2 * idle-task scheduling class.
4 * (NOTE: these are not related to SCHED_IDLE tasks which are
5 * handled in sched_fair.c)
10 select_task_rq_idle(struct rq *rq, struct task_struct *p, int sd_flag, int flags)
12 return task_cpu(p); /* IDLE tasks as never migrated */
14 #endif /* CONFIG_SMP */
16 * Idle tasks are unconditionally rescheduled:
18 static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int flags)
20 resched_task(rq->idle);
23 static struct task_struct *pick_next_task_idle(struct rq *rq)
25 schedstat_inc(rq, sched_goidle);
26 /* adjust the active tasks as we might go into a long sleep */
27 calc_load_account_active(rq);
32 * It is not legal to sleep in the idle task - print a warning
33 * message if some code attempts to do it:
36 dequeue_task_idle(struct rq *rq, struct task_struct *p, int sleep)
38 spin_unlock_irq(&rq->lock);
39 printk(KERN_ERR "bad: scheduling from the idle thread!\n");
41 spin_lock_irq(&rq->lock);
44 static void put_prev_task_idle(struct rq *rq, struct task_struct *prev)
50 load_balance_idle(struct rq *this_rq, int this_cpu, struct rq *busiest,
51 unsigned long max_load_move,
52 struct sched_domain *sd, enum cpu_idle_type idle,
53 int *all_pinned, int *this_best_prio)
59 move_one_task_idle(struct rq *this_rq, int this_cpu, struct rq *busiest,
60 struct sched_domain *sd, enum cpu_idle_type idle)
66 static void task_tick_idle(struct rq *rq, struct task_struct *curr, int queued)
70 static void set_curr_task_idle(struct rq *rq)
74 static void switched_to_idle(struct rq *rq, struct task_struct *p,
77 /* Can this actually happen?? */
79 resched_task(rq->curr);
81 check_preempt_curr(rq, p, 0);
84 static void prio_changed_idle(struct rq *rq, struct task_struct *p,
85 int oldprio, int running)
87 /* This can happen for hot plug CPUS */
90 * Reschedule if we are currently running on this runqueue and
91 * our priority decreased, or if we are not currently running on
92 * this runqueue and our priority is higher than the current's
95 if (p->prio > oldprio)
96 resched_task(rq->curr);
98 check_preempt_curr(rq, p, 0);
101 unsigned int get_rr_interval_idle(struct rq *rq, struct task_struct *task)
107 * Simple, special scheduling class for the per-CPU idle tasks:
109 static const struct sched_class idle_sched_class = {
111 /* no enqueue/yield_task for idle tasks */
113 /* dequeue is not valid, we print a debug message there: */
114 .dequeue_task = dequeue_task_idle,
116 .check_preempt_curr = check_preempt_curr_idle,
118 .pick_next_task = pick_next_task_idle,
119 .put_prev_task = put_prev_task_idle,
122 .select_task_rq = select_task_rq_idle,
124 .load_balance = load_balance_idle,
125 .move_one_task = move_one_task_idle,
128 .set_curr_task = set_curr_task_idle,
129 .task_tick = task_tick_idle,
131 .get_rr_interval = get_rr_interval_idle,
133 .prio_changed = prio_changed_idle,
134 .switched_to = switched_to_idle,
136 /* no .task_new for idle tasks */