 " exited with %08x?\n", vec_nr
,
256 softirq_to_name
[vec_nr
], h
->action
,
257 prev_count
, preempt_count());
258 preempt_count() = prev_count
;
269 pending
= local_softirq_pending();
271 if (time_before(jiffies
, end
) && !need_resched() &&
278 lockdep_softirq_exit();
280 account_irq_exit_time(current
);
281 __local_bh_enable(SOFTIRQ_OFFSET
);
282 WARN_ON_ONCE(in_interrupt());
283 tsk_restore_flags(current
, old_flags
, PF_MEMALLOC
);
288 asmlinkage
void do_softirq(void)
296 local_irq_save(flags
);
298 pending
= local_softirq_pending();
301 do_softirq_own_stack();
303 local_irq_restore(flags
);
307 * Enter an interrupt context.
311 int cpu
= smp_processor_id();
314 if (is_idle_task(current
) && !in_interrupt()) {
316 * Prevent raise_softirq from needlessly waking up ksoftirqd
317 * here, as softirq will be serviced on return from interrupt.
320 tick_check_idle(cpu
);
327 static inline void invoke_softirq(void)
329 if (!force_irqthreads
) {
331 * We can safely execute softirq on the current stack if
332 * it is the irq stack, because it should be near empty
333 * at this stage. But we have no way to know if the arch
334 * calls irq_exit() on the irq stack. So call softirq
335 * in its own stack to prevent from any overrun on top
336 * of a potentially deep task stack.
338 do_softirq_own_stack();
344 static inline void tick_irq_exit(void)
346 #ifdef CONFIG_NO_HZ_COMMON
347 int cpu
= smp_processor_id();
349 /* Make sure that timer wheel updates are propagated */
350 if ((idle_cpu(cpu
) && !need_resched()) || tick_nohz_full_cpu(cpu
)) {
352 tick_nohz_irq_exit();
358 * Exit an interrupt context. Process softirqs if needed and possible:
362 #ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED
365 WARN_ON_ONCE(!irqs_disabled());
368 account_irq_exit_time(current
);
369 trace_hardirq_exit();
370 sub_preempt_count(HARDIRQ_OFFSET
);
371 if (!in_interrupt() && local_softirq_pending())
379 * This function must run with irqs disabled!
381 inline void raise_softirq_irqoff(unsigned int nr
)
383 __raise_softirq_irqoff(nr
);
386 * If we're in an interrupt or softirq, we're done
387 * (this also catches softirq-disabled code). We will
388 * actually run the softirq once we return from
389 * the irq or softirq.
391 * Otherwise we wake up ksoftirqd to make sure we
392 * schedule the softirq soon.
398 void raise_softirq(unsigned int nr
)
402 local_irq_save(flags
);
403 raise_softirq_irqoff(nr
);
404 local_irq_restore(flags
);
407 void __raise_softirq_irqoff(unsigned int nr
)
409 trace_softirq_raise(nr
);
410 or_softirq_pending(1UL << nr
);
413 void open_softirq(int nr
, void (*action
)(struct softirq_action
*))
415 softirq_vec
[nr
].action
= action
;
423 struct tasklet_struct
*head
;
424 struct tasklet_struct
**tail
;
427 static DEFINE_PER_CPU(struct tasklet_head
, tasklet_vec
);
428 static DEFINE_PER_CPU(struct tasklet_head
, tasklet_hi_vec
);
430 void __tasklet_schedule(struct tasklet_struct
*t
)
434 local_irq_save(flags
);
436 *__this_cpu_read(tasklet_vec
.tail
) = t
;
437 __this_cpu_write(tasklet_vec
.tail
, &(t
->next
));
438 raise_softirq_irqoff(TASKLET_SOFTIRQ
);
439 local_irq_restore(flags
);
442 EXPORT_SYMBOL(__tasklet_schedule
);
444 void __tasklet_hi_schedule(struct tasklet_struct
*t
)
448 local_irq_save(flags
);
450 *__this_cpu_read(tasklet_hi_vec
.tail
) = t
;
451 __this_cpu_write(tasklet_hi_vec
.tail
, &(t
->next
));
452 raise_softirq_irqoff(HI_SOFTIRQ
);
453 local_irq_restore(flags
);
456 EXPORT_SYMBOL(__tasklet_hi_schedule
);
458 void __tasklet_hi_schedule_first(struct tasklet_struct
*t
)
460 BUG_ON(!irqs_disabled());
462 t
->next
= __this_cpu_read(tasklet_hi_vec
.head
);
463 __this_cpu_write(tasklet_hi_vec
