简介

内核中断的下半部分提供了好几种机制。

• 软中断
• tasklet
  • 小任务机制
• 
  

软中断

内核实现了10种软中断。

Linux-4.9.88/include/linux/interrupt.h
enum
{
    HI_SOFTIRQ=0,
    TIMER_SOFTIRQ,
    NET_TX_SOFTIRQ,
    NET_RX_SOFTIRQ,
    BLOCK_SOFTIRQ,
    IRQ_POLL_SOFTIRQ,
    TASKLET_SOFTIRQ,
    SCHED_SOFTIRQ,
    HRTIMER_SOFTIRQ, /* Unused, but kept as tools rely on the
                numbering. Sigh! */
    RCU_SOFTIRQ,    /* Preferable RCU should always be the last softirq */
    NR_SOFTIRQS
};

tasklet

小任务机制是I/O驱动程序中的实现可延迟函数的首选。