ALSA: ice1724 - Fix ESI Maya44 capture source control
[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 #ifdef CONFIG_SMP
9 static int select_task_rq_idle(struct task_struct *p, int sd_flag, int flags)
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 flags)
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         raw_spin_unlock_irq(&rq->lock);
38         printk(KERN_ERR "bad: scheduling from the idle thread!\n");
39         dump_stack();
40         raw_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 static void task_tick_idle(struct rq *rq, struct task_struct *curr, int queued)
48 {
49 }
50
51 static void set_curr_task_idle(struct rq *rq)
52 {
53 }
54
55 static void switched_to_idle(struct rq *rq, struct task_struct *p,
56                              int running)
57 {
58         /* Can this actually happen?? */
59         if (running)
60                 resched_task(rq->curr);
61         else
62                 check_preempt_curr(rq, p, 0);
63 }
64
65 static void prio_changed_idle(struct rq *rq, struct task_struct *p,
66                               int oldprio, int running)
67 {
68         /* This can happen for hot plug CPUS */
69
70         /*
71          * Reschedule if we are currently running on this runqueue and
72          * our priority decreased, or if we are not currently running on
73          * this runqueue and our priority is higher than the current's
74          */
75         if (running) {
76                 if (p->prio > oldprio)
77                         resched_task(rq->curr);
78         } else
79                 check_preempt_curr(rq, p, 0);
80 }
81
82 static unsigned int get_rr_interval_idle(struct rq *rq, struct task_struct *task)
83 {
84         return 0;
85 }
86
87 /*
88  * Simple, special scheduling class for the per-CPU idle tasks:
89  */
90 static const struct sched_class idle_sched_class = {
91         /* .next is NULL */
92         /* no enqueue/yield_task for idle tasks */
93
94         /* dequeue is not valid, we print a debug message there: */
95         .dequeue_task           = dequeue_task_idle,
96
97         .check_preempt_curr     = check_preempt_curr_idle,
98
99         .pick_next_task         = pick_next_task_idle,
100         .put_prev_task          = put_prev_task_idle,
101
102 #ifdef CONFIG_SMP
103         .select_task_rq         = select_task_rq_idle,
104 #endif
105
106         .set_curr_task          = set_curr_task_idle,
107         .task_tick              = task_tick_idle,
108
109         .get_rr_interval        = get_rr_interval_idle,
110
111         .prio_changed           = prio_changed_idle,
112         .switched_to            = switched_to_idle,
113
114         /* no .task_new for idle tasks */
115 };