.head
, t
);
464 __raise_softirq_irqoff(HI_SOFTIRQ
);
467 EXPORT_SYMBOL(__tasklet_hi_schedule_first
);
469 static void tasklet_action(struct softirq_action
*a
)
471 struct tasklet_struct
*list
;
474 list
= __this_cpu_read(tasklet_vec
.head
);
475 __this_cpu_write(tasklet_vec
.head
, NULL
);
476 __this_cpu_write(tasklet_vec
.tail
, &__get_cpu_var(tasklet_vec
).head
);
480 struct tasklet_struct
*t
= list
;
484 if (tasklet_trylock(t
)) {
485 if (!atomic_read(&t
->count
)) {
486 if (!test_and_clear_bit(TASKLET_STATE_SCHED
, &t
->state
))
497 *__this_cpu_read(tasklet_vec
.tail
) = t
;
498 __this_cpu_write(tasklet_vec
.tail
, &(t
->next
));
499 __raise_softirq_irqoff(TASKLET_SOFTIRQ
);
504 static void tasklet_hi_action(struct softirq_action
*a
)
506 struct tasklet_struct
*list
;
509 list
= __this_cpu_read(tasklet_hi_vec
.head
);
510 __this_cpu_write(tasklet_hi_vec
.head
, NULL
);
511 __this_cpu_write(tasklet_hi_vec
.tail
, &__get_cpu_var(tasklet_hi_vec
).head
);
515 struct tasklet_struct
*t
= list
;
519 if (tasklet_trylock(t
)) {
520 if (!atomic_read(&t
->count
)) {
521 if (!test_and_clear_bit(TASKLET_STATE_SCHED
, &t
->state
))
532 *__this_cpu_read(tasklet_hi_vec
.tail
) = t
;
533 __this_cpu_write(tasklet_hi_vec
.tail
, &(t
->next
));
534 __raise_softirq_irqoff(HI_SOFTIRQ
);
540 void tasklet_init(struct tasklet_struct
*t
,
541 void (*func
)(unsigned long), unsigned long data
)
545 atomic_set(&t
->count
, 0);
550 EXPORT_SYMBOL(tasklet_init
);
552 void tasklet_kill(struct tasklet_struct
*t
)
555 printk("Attempt to kill tasklet from interrupt\n");
557 while (test_and_set_bit(TASKLET_STATE_SCHED
, &t
->state
)) {
560 } while (test_bit(TASKLET_STATE_SCHED
, &t
->state
));
562 tasklet_unlock_wait(t
);
563 clear_bit(TASKLET_STATE_SCHED
, &t
->state
);
566 EXPORT_SYMBOL(tasklet_kill
);
573 * The trampoline is called when the hrtimer expires. It schedules a tasklet
574 * to run __tasklet_hrtimer_trampoline() which in turn will call the intended
575 * hrtimer callback, but from softirq context.
577 static enum hrtimer_restart
__hrtimer_tasklet_trampoline(struct hrtimer
*timer
)
579 struct tasklet_hrtimer
*ttimer
=
580 container_of(timer
, struct tasklet_hrtimer
, timer
);
582 tasklet_hi_schedule(&ttimer
->tasklet
);
583 return HRTIMER_NORESTART
;
587 * Helper function which calls the hrtimer callback from
588 * tasklet/softirq context
590 static void __tasklet_hrtimer_trampoline(unsigned long data
)
592 struct tasklet_hrtimer
*ttimer
= (void *)data
;
593 enum hrtimer_restart restart
;
595 restart
= ttimer
->function(&ttimer
->timer
);
596 if (restart
!= HRTIMER_NORESTART
)
597 hrtimer_restart(&ttimer
->timer
);
601 * tasklet_hrtimer_init - Init a tasklet/hrtimer combo for softirq callbacks
602 * @ttimer: tasklet_hrtimer which is initialized
603 * @function: hrtimer callback function which gets called from softirq context
604 * @which_clock: clock id (CLOCK_MONOTONIC/CLOCK_REALTIME)
605 * @mode: hrtimer mode (HRTIMER_MODE_ABS/HRTIMER_MODE_REL)
607 void tasklet_hrtimer_init(struct tasklet_hrtimer
*ttimer
,
608 enum hrtimer_restart (*function
)(struct hrtimer
*),
609 clockid_t which_clock
, enum hrtimer_mode mode
)
611 hrtimer_init(&ttimer
->timer
, which_clock
, mode
);
612 ttimer
->timer
.function
= __hrtimer_tasklet_trampoline
;
613 tasklet_init(&ttimer
->tasklet
, __tasklet_hrtimer_trampoline
,
614 (unsigned long)ttimer
);
615 ttimer
->function
= function
;
617 EXPORT_SYMBOL_GPL(tasklet_hrtimer_init
);
620 * Remote softirq bits
623 DEFINE_PER_CPU(struct list_head
[NR_SOFTIRQS
], softirq_work_list
);
624 EXPORT_PER_CPU_SYMBOL(softirq_work_list
);
626 static void __local_trigger(struct call_single_data
*cp
, int softirq
)
