Root/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
9static 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 */
17static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int flags)
18{
19    resched_task(rq->idle);
20}
21
22static 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 */
34static void
35dequeue_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
43static void put_prev_task_idle(struct rq *rq, struct task_struct *prev)
44{
45}
46
47#ifdef CONFIG_SMP
48static unsigned long
49load_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
57static int
58move_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
65static void task_tick_idle(struct rq *rq, struct task_struct *curr, int queued)
66{
67}
68
69static void set_curr_task_idle(struct rq *rq)
70{
71}
72
73static 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
83static 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
100unsigned int get_rr_interval_idle(struct task_struct *task)
101{
102    return 0;
103}
104
105/*
106 * Simple, special scheduling class for the per-CPU idle tasks:
107 */
108static const struct sched_class idle_sched_class = {
109    /* .next is NULL */
110    /* no enqueue/yield_task for idle tasks */
111
112    /* dequeue is not valid, we print a debug message there: */
113    .dequeue_task = dequeue_task_idle,
114
115    .check_preempt_curr = check_preempt_curr_idle,
116
117    .pick_next_task = pick_next_task_idle,
118    .put_prev_task = put_prev_task_idle,
119
120#ifdef CONFIG_SMP
121    .select_task_rq = select_task_rq_idle,
122
123    .load_balance = load_balance_idle,
124    .move_one_task = move_one_task_idle,
125#endif
126
127    .set_curr_task = set_curr_task_idle,
128    .task_tick = task_tick_idle,
129
130    .get_rr_interval = get_rr_interval_idle,
131
132    .prio_changed = prio_changed_idle,
133    .switched_to = switched_to_idle,
134
135    /* no .task_new for idle tasks */
136};
137

Archive Download this file

Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master

Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9



interactive