1/* 2 * idle-task scheduling class. 3 * 4 * (NOTE: these are not related to SCHED_IDLE tasks which are 5 * handled in sched_fair.c) 6 */ 7 8/* 9 * Idle tasks are unconditionally rescheduled: 10 */ 11static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p) 12{ 13 resched_task(rq->idle); 14} 15 16static struct task_struct *pick_next_task_idle(struct rq *rq) 17{ 18 schedstat_inc(rq, sched_goidle); 19 20 return rq->idle; 21} 22 23/* 24 * It is not legal to sleep in the idle task - print a warning 25 * message if some code attempts to do it: 26 */ 27static void 28dequeue_task_idle(struct rq *rq, struct task_struct *p, int sleep) 29{ 30 spin_unlock_irq(&rq->lock); 31 printk(KERN_ERR "bad: scheduling from the idle thread!\n"); 32 dump_stack(); 33 spin_lock_irq(&rq->lock); 34} 35 36static void put_prev_task_idle(struct rq *rq, struct task_struct *prev) 37{ 38} 39 40#ifdef CONFIG_SMP 41static unsigned long 42load_balance_idle(struct rq *this_rq, int this_cpu, struct rq *busiest, 43 unsigned long max_load_move, 44 struct sched_domain *sd, enum cpu_idle_type idle, 45 int *all_pinned, int *this_best_prio) 46{ 47 return 0; 48} 49 50static int 51move_one_task_idle(struct rq *this_rq, int this_cpu, struct rq *busiest, 52 struct sched_domain *sd, enum cpu_idle_type idle) 53{ 54 return 0; 55} 56#endif 57 58static void task_tick_idle(struct rq *rq, struct task_struct *curr) 59{ 60} 61 62static void set_curr_task_idle(struct rq *rq) 63{ 64} 65 66/* 67 * Simple, special scheduling class for the per-CPU idle tasks: 68 */ 69const struct sched_class idle_sched_class = { 70 /* .next is NULL */ 71 /* no enqueue/yield_task for idle tasks */ 72 73 /* dequeue is not valid, we print a debug message there: */ 74 .dequeue_task = dequeue_task_idle, 75 76 .check_preempt_curr = check_preempt_curr_idle, 77 78 .pick_next_task = pick_next_task_idle, 79 .put_prev_task = put_prev_task_idle, 80 81#ifdef CONFIG_SMP 82 .load_balance = load_balance_idle, 83 .move_one_task = move_one_task_idle, 84#endif 85 86 .set_curr_task = set_curr_task_idle, 87 .task_tick = task_tick_idle, 88 /* no .task_new for idle tasks */ 89}; 90