628 struct list_head
*head
= &__get_cpu_var(softirq_work_list
[softirq
]);
630 list_add_tail(&cp
->list
, head
);
632 /* Trigger the softirq only if the list was previously empty. */
633 if (head
->next
== &cp
->list
)
634 raise_softirq_irqoff(softirq
);
637 #ifdef CONFIG_USE_GENERIC_SMP_HELPERS
638 static void remote_softirq_receive(void *data
)
640 struct call_single_data
*cp
= data
;
644 softirq
= *(int *)cp
->info
;
645 local_irq_save(flags
);
646 __local_trigger(cp
, softirq
);
647 local_irq_restore(flags
);
650 static int __try_remote_softirq(struct call_single_data
*cp
, int cpu
, int softirq
)
652 if (cpu_online(cpu
)) {
653 cp
->func
= remote_softirq_receive
;
657 __smp_call_function_single(cpu
, cp
, 0);
662 #else /* CONFIG_USE_GENERIC_SMP_HELPERS */
663 static int __try_remote_softirq(struct call_single_data
*cp
, int cpu
, int softirq
)
670 * __send_remote_softirq - try to schedule softirq work on a remote cpu
671 * @cp: private SMP call function data area
672 * @cpu: the remote cpu
673 * @this_cpu: the currently executing cpu
674 * @softirq: the softirq for the work
676 * Attempt to schedule softirq work on a remote cpu. If this cannot be
677 * done, the work is instead queued up on the local cpu.
679 * Interrupts must be disabled.
681 void __send_remote_softirq(struct call_single_data
*cp
, int cpu
, int this_cpu
, int softirq
)
683 if (cpu
== this_cpu
|| __try_remote_softirq(cp
, cpu
, softirq
))
684 __local_trigger(cp
, softirq
);
686 EXPORT_SYMBOL(__send_remote_softirq
);
689 * send_remote_softirq - try to schedule softirq work on a remote cpu
690 * @cp: private SMP call function data area
691 * @cpu: the remote cpu
692 * @softirq: the softirq for the work
694 * Like __send_remote_softirq except that disabling interrupts and
695 * computing the current cpu is done for the caller.
697 void send_remote_softirq(struct call_single_data
*cp
, int cpu
, int softirq
)
702 local_irq_save(flags
);
703 this_cpu
= smp_processor_id();
704 __send_remote_softirq(cp
, cpu
, this_cpu
, softirq
);
705 local_irq_restore(flags
);
707 EXPORT_SYMBOL(send_remote_softirq
);
709 static int remote_softirq_cpu_notify(struct notifier_block
*self
,
710 unsigned long action
, void *hcpu
)
713 * If a CPU goes away, splice its entries to the current CPU
714 * and trigger a run of the softirq
716 if (action
== CPU_DEAD
|| action
== CPU_DEAD_FROZEN
) {
717 int cpu
= (unsigned long) hcpu
;
721 for (i
= 0; i
< NR_SOFTIRQS
; i
++) {
722 struct list_head
*head
= &per_cpu(softirq_work_list
[i
], cpu
);
723 struct list_head
*local_head
;
725 if (list_empty(head
))
728 local_head
= &__get_cpu_var(softirq_work_list
[i
]);
729 list_splice_init(head
, local_head
);
730 raise_softirq_irqoff(i
);
738 static struct notifier_block remote_softirq_cpu_notifier
= {
739 .notifier_call
= remote_softirq_cpu_notify
,
742 void __init
softirq_init(void)
746 for_each_possible_cpu(cpu
) {
749 per_cpu(tasklet_vec
, cpu
).tail
=
750 &per_cpu(tasklet_vec
, cpu
).head
;
751 per_cpu(tasklet_hi_vec
, cpu
).tail
=
752 &per_cpu(tasklet_hi_vec
, cpu
).head
;
753 for (i
= 0; i
< NR_SOFTIRQS
; i
++)
754 INIT_LIST_HEAD(&per_cpu(softirq_work_list
[i
], cpu
));
757 register_hotcpu_notifier(&remote_softirq_cpu_notifier
);
759 open_softirq(TASKLET_SOFTIRQ
, tasklet_action
);
760 open_softirq(HI_SOFTIRQ
, tasklet_hi_action
);
763 static int ksoftirqd_should_run(unsigned int cpu
)
765 return local_softirq_pending();
768 static void run_ksoftirqd(unsigned int cpu
)
771 if (local_softirq_pending()) {
773 rcu_note_context_switch(cpu
);
781 #ifdef CONFIG_HOTPLUG_CPU
783 * tasklet_kill_immediate is called to remove a tasklet which can already be
784 * scheduled for execution on @cpu.
