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kernel/softirq.c
18.1 KB
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// SPDX-License-Identifier: GPL-2.0-only |
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/* * linux/kernel/softirq.c * * Copyright (C) 1992 Linus Torvalds * |
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* Rewritten. Old one was good in 2.2, but in 2.3 it was immoral. --ANK (990903) |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/export.h> |
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#include <linux/kernel_stat.h> #include <linux/interrupt.h> #include <linux/init.h> #include <linux/mm.h> #include <linux/notifier.h> #include <linux/percpu.h> #include <linux/cpu.h> |
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#include <linux/freezer.h> |
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#include <linux/kthread.h> #include <linux/rcupdate.h> |
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#include <linux/ftrace.h> |
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#include <linux/smp.h> |
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#include <linux/smpboot.h> |
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#include <linux/tick.h> |
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#include <linux/irq.h> |
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#define CREATE_TRACE_POINTS |
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#include <trace/events/irq.h> |
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|
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/* - No shared variables, all the data are CPU local. - If a softirq needs serialization, let it serialize itself by its own spinlocks. - Even if softirq is serialized, only local cpu is marked for execution. Hence, we get something sort of weak cpu binding. Though it is still not clear, will it result in better locality or will not. Examples: - NET RX softirq. It is multithreaded and does not require any global serialization. - NET TX softirq. It kicks software netdevice queues, hence it is logically serialized per device, but this serialization is invisible to common code. - Tasklets: serialized wrt itself. */ #ifndef __ARCH_IRQ_STAT |
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DEFINE_PER_CPU_ALIGNED(irq_cpustat_t, irq_stat); EXPORT_PER_CPU_SYMBOL(irq_stat); |
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#endif |
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static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp; |
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|
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DEFINE_PER_CPU(struct task_struct *, ksoftirqd); |
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|
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const char * const softirq_to_name[NR_SOFTIRQS] = { |
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"HI", "TIMER", "NET_TX", "NET_RX", "BLOCK", "IRQ_POLL", |
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"TASKLET", "SCHED", "HRTIMER", "RCU" |
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}; |
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/* * we cannot loop indefinitely here to avoid userspace starvation, * but we also don't want to introduce a worst case 1/HZ latency * to the pending events, so lets the scheduler to balance * the softirq load for us. */ |
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static void wakeup_softirqd(void) |
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{ /* Interrupts are disabled: no need to stop preemption */ |
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struct task_struct *tsk = __this_cpu_read(ksoftirqd); |
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if (tsk && tsk->state != TASK_RUNNING) wake_up_process(tsk); } /* |
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* If ksoftirqd is scheduled, we do not want to process pending softirqs |
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* right now. Let ksoftirqd handle this at its own rate, to get fairness, * unless we're doing some of the synchronous softirqs. |
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*/ |
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#define SOFTIRQ_NOW_MASK ((1 << HI_SOFTIRQ) | (1 << TASKLET_SOFTIRQ)) static bool ksoftirqd_running(unsigned long pending) |
