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Commit | Line | Data |
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029632fb PZ |
1 | #include "sched.h" |
2 | ||
fa72e9e4 IM |
3 | /* |
4 | * idle-task scheduling class. | |
5 | * | |
6 | * (NOTE: these are not related to SCHED_IDLE tasks which are | |
489a71b0 | 7 | * handled in sched/fair.c) |
fa72e9e4 IM |
8 | */ |
9 | ||
e7693a36 | 10 | #ifdef CONFIG_SMP |
0017d735 | 11 | static int |
ac66f547 | 12 | select_task_rq_idle(struct task_struct *p, int cpu, int sd_flag, int flags) |
e7693a36 GH |
13 | { |
14 | return task_cpu(p); /* IDLE tasks as never migrated */ | |
15 | } | |
16 | #endif /* CONFIG_SMP */ | |
38033c37 | 17 | |
fa72e9e4 IM |
18 | /* |
19 | * Idle tasks are unconditionally rescheduled: | |
20 | */ | |
7d478721 | 21 | static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int flags) |
fa72e9e4 IM |
22 | { |
23 | resched_task(rq->idle); | |
24 | } | |
25 | ||
606dba2e PZ |
26 | static struct task_struct * |
27 | pick_next_task_idle(struct rq *rq, struct task_struct *prev) | |
fa72e9e4 | 28 | { |
606dba2e PZ |
29 | if (prev) |
30 | prev->sched_class->put_prev_task(rq, prev); | |
31 | ||
fa72e9e4 | 32 | schedstat_inc(rq, sched_goidle); |
642dbc39 | 33 | #ifdef CONFIG_SMP |
6c3b4d44 | 34 | idle_enter_fair(rq); |
642dbc39 | 35 | #endif |
fa72e9e4 IM |
36 | return rq->idle; |
37 | } | |
38 | ||
39 | /* | |
40 | * It is not legal to sleep in the idle task - print a warning | |
41 | * message if some code attempts to do it: | |
42 | */ | |
43 | static void | |
371fd7e7 | 44 | dequeue_task_idle(struct rq *rq, struct task_struct *p, int flags) |
fa72e9e4 | 45 | { |
05fa785c | 46 | raw_spin_unlock_irq(&rq->lock); |
3df0fc5b | 47 | printk(KERN_ERR "bad: scheduling from the idle thread!\n"); |
fa72e9e4 | 48 | dump_stack(); |
05fa785c | 49 | raw_spin_lock_irq(&rq->lock); |
fa72e9e4 IM |
50 | } |
51 | ||
31ee529c | 52 | static void put_prev_task_idle(struct rq *rq, struct task_struct *prev) |
fa72e9e4 | 53 | { |
38033c37 PZ |
54 | #ifdef CONFIG_SMP |
55 | idle_exit_fair(rq); | |
56 | rq_last_tick_reset(rq); | |
57 | #endif | |
fa72e9e4 IM |
58 | } |
59 | ||
8f4d37ec | 60 | static void task_tick_idle(struct rq *rq, struct task_struct *curr, int queued) |
fa72e9e4 IM |
61 | { |
62 | } | |
63 | ||
83b699ed SV |
64 | static void set_curr_task_idle(struct rq *rq) |
65 | { | |
66 | } | |
67 | ||
da7a735e | 68 | static void switched_to_idle(struct rq *rq, struct task_struct *p) |
cb469845 | 69 | { |
a8941d7e | 70 | BUG(); |
cb469845 SR |
71 | } |
72 | ||
da7a735e PZ |
73 | static void |
74 | prio_changed_idle(struct rq *rq, struct task_struct *p, int oldprio) | |
cb469845 | 75 | { |
a8941d7e | 76 | BUG(); |
cb469845 SR |
77 | } |
78 | ||
6d686f45 | 79 | static unsigned int get_rr_interval_idle(struct rq *rq, struct task_struct *task) |
0d721cea PW |
80 | { |
81 | return 0; | |
82 | } | |
83 | ||
fa72e9e4 IM |
84 | /* |
85 | * Simple, special scheduling class for the per-CPU idle tasks: | |
86 | */ | |
029632fb | 87 | const struct sched_class idle_sched_class = { |
5522d5d5 | 88 | /* .next is NULL */ |
fa72e9e4 IM |
89 | /* no enqueue/yield_task for idle tasks */ |
90 | ||
91 | /* dequeue is not valid, we print a debug message there: */ | |
92 | .dequeue_task = dequeue_task_idle, | |
93 | ||
94 | .check_preempt_curr = check_preempt_curr_idle, | |
95 | ||
96 | .pick_next_task = pick_next_task_idle, | |
97 | .put_prev_task = put_prev_task_idle, | |
98 | ||
681f3e68 | 99 | #ifdef CONFIG_SMP |
4ce72a2c | 100 | .select_task_rq = select_task_rq_idle, |
681f3e68 | 101 | #endif |
fa72e9e4 | 102 | |
83b699ed | 103 | .set_curr_task = set_curr_task_idle, |
fa72e9e4 | 104 | .task_tick = task_tick_idle, |
cb469845 | 105 | |
0d721cea PW |
106 | .get_rr_interval = get_rr_interval_idle, |
107 | ||
cb469845 SR |
108 | .prio_changed = prio_changed_idle, |
109 | .switched_to = switched_to_idle, | |
fa72e9e4 | 110 | }; |