软中断的调度

#ifndef local_softirq_pending_ref
#define local_softirq_pending_ref irq_stat.__softirq_pending  //软中断挂起位图，每bit代表一种软中断
#endif

#define local_softirq_pending()	(__this_cpu_read(local_softirq_pending_ref))
#define set_softirq_pending(x)	(__this_cpu_write(local_softirq_pending_ref, (x)))
#define or_softirq_pending(x)	(__this_cpu_or(local_softirq_pending_ref, (x)))

/*
 * This function must run with irqs disabled!
 */
inline void raise_softirq_irqoff(unsigned int nr)
{
    __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.
     */
    //检查当前是否不在中断或软中断上下文中, 如果当前在硬中断或软中断上下文中，软中断处理程序会在返回中断时自动执行，
    //无需额外处理。如果当前不在中断上下文中，需要主动唤醒 ksoftirqd，确保软中断被及时处理。
    if (!in_interrupt() && should_wake_ksoftirqd())
        wakeup_softirqd();
}

void raise_softirq(unsigned int nr)
{
    unsigned long flags;

    local_irq_save(flags);
    raise_softirq_irqoff(nr);
    local_irq_restore(flags);
}

// 禁用中毒的场景下设置软中断
void __raise_softirq_irqoff(unsigned int nr)
{
    lockdep_assert_irqs_disabled();
    trace_softirq_raise(nr);
    or_softirq_pending(1UL << nr);
}