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{ struct task_struct *tsk = __this_cpu_read(ksoftirqd); |
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if (pending & SOFTIRQ_NOW_MASK) return false; |
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return tsk && (tsk->state == TASK_RUNNING) && !__kthread_should_park(tsk); |
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} /* |
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* preempt_count and SOFTIRQ_OFFSET usage: * - preempt_count is changed by SOFTIRQ_OFFSET on entering or leaving * softirq processing. * - preempt_count is changed by SOFTIRQ_DISABLE_OFFSET (= 2 * SOFTIRQ_OFFSET) * on local_bh_disable or local_bh_enable. * This lets us distinguish between whether we are currently processing * softirq and whether we just have bh disabled. */ /* |
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* This one is for softirq.c-internal use, * where hardirqs are disabled legitimately: */ |
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#ifdef CONFIG_TRACE_IRQFLAGS |
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DEFINE_PER_CPU(int, hardirqs_enabled); DEFINE_PER_CPU(int, hardirq_context); EXPORT_PER_CPU_SYMBOL_GPL(hardirqs_enabled); EXPORT_PER_CPU_SYMBOL_GPL(hardirq_context); |
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void __local_bh_disable_ip(unsigned long ip, unsigned int cnt) |
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{ unsigned long flags; WARN_ON_ONCE(in_irq()); raw_local_irq_save(flags); |
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/* |
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* The preempt tracer hooks into preempt_count_add and will break |
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* lockdep because it calls back into lockdep after SOFTIRQ_OFFSET * is set and before current->softirq_enabled is cleared. * We must manually increment preempt_count here and manually * call the trace_preempt_off later. */ |
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__preempt_count_add(cnt); |
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/* * Were softirqs turned off above: */ |
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if (softirq_count() == (cnt & SOFTIRQ_MASK)) |
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lockdep_softirqs_off(ip); |
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raw_local_irq_restore(flags); |
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|
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if (preempt_count() == cnt) { #ifdef CONFIG_DEBUG_PREEMPT |
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current->preempt_disable_ip = get_lock_parent_ip(); |
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#endif |
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trace_preempt_off(CALLER_ADDR0, get_lock_parent_ip()); |
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} |
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} |
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EXPORT_SYMBOL(__local_bh_disable_ip); |
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#endif /* CONFIG_TRACE_IRQFLAGS */ |
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|
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static void __local_bh_enable(unsigned int cnt) { |
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lockdep_assert_irqs_disabled(); |
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|
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if (preempt_count() == cnt) trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip()); |
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if (softirq_count() == (cnt & SOFTIRQ_MASK)) |
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lockdep_softirqs_on(_RET_IP_); |
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__preempt_count_sub(cnt); |
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} |
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/* |
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* Special-case - softirqs can safely be enabled by __do_softirq(), |
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* without processing still-pending softirqs: */ void _local_bh_enable(void) { |
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WARN_ON_ONCE(in_irq()); |
