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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 | 22 | { |
8875125e | 23 | resched_curr(rq); |
fa72e9e4 IM |
24 | } |
25 | ||
606dba2e | 26 | static struct task_struct * |
d8ac8971 | 27 | pick_next_task_idle(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) |
fa72e9e4 | 28 | { |
3f1d2a31 | 29 | put_prev_task(rq, prev); |
10e2f1ac | 30 | update_idle_core(rq); |
ae92882e | 31 | schedstat_inc(rq->sched_goidle); |
fa72e9e4 IM |
32 | return rq->idle; |
33 | } | |
34 | ||
35 | /* | |
36 | * It is not legal to sleep in the idle task - print a warning | |
37 | * message if some code attempts to do it: | |
38 | */ | |
39 | static void | |
371fd7e7 | 40 | dequeue_task_idle(struct rq *rq, struct task_struct *p, int flags) |
fa72e9e4 | 41 | { |
05fa785c | 42 | raw_spin_unlock_irq(&rq->lock); |
3df0fc5b | 43 | printk(KERN_ERR "bad: scheduling from the idle thread!\n"); |
fa72e9e4 | 44 | dump_stack(); |
05fa785c | 45 | raw_spin_lock_irq(&rq->lock); |
fa72e9e4 IM |
46 | } |
47 | ||
31ee529c | 48 | static void put_prev_task_idle(struct rq *rq, struct task_struct *prev) |
fa72e9e4 | 49 | { |
38033c37 | 50 | rq_last_tick_reset(rq); |
fa72e9e4 IM |
51 | } |
52 | ||
8f4d37ec | 53 | static void task_tick_idle(struct rq *rq, struct task_struct *curr, int queued) |
fa72e9e4 IM |
54 | { |
55 | } | |
56 | ||
83b699ed SV |
57 | static void set_curr_task_idle(struct rq *rq) |
58 | { | |
59 | } | |
60 | ||
da7a735e | 61 | static void switched_to_idle(struct rq *rq, struct task_struct *p) |
cb469845 | 62 | { |
a8941d7e | 63 | BUG(); |
cb469845 SR |
64 | } |
65 | ||
da7a735e PZ |
66 | static void |
67 | prio_changed_idle(struct rq *rq, struct task_struct *p, int oldprio) | |
cb469845 | 68 | { |
a8941d7e | 69 | BUG(); |
cb469845 SR |
70 | } |
71 | ||
6d686f45 | 72 | static unsigned int get_rr_interval_idle(struct rq *rq, struct task_struct *task) |
0d721cea PW |
73 | { |
74 | return 0; | |
75 | } | |
76 | ||
90e362f4 TG |
77 | static void update_curr_idle(struct rq *rq) |
78 | { | |
79 | } | |
80 | ||
fa72e9e4 IM |
81 | /* |
82 | * Simple, special scheduling class for the per-CPU idle tasks: | |
83 | */ | |
029632fb | 84 | const struct sched_class idle_sched_class = { |
5522d5d5 | 85 | /* .next is NULL */ |
fa72e9e4 IM |
86 | /* no enqueue/yield_task for idle tasks */ |
87 | ||
88 | /* dequeue is not valid, we print a debug message there: */ | |
89 | .dequeue_task = dequeue_task_idle, | |
90 | ||
91 | .check_preempt_curr = check_preempt_curr_idle, | |
92 | ||
93 | .pick_next_task = pick_next_task_idle, | |
94 | .put_prev_task = put_prev_task_idle, | |
95 | ||
681f3e68 | 96 | #ifdef CONFIG_SMP |
4ce72a2c | 97 | .select_task_rq = select_task_rq_idle, |
c5b28038 | 98 | .set_cpus_allowed = set_cpus_allowed_common, |
681f3e68 | 99 | #endif |
fa72e9e4 | 100 | |
83b699ed | 101 | .set_curr_task = set_curr_task_idle, |
fa72e9e4 | 102 | .task_tick = task_tick_idle, |
cb469845 | 103 | |
0d721cea PW |
104 | .get_rr_interval = get_rr_interval_idle, |
105 | ||
cb469845 SR |
106 | .prio_changed = prio_changed_idle, |
107 | .switched_to = switched_to_idle, | |
90e362f4 | 108 | .update_curr = update_curr_idle, |
fa72e9e4 | 109 | }; |