Git Repo - linux.git/blame_incremental - kernel/sched

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Commit	Line	Data
	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	#ifdef CONFIG_SMP
	9	static int select_task_rq_idle(struct task_struct *p, int sync)
	10	{
	11	return task_cpu(p); /* IDLE tasks as never migrated */
	12	}
	13	#endif /* CONFIG_SMP */
	14	/*
	15	* Idle tasks are unconditionally rescheduled:
	16	*/
	17	static void check_preempt_curr_idle(struct rq rq, struct task_struct p, int sync)
	18	{
	19	resched_task(rq->idle);
	20	}
	21
	22	static struct task_struct pick_next_task_idle(struct rq rq)
	23	{
	24	schedstat_inc(rq, sched_goidle);
	25	/* adjust the active tasks as we might go into a long sleep */
	26	calc_load_account_active(rq);
	27	return rq->idle;
	28	}
	29
	30	/*
	31	* It is not legal to sleep in the idle task - print a warning
	32	* message if some code attempts to do it:
	33	*/
	34	static void
	35	dequeue_task_idle(struct rq rq, struct task_struct p, int sleep)
	36	{
	37	spin_unlock_irq(&rq->lock);
	38	printk(KERN_ERR "bad: scheduling from the idle thread!\n");
	39	dump_stack();
	40	spin_lock_irq(&rq->lock);
	41	}
	42
	43	static void put_prev_task_idle(struct rq rq, struct task_struct prev)
	44	{
	45	}
	46
	47	#ifdef CONFIG_SMP
	48	static unsigned long
	49	load_balance_idle(struct rq this_rq, int this_cpu, struct rq busiest,
	50	unsigned long max_load_move,
	51	struct sched_domain *sd, enum cpu_idle_type idle,
	52	int all_pinned, int this_best_prio)
	53	{
	54	return 0;
	55	}
	56
	57	static int
	58	move_one_task_idle(struct rq this_rq, int this_cpu, struct rq busiest,
	59	struct sched_domain *sd, enum cpu_idle_type idle)
	60	{
	61	return 0;
	62	}
	63	#endif
	64
	65	static void task_tick_idle(struct rq rq, struct task_struct curr, int queued)
	66	{
	67	}
	68
	69	static void set_curr_task_idle(struct rq *rq)
	70	{
	71	}
	72
	73	static void switched_to_idle(struct rq rq, struct task_struct p,
	74	int running)
	75	{
	76	/* Can this actually happen?? */
	77	if (running)
	78	resched_task(rq->curr);
	79	else
	80	check_preempt_curr(rq, p, 0);
	81	}
	82
	83	static void prio_changed_idle(struct rq rq, struct task_struct p,
	84	int oldprio, int running)
	85	{
	86	/* This can happen for hot plug CPUS */
	87
	88	/*
	89	* Reschedule if we are currently running on this runqueue and
	90	* our priority decreased, or if we are not currently running on
	91	* this runqueue and our priority is higher than the current's
	92	*/
	93	if (running) {
	94	if (p->prio > oldprio)
	95	resched_task(rq->curr);
	96	} else
	97	check_preempt_curr(rq, p, 0);
	98	}
	99
	100	/*
	101	* Simple, special scheduling class for the per-CPU idle tasks:
	102	*/
	103	static const struct sched_class idle_sched_class = {
	104	/* .next is NULL */
	105	/* no enqueue/yield_task for idle tasks */
	106
	107	/* dequeue is not valid, we print a debug message there: */
	108	.dequeue_task = dequeue_task_idle,
	109
	110	.check_preempt_curr = check_preempt_curr_idle,
	111
	112	.pick_next_task = pick_next_task_idle,
	113	.put_prev_task = put_prev_task_idle,
	114
	115	#ifdef CONFIG_SMP
	116	.select_task_rq = select_task_rq_idle,
	117
	118	.load_balance = load_balance_idle,
	119	.move_one_task = move_one_task_idle,
	120	#endif
	121
	122	.set_curr_task = set_curr_task_idle,
	123	.task_tick = task_tick_idle,
	124
	125	.prio_changed = prio_changed_idle,
	126	.switched_to = switched_to_idle,
	127
	128	/* no .task_new for idle tasks */
	129	};