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__local_bh_enable(SOFTIRQ_DISABLE_OFFSET); |
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} |
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EXPORT_SYMBOL(_local_bh_enable); |
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void __local_bh_enable_ip(unsigned long ip, unsigned int cnt) |
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{ |
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WARN_ON_ONCE(in_irq()); lockdep_assert_irqs_enabled(); |
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#ifdef CONFIG_TRACE_IRQFLAGS |
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local_irq_disable(); |
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#endif |
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/* * Are softirqs going to be turned on now: */ |
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if (softirq_count() == SOFTIRQ_DISABLE_OFFSET) |
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lockdep_softirqs_on(ip); |
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/* * Keep preemption disabled until we are done with * softirq processing: |
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*/ |
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preempt_count_sub(cnt - 1); |
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|
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if (unlikely(!in_interrupt() && local_softirq_pending())) { /* * Run softirq if any pending. And do it in its own stack * as we may be calling this deep in a task call stack already. */ |
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do_softirq(); |
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} |
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|
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preempt_count_dec(); |
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#ifdef CONFIG_TRACE_IRQFLAGS |
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local_irq_enable(); |
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#endif |
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preempt_check_resched(); } |
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EXPORT_SYMBOL(__local_bh_enable_ip); |
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/* |
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* We restart softirq processing for at most MAX_SOFTIRQ_RESTART times, * but break the loop if need_resched() is set or after 2 ms. * The MAX_SOFTIRQ_TIME provides a nice upper bound in most cases, but in * certain cases, such as stop_machine(), jiffies may cease to * increment and so we need the MAX_SOFTIRQ_RESTART limit as * well to make sure we eventually return from this method. |
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* |
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* These limits have been established via experimentation. |
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* The two things to balance is latency against fairness - * we want to handle softirqs as soon as possible, but they * should not be able to lock up the box. */ |
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#define MAX_SOFTIRQ_TIME msecs_to_jiffies(2) |
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#define MAX_SOFTIRQ_RESTART 10 |
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|
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#ifdef CONFIG_TRACE_IRQFLAGS /* |
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* When we run softirqs from irq_exit() and thus on the hardirq stack we need * to keep the lockdep irq context tracking as tight as possible in order to * not miss-qualify lock contexts and miss possible deadlocks. */ |
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|
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static inline bool lockdep_softirq_start(void) |
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{ |
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bool in_hardirq = false; |
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|
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if (lockdep_hardirq_context()) { |
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in_hardirq = true; |
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lockdep_hardirq_exit(); |
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} |
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lockdep_softirq_enter(); |
