deactivate_task 详解

 KERNEL_VERSION:linux-2.6.34

deactivate_task() ----remove a task from the run queue

static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
{

/* check if p->state is uninterruptible */
    if (task_contributes_to_load(p))
        rq->nr_uninterruptible++;


/* it will call dequeue_task in specific schedule class */
    dequeue_task(rq, p, sleep);

/* rq->nr_running-- */
    dec_nr_running(rq);
}

---

dequeue_task --- called by deactivate_task

static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
{
    if (sleep) {

/* current task had been wake up last time */
        if (p->se.last_wakeup) {
            update_avg(&p->se.avg_overlap,
                p->se.sum_exec_runtime - p->se.last_wakeup);
            p->se.last_wakeup = 0;
        } else {
            update_avg(&p->se.avg_wakeup,
                sysctl_sched_wakeup_granularity);
        }
    }

    sched_info_dequeued(p);
    p->sched_class->dequeue_task(rq, p, sleep);
    p->se.on_rq = 0;
}