在linux内核中使用stop_sched_class有什么用处

#define for_each_class(class) 
   for (class = sched_class_highest; class; class = class->next)


#define sched_class_highest (&stop_sched_class)
extern const struct sched_class stop_sched_class;

/*
 * Simple,special scheduling class for the per-CPU stop tasks:
*/
const struct sched_class stop_sched_class = {
   .next                   = &rt_sched_class,.enqueue_task           = enqueue_task_stop,.dequeue_task           = dequeue_task_stop,.yield_task             = yield_task_stop,.check_preempt_curr     = check_preempt_curr_stop,.pick_next_task         = pick_next_task_stop,.put_prev_task          = put_prev_task_stop,#ifdef CONFIG_SMP
   .select_task_rq         = select_task_rq_stop,#endif

  .set_curr_task          = set_curr_task_stop,.task_tick              = task_tick_stop,.get_rr_interval        = get_rr_interval_stop,.prio_changed           = prio_changed_stop,.switched_to            = switched_to_stop,};