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return in_hardirq; |
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} |
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static inline void lockdep_softirq_end(bool in_hardirq) |
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{ lockdep_softirq_exit(); |
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if (in_hardirq) |
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lockdep_hardirq_enter(); |
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} |
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#else |
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static inline bool lockdep_softirq_start(void) { return false; } static inline void lockdep_softirq_end(bool in_hardirq) { } |
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#endif |
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asmlinkage __visible void __softirq_entry __do_softirq(void) |
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{ |
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unsigned long end = jiffies + MAX_SOFTIRQ_TIME; |
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unsigned long old_flags = current->flags; |
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int max_restart = MAX_SOFTIRQ_RESTART; |
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struct softirq_action *h; |
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bool in_hardirq; |
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__u32 pending; |
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int softirq_bit; |
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/* |
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* Mask out PF_MEMALLOC as the current task context is borrowed for the * softirq. A softirq handled, such as network RX, might set PF_MEMALLOC * again if the socket is related to swapping. |
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*/ current->flags &= ~PF_MEMALLOC; |
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pending = local_softirq_pending(); |
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account_irq_enter_time(current); |
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|
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__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET); |
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in_hardirq = lockdep_softirq_start(); |
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|
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restart: /* Reset the pending bitmask before enabling irqs */ |
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set_softirq_pending(0); |
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|
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local_irq_enable(); |
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h = softirq_vec; |
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while ((softirq_bit = ffs(pending))) { unsigned int vec_nr; int prev_count; h += softirq_bit - 1; vec_nr = h - softirq_vec; prev_count = preempt_count(); kstat_incr_softirqs_this_cpu(vec_nr); trace_softirq_entry(vec_nr); h->action(h); trace_softirq_exit(vec_nr); if (unlikely(prev_count != preempt_count())) { |
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pr_err("huh, entered softirq %u %s %p with preempt_count %08x, exited with %08x? ", |
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vec_nr, softirq_to_name[vec_nr], h->action, prev_count, preempt_count()); preempt_count_set(prev_count); |
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} h++; |
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pending >>= softirq_bit; } |
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|
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if (__this_cpu_read(ksoftirqd) == current) rcu_softirq_qs(); |
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local_irq_disable(); |
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pending = local_softirq_pending(); |
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if (pending) { |
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if (time_before(jiffies, end) && !need_resched() && --max_restart) |
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goto restart; |
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|
