sched: fix bug in balance_tasks()
[linux-2.6.git] / kernel / sched_idletask.c
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  */
11 static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p)
12 {
13         resched_task(rq->idle);
14 }
15
16 static struct task_struct *pick_next_task_idle(struct rq *rq, u64 now)
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  */
27 static void
28 dequeue_task_idle(struct rq *rq, struct task_struct *p, int sleep, u64 now)
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
36 static void put_prev_task_idle(struct rq *rq, struct task_struct *prev, u64 now)
37 {
38 }
39
40 static unsigned long
41 load_balance_idle(struct rq *this_rq, int this_cpu, struct rq *busiest,
42                         unsigned long max_nr_move, unsigned long max_load_move,
43                         struct sched_domain *sd, enum cpu_idle_type idle,
44                         int *all_pinned, int *this_best_prio)
45 {
46         return 0;
47 }
48
49 static void task_tick_idle(struct rq *rq, struct task_struct *curr)
50 {
51 }
52
53 /*
54  * Simple, special scheduling class for the per-CPU idle tasks:
55  */
56 static struct sched_class idle_sched_class __read_mostly = {
57         /* no enqueue/yield_task for idle tasks */
58
59         /* dequeue is not valid, we print a debug message there: */
60         .dequeue_task           = dequeue_task_idle,
61
62         .check_preempt_curr     = check_preempt_curr_idle,
63
64         .pick_next_task         = pick_next_task_idle,
65         .put_prev_task          = put_prev_task_idle,
66
67         .load_balance           = load_balance_idle,
68
69         .task_tick              = task_tick_idle,
70         /* no .task_new for idle tasks */
71 };