FreeBSD 5 内核源代码分析之中断处理(5)

          swi_sched(softclock_ih, 0);

       ......
    }

    /*
     * Schedule a heavyweight software interrupt process.
     */
    void
    swi_sched(void *cookie, int flags)
    {
       struct intrhand *ih = (struct intrhand *)cookie;
       struct ithd *it = ih->ih_ithread;
       int error;

       atomic_add_int(&cnt.v_intr, 1); /* one more global interrupt */

       CTR3(KTR_INTR, "swi_sched pid %d(%s) need=%d",
          it->it_td->td_proc->p_pid, it->it_td->td_proc->p_comm, it->it_need);

       /*
        * Set ih_need for this handler so that if the ithread is already
        * running it will execute this handler on the next pass.  Otherwise,
        * it will execute it the next time it runs.
 &n