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wakeup_softirqd(); |
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} |
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|
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lockdep_softirq_end(in_hardirq); |
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account_irq_exit_time(current); |
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__local_bh_enable(SOFTIRQ_OFFSET); |
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WARN_ON_ONCE(in_interrupt()); |
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current_restore_flags(old_flags, PF_MEMALLOC); |
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} |
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asmlinkage __visible void do_softirq(void) |
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{ __u32 pending; unsigned long flags; if (in_interrupt()) return; local_irq_save(flags); pending = local_softirq_pending(); |
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if (pending && !ksoftirqd_running(pending)) |
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do_softirq_own_stack(); |
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local_irq_restore(flags); } |
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/** * irq_enter_rcu - Enter an interrupt context with RCU watching |
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*/ |
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void irq_enter_rcu(void) |
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{ |
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if (is_idle_task(current) && !in_interrupt()) { |
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/* * Prevent raise_softirq from needlessly waking up ksoftirqd * here, as softirq will be serviced on return from interrupt. */ local_bh_disable(); |
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tick_irq_enter(); |
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_local_bh_enable(); } |
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__irq_enter(); |
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} |
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/** * irq_enter - Enter an interrupt context including RCU update */ void irq_enter(void) { rcu_irq_enter(); irq_enter_rcu(); } |
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static inline void invoke_softirq(void) { |
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if (ksoftirqd_running(local_softirq_pending())) |
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return; |
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if (!force_irqthreads) { |
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#ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK |
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/* * We can safely execute softirq on the current stack if * it is the irq stack, because it should be near empty |
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* at this stage. */ __do_softirq(); #else /* * Otherwise, irq_exit() is called on the task stack that can * be potentially deep already. So call softirq in its own stack * to prevent from any overrun. |
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*/ |
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do_softirq_own_stack(); |
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#endif |
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} else { |
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wakeup_softirqd(); |
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} |
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} |
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|
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static inline void tick_irq_exit(void) { #ifdef CONFIG_NO_HZ_COMMON int cpu = smp_processor_id(); /* Make sure that timer wheel updates are propagated */ if ((idle_cpu(cpu) && !need_resched()) || tick_nohz_full_cpu(cpu)) { |
0a0e0829f nohz: Fix missing... |
389 |
if (!in_irq()) |
67826eae8 nohz: Disable the... |
390 391 392 393 |
tick_nohz_irq_exit(); } #endif } |
59bc300b7 x86/entry: Clarif... |
394 |
static inline void __irq_exit_rcu(void) |
1da177e4c Linux-2.6.12-rc2 |
395 |
{ |
74eed0163 irq: Ensure irq_e... |
396 |
#ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED |
4cd5d1115 irq: Don't re-ena... |
397 |
local_irq_disable(); |