786 * Unlike tasklet_kill, this function removes the tasklet
787 * _immediately_, even if the tasklet is in TASKLET_STATE_SCHED state.
789 * When this function is called, @cpu must be in the CPU_DEAD state.
791 void tasklet_kill_immediate(struct tasklet_struct
*t
, unsigned int cpu
)
793 struct tasklet_struct
**i
;
795 BUG_ON(cpu_online(cpu
));
796 BUG_ON(test_bit(TASKLET_STATE_RUN
, &t
->state
));
798 if (!test_bit(TASKLET_STATE_SCHED
, &t
->state
))
801 /* CPU is dead, so no lock needed. */
802 for (i
= &per_cpu(tasklet_vec
, cpu
).head
; *i
; i
= &(*i
)->next
) {
805 /* If this was the tail element, move the tail ptr */
807 per_cpu(tasklet_vec
, cpu
).tail
= i
;
814 static void takeover_tasklets(unsigned int cpu
)
816 /* CPU is dead, so no lock needed. */
819 /* Find end, append list for that CPU. */
820 if (&per_cpu(tasklet_vec
, cpu
).head
!= per_cpu(tasklet_vec
, cpu
).tail
) {
821 *__this_cpu_read(tasklet_vec
.tail
) = per_cpu(tasklet_vec
, cpu
).head
;
822 this_cpu_write(tasklet_vec
.tail
, per_cpu(tasklet_vec
, cpu
).tail
);
823 per_cpu(tasklet_vec
, cpu
).head
= NULL
;
824 per_cpu(tasklet_vec
, cpu
).tail
= &per_cpu(tasklet_vec
, cpu
).head
;
826 raise_softirq_irqoff(TASKLET_SOFTIRQ
);
828 if (&per_cpu(tasklet_hi_vec
, cpu
).head
!= per_cpu(tasklet_hi_vec
, cpu
).tail
) {
829 *__this_cpu_read(tasklet_hi_vec
.tail
) = per_cpu(tasklet_hi_vec
, cpu
).head
;
830 __this_cpu_write(tasklet_hi_vec
.tail
, per_cpu(tasklet_hi_vec
, cpu
).tail
);
831 per_cpu(tasklet_hi_vec
, cpu
).head
= NULL
;
832 per_cpu(tasklet_hi_vec
, cpu
).tail
= &per_cpu(tasklet_hi_vec
, cpu
).head
;
834 raise_softirq_irqoff(HI_SOFTIRQ
);
838 #endif /* CONFIG_HOTPLUG_CPU */
840 static int cpu_callback(struct notifier_block
*nfb
,
841 unsigned long action
,
845 #ifdef CONFIG_HOTPLUG_CPU
847 case CPU_DEAD_FROZEN
:
848 takeover_tasklets((unsigned long)hcpu
);
850 #endif /* CONFIG_HOTPLUG_CPU */
855 static struct notifier_block cpu_nfb
= {
856 .notifier_call
= cpu_callback
859 static struct smp_hotplug_thread softirq_threads
= {
861 .thread_should_run
= ksoftirqd_should_run
,
862 .thread_fn
= run_ksoftirqd
,
863 .thread_comm
= "ksoftirqd/%u",
866 static __init
int spawn_ksoftirqd(void)
868 register_cpu_notifier(&cpu_nfb
);
870 BUG_ON(smpboot_register_percpu_thread(&softirq_threads
));
874 early_initcall(spawn_ksoftirqd
);
877 * [ These __weak aliases are kept in a separate compilation unit, so that
878 * GCC does not inline them incorrectly. ]
881 int __init __weak
early_irq_init(void)
886 int __init __weak
arch_probe_nr_irqs(void)
888 return NR_IRQS_LEGACY
;
891 int __init __weak
arch_early_irq_init(void)