74eed0163 irq: Ensure irq_e... |
398 |
#else |
f71b74bca irq/softirqs: Use... |
399 |
lockdep_assert_irqs_disabled(); |
74eed0163 irq: Ensure irq_e... |
400 |
#endif |
6a61671bb cputime: Safely r... |
401 |
account_irq_exit_time(current); |
bdb438065 sched: Extract th... |
402 |
preempt_count_sub(HARDIRQ_OFFSET); |
1da177e4c Linux-2.6.12-rc2 |
403 404 |
if (!in_interrupt() && local_softirq_pending()) invoke_softirq(); |
79bf2bb33 [PATCH] tick-mana... |
405 |
|
67826eae8 nohz: Disable the... |
406 |
tick_irq_exit(); |
8a6bc4787 genirq: Provide i... |
407 408 409 |
} /** |
59bc300b7 x86/entry: Clarif... |
410 411 412 413 414 415 416 417 418 419 420 421 |
* irq_exit_rcu() - Exit an interrupt context without updating RCU * * Also processes softirqs if needed and possible. */ void irq_exit_rcu(void) { __irq_exit_rcu(); /* must be last! */ lockdep_hardirq_exit(); } /** |
8a6bc4787 genirq: Provide i... |
422 423 424 425 426 427 |
* irq_exit - Exit an interrupt context, update RCU and lockdep * * Also processes softirqs if needed and possible. */ void irq_exit(void) { |
59bc300b7 x86/entry: Clarif... |
428 |
__irq_exit_rcu(); |
416eb33cd rcu: Fix early ca... |
429 |
rcu_irq_exit(); |
2502ec37a lockdep: Rename t... |
430 431 |
/* must be last! */ lockdep_hardirq_exit(); |
1da177e4c Linux-2.6.12-rc2 |
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} /* * This function must run with irqs disabled! */ |
7ad5b3a50 kernel: remove fa... |
437 |
inline void raise_softirq_irqoff(unsigned int nr) |
1da177e4c Linux-2.6.12-rc2 |
438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 |
{ __raise_softirq_irqoff(nr); /* * If we're in an interrupt or softirq, we're done * (this also catches softirq-disabled code). We will * actually run the softirq once we return from * the irq or softirq. * * Otherwise we wake up ksoftirqd to make sure we * schedule the softirq soon. */ if (!in_interrupt()) wakeup_softirqd(); } |
7ad5b3a50 kernel: remove fa... |
453 |
void raise_softirq(unsigned int nr) |
1da177e4c Linux-2.6.12-rc2 |
454 455 456 457 458 459 460 |
{ unsigned long flags; local_irq_save(flags); raise_softirq_irqoff(nr); local_irq_restore(flags); } |
f069686e4 tracing/softirq: ... |
461 462 |
void __raise_softirq_irqoff(unsigned int nr) { |
cdabce2e3 softirq: Add debu... |
463 |
lockdep_assert_irqs_disabled(); |
f069686e4 tracing/softirq: ... |
464 465 466 |
trace_softirq_raise(nr); or_softirq_pending(1UL << nr); } |
962cf36c5 Remove argument f... |
467 |
void open_softirq(int nr, void (*action)(struct softirq_action *)) |
1da177e4c Linux-2.6.12-rc2 |
468 |
{ |
1da177e4c Linux-2.6.12-rc2 |
469 470 |
softirq_vec[nr].action = action; } |
9ba5f005c softirq: introduc... |
471 472 473 |
/* * Tasklets */ |
ce85b4f2e softirq: use cons... |
474 |
struct tasklet_head { |
48f20a9a9 tasklets: execute... |
475 476 |
struct tasklet_struct *head; struct tasklet_struct **tail; |
1da177e4c Linux-2.6.12-rc2 |
477 |
}; |
4620b49f7 softirq: remove i... |
478 479 |
static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec); static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec); |
1da177e4c Linux-2.6.12-rc2 |
480 |
|
6498ddad3 softirq: Consolid... |
481 482 483 |
static void __tasklet_schedule_common(struct tasklet_struct *t, struct tasklet_head __percpu *headp, unsigned int softirq_nr) |
1da177e4c Linux-2.6.12-rc2 |
484 |
{ |
6498ddad3 softirq: Consolid... |
485 |
struct tasklet_head *head; |
1da177e4c Linux-2.6.12-rc2 |
486 487 488 |
unsigned long flags; local_irq_save(flags); |
6498ddad3 softirq: Consolid... |
489 |
head = this_cpu_ptr(headp); |
48f20a9a9 tasklets: execute... |
490 |
t->next = NULL; |
6498ddad3 softirq: Consolid... |
491 492 493 |
*head->tail = t; head->tail = &(t->next); raise_softirq_irqoff(softirq_nr); |
1da177e4c Linux-2.6.12-rc2 |
494 495 |
local_irq_restore(flags); } |
6498ddad3 softirq: Consolid... |
496 497 498 499 500 501 |
void __tasklet_schedule(struct tasklet_struct *t) { __tasklet_schedule_common(t, &tasklet_vec, TASKLET_SOFTIRQ); } |
1da177e4c Linux-2.6.12-rc2 |
502 |
EXPORT_SYMBOL(__tasklet_schedule); |
7ad5b3a50 kernel: remove fa... |
503 |
void __tasklet_hi_schedule(struct tasklet_struct *t) |
1da177e4c Linux-2.6.12-rc2 |
504 |
{ |
6498ddad3 softirq: Consolid... |
505 506 |
__tasklet_schedule_common(t, &tasklet_hi_vec, HI_SOFTIRQ); |
1da177e4c Linux-2.6.12-rc2 |
507 |
} |
1da177e4c Linux-2.6.12-rc2 |
508 |
EXPORT_SYMBOL(__tasklet_hi_schedule); |
82b691bed softirq: Consolid... |
509 510 511 |
static void tasklet_action_common(struct softirq_action *a, struct tasklet_head *tl_head, unsigned int softirq_nr) |
1da177e4c Linux-2.6.12-rc2 |
512 513 514 515 |
{ struct tasklet_struct *list; local_irq_disable(); |
82b691bed softirq: Consolid... |
516 517 518 |
list = tl_head->head; tl_head->head = NULL; tl_head->tail = &tl_head->head; |
1da177e4c Linux-2.6.12-rc2 |
519 520 521 522 523 524 525 526 527 |
local_irq_enable(); while (list) { struct tasklet_struct *t = list; list = list->next; if (tasklet_trylock(t)) { if (!atomic_read(&t->count)) { |
ce85b4f2e softirq: use cons... |
528 529 |
if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) |
1da177e4c Linux-2.6.12-rc2 |
530 |
BUG(); |
12cc923f1 tasklet: Introduc... |
531 532 533 534 |
if (t->use_callback) t->callback(t); else t->func(t->data); |
1da177e4c Linux-2.6.12-rc2 |
535 536 537 538 539 540 541 |
tasklet_unlock(t); continue; } tasklet_unlock(t); } local_irq_disable(); |
48f20a9a9 tasklets: execute... |
542 |
t->next = NULL; |
82b691bed softirq: Consolid... |
543 544 545 |
*tl_head->tail = t; tl_head->tail = &t->next; __raise_softirq_irqoff(softirq_nr); |
1da177e4c Linux-2.6.12-rc2 |
546 547 548 |
local_irq_enable(); } } |
82b691bed softirq: Consolid... |
549 |
static __latent_entropy void tasklet_action(struct softirq_action *a) |
1da177e4c Linux-2.6.12-rc2 |
550 |
{ |
82b691bed softirq: Consolid... |
551 552 |
tasklet_action_common(a, this_cpu_ptr(&tasklet_vec), TASKLET_SOFTIRQ); } |
1da177e4c Linux-2.6.12-rc2 |
553 |
|
82b691bed softirq: Consolid... |
554 555 556 |
static __latent_entropy void tasklet_hi_action(struct softirq_action *a) { tasklet_action_common(a, this_cpu_ptr(&tasklet_hi_vec), HI_SOFTIRQ); |
1da177e4c Linux-2.6.12-rc2 |
557 |
} |
12cc923f1 tasklet: Introduc... |
558 559 560 561 562 563 564 565 566 567 568 |
void tasklet_setup(struct tasklet_struct *t, void (*callback)(struct tasklet_struct *)) { t->next = NULL; t->state = 0; atomic_set(&t->count, 0); t->callback = callback; t->use_callback = true; t->data = 0; } EXPORT_SYMBOL(tasklet_setup); |
1da177e4c Linux-2.6.12-rc2 |
569 570 571 572 573 574 575 |
void tasklet_init(struct tasklet_struct *t, void (*func)(unsigned long), unsigned long data) { t->next = NULL; t->state = 0; atomic_set(&t->count, 0); t->func = func; |
12cc923f1 tasklet: Introduc... |
576 |
t->use_callback = false; |
1da177e4c Linux-2.6.12-rc2 |
577 578 |
t->data = data; } |
1da177e4c Linux-2.6.12-rc2 |
579 580 581 582 583 |
EXPORT_SYMBOL(tasklet_init); void tasklet_kill(struct tasklet_struct *t) { if (in_interrupt()) |
403227641 softirq: convert ... |
584 585 |
pr_notice("Attempt to kill tasklet from interrupt "); |
1da177e4c Linux-2.6.12-rc2 |
586 587 |
while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) { |
79d381c9f kernel/softirq.c:... |
588 |
do { |
1da177e4c Linux-2.6.12-rc2 |
589 |
yield(); |
79d381c9f kernel/softirq.c:... |
590 |
} while (test_bit(TASKLET_STATE_SCHED, &t->state)); |
1da177e4c Linux-2.6.12-rc2 |
591 592 593 594 |
} tasklet_unlock_wait(t); clear_bit(TASKLET_STATE_SCHED, &t->state); } |
1da177e4c Linux-2.6.12-rc2 |
595 596 597 598 |
EXPORT_SYMBOL(tasklet_kill); void __init softirq_init(void) { |
48f20a9a9 tasklets: execute... |
599 600 601 602 603 604 605 606 |
int cpu; for_each_possible_cpu(cpu) { per_cpu(tasklet_vec, cpu).tail = &per_cpu(tasklet_vec, cpu).head; per_cpu(tasklet_hi_vec, cpu).tail = &per_cpu(tasklet_hi_vec, cpu).head; } |
962cf36c5 Remove argument f... |
607 608 |
open_softirq(TASKLET_SOFTIRQ, tasklet_action); open_softirq(HI_SOFTIRQ, tasklet_hi_action); |
1da177e4c Linux-2.6.12-rc2 |
609 |
} |
3e339b5da softirq: Use hotp... |
610 |
static int ksoftirqd_should_run(unsigned int cpu) |
1da177e4c Linux-2.6.12-rc2 |
611 |
{ |
3e339b5da softirq: Use hotp... |
612 613 |
return local_softirq_pending(); } |
1da177e4c Linux-2.6.12-rc2 |
614 |
|
3e339b5da softirq: Use hotp... |
615 616 617 618 |
static void run_ksoftirqd(unsigned int cpu) { local_irq_disable(); if (local_softirq_pending()) { |
0bed698a3 irq: Justify the ... |
619 620 621 622 |
/* * We can safely run softirq on inline stack, as we are not deep * in the task stack here. */ |
3e339b5da softirq: Use hotp... |
623 |
__do_softirq(); |
3e339b5da softirq: Use hotp... |
624 |
local_irq_enable(); |
edf22f4ca softirq: Eliminat... |
625 |
cond_resched(); |
3e339b5da softirq: Use hotp... |
626 |
return; |
1da177e4c Linux-2.6.12-rc2 |
627 |
} |
3e339b5da softirq: Use hotp... |
628 |
local_irq_enable(); |
1da177e4c Linux-2.6.12-rc2 |
629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 |
} #ifdef CONFIG_HOTPLUG_CPU /* * tasklet_kill_immediate is called to remove a tasklet which can already be * scheduled for execution on @cpu. * * Unlike tasklet_kill, this function removes the tasklet * _immediately_, even if the tasklet is in TASKLET_STATE_SCHED state. * * When this function is called, @cpu must be in the CPU_DEAD state. */ void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu) { struct tasklet_struct **i; BUG_ON(cpu_online(cpu)); BUG_ON(test_bit(TASKLET_STATE_RUN, &t->state)); if (!test_bit(TASKLET_STATE_SCHED, &t->state)) return; /* CPU is dead, so no lock needed. */ |
48f20a9a9 tasklets: execute... |
652 |
for (i = &per_cpu(tasklet_vec, cpu).head; *i; i = &(*i)->next) { |
1da177e4c Linux-2.6.12-rc2 |
653 654 |
if (*i == t) { *i = t->next; |
48f20a9a9 tasklets: execute... |
655 656 657 |
/* If this was the tail element, move the tail ptr */ if (*i == NULL) per_cpu(tasklet_vec, cpu).tail = i; |
1da177e4c Linux-2.6.12-rc2 |
658 659 660 661 662 |
return; } } BUG(); } |
c4544dbc7 kernel/softirq: C... |
663 |
static int takeover_tasklets(unsigned int cpu) |
1da177e4c Linux-2.6.12-rc2 |
664 |
{ |
1da177e4c Linux-2.6.12-rc2 |
665 666 667 668 |
/* CPU is dead, so no lock needed. */ local_irq_disable(); /* Find end, append list for that CPU. */ |
e5e417232 Fix cpu hotplug p... |
669 |
if (&per_cpu(tasklet_vec, cpu).head != per_cpu(tasklet_vec, cpu).tail) { |
909ea9646 core: Replace __g... |
670 |
*__this_cpu_read(tasklet_vec.tail) = per_cpu(tasklet_vec, cpu).head; |
8afecaa68 softirq: Use __th... |
671 |
__this_cpu_write(tasklet_vec.tail, per_cpu(tasklet_vec, cpu).tail); |
e5e417232 Fix cpu hotplug p... |
672 673 674 |
per_cpu(tasklet_vec, cpu).head = NULL; per_cpu(tasklet_vec, cpu).tail = &per_cpu(tasklet_vec, cpu).head; } |
1da177e4c Linux-2.6.12-rc2 |
675 |
raise_softirq_irqoff(TASKLET_SOFTIRQ); |
e5e417232 Fix cpu hotplug p... |
676 |
if (&per_cpu(tasklet_hi_vec, cpu).head != per_cpu(tasklet_hi_vec, cpu).tail) { |
909ea9646 core: Replace __g... |
677 678 |
*__this_cpu_read(tasklet_hi_vec.tail) = per_cpu(tasklet_hi_vec, cpu).head; __this_cpu_write(tasklet_hi_vec.tail, per_cpu(tasklet_hi_vec, cpu).tail); |
e5e417232 Fix cpu hotplug p... |
679 680 681 |
per_cpu(tasklet_hi_vec, cpu).head = NULL; per_cpu(tasklet_hi_vec, cpu).tail = &per_cpu(tasklet_hi_vec, cpu).head; } |
1da177e4c Linux-2.6.12-rc2 |
682 683 684 |
raise_softirq_irqoff(HI_SOFTIRQ); local_irq_enable(); |
c4544dbc7 kernel/softirq: C... |
685 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
686 |
} |
c4544dbc7 kernel/softirq: C... |
687 688 |
#else #define takeover_tasklets NULL |
1da177e4c Linux-2.6.12-rc2 |
689 |
#endif /* CONFIG_HOTPLUG_CPU */ |
3e339b5da softirq: Use hotp... |
690 691 692 693 694 695 |
static struct smp_hotplug_thread softirq_threads = { .store = &ksoftirqd, .thread_should_run = ksoftirqd_should_run, .thread_fn = run_ksoftirqd, .thread_comm = "ksoftirqd/%u", }; |
7babe8db9 Full conversion t... |
696 |
static __init int spawn_ksoftirqd(void) |
1da177e4c Linux-2.6.12-rc2 |
697 |
{ |
c4544dbc7 kernel/softirq: C... |
698 699 |
cpuhp_setup_state_nocalls(CPUHP_SOFTIRQ_DEAD, "softirq:dead", NULL, takeover_tasklets); |
3e339b5da softirq: Use hotp... |
700 |
BUG_ON(smpboot_register_percpu_thread(&softirq_threads)); |
1da177e4c Linux-2.6.12-rc2 |
701 702 |
return 0; } |
7babe8db9 Full conversion t... |
703 |
early_initcall(spawn_ksoftirqd); |
78eef01b0 [PATCH] on_each_c... |
704 |
|
43a256322 sparseirq: move _... |
705 706 707 708 709 710 711 712 713 |
/* * [ These __weak aliases are kept in a separate compilation unit, so that * GCC does not inline them incorrectly. ] */ int __init __weak early_irq_init(void) { return 0; } |
4a046d175 x86: arch_probe_n... |
714 715 |
int __init __weak arch_probe_nr_irqs(void) { |
b683de2b3 genirq: Query arc... |
716 |
return NR_IRQS_LEGACY; |
4a046d175 x86: arch_probe_n... |
717 |
} |
43a256322 sparseirq: move _... |
718 719 720 721 |
int __init __weak arch_early_irq_init(void) { return 0; } |
62a08ae2a genirq: x86: Ensu... |
722 723 724 725 726 |
unsigned int __weak arch_dynirq_lower_bound(unsigned int from) { return from; } |