kernel/printk: do not turn off bootconsole in printk_late_init() if keep_bootcon
[linux-2.6.git] / kernel / sched_stoptask.c
1 /*
2  * stop-task scheduling class.
3  *
4  * The stop task is the highest priority task in the system, it preempts
5  * everything and will be preempted by nothing.
6  *
7  * See kernel/stop_machine.c
8  */
9
10 #ifdef CONFIG_SMP
11 static int
12 select_task_rq_stop(struct task_struct *p, int sd_flag, int flags)
13 {
14         return task_cpu(p); /* stop tasks as never migrate */
15 }
16 #endif /* CONFIG_SMP */
17
18 static void
19 check_preempt_curr_stop(struct rq *rq, struct task_struct *p, int flags)
20 {
21         /* we're never preempted */
22 }
23
24 static struct task_struct *pick_next_task_stop(struct rq *rq)
25 {
26         struct task_struct *stop = rq->stop;
27
28         if (stop && stop->on_rq)
29                 return stop;
30
31         return NULL;
32 }
33
34 static void
35 enqueue_task_stop(struct rq *rq, struct task_struct *p, int flags)
36 {
37 }
38
39 static void
40 dequeue_task_stop(struct rq *rq, struct task_struct *p, int flags)
41 {
42 }
43
44 static void yield_task_stop(struct rq *rq)
45 {
46         BUG(); /* the stop task should never yield, its pointless. */
47 }
48
49 static void put_prev_task_stop(struct rq *rq, struct task_struct *prev)
50 {
51 }
52
53 static void task_tick_stop(struct rq *rq, struct task_struct *curr, int queued)
54 {
55 }
56
57 static void set_curr_task_stop(struct rq *rq)
58 {
59 }
60
61 static void switched_to_stop(struct rq *rq, struct task_struct *p)
62 {
63         BUG(); /* its impossible to change to this class */
64 }
65
66 static void
67 prio_changed_stop(struct rq *rq, struct task_struct *p, int oldprio)
68 {
69         BUG(); /* how!?, what priority? */
70 }
71
72 static unsigned int
73 get_rr_interval_stop(struct rq *rq, struct task_struct *task)
74 {
75         return 0;
76 }
77
78 /*
79  * Simple, special scheduling class for the per-CPU stop tasks:
80  */
81 static const struct sched_class stop_sched_class = {
82         .next                   = &rt_sched_class,
83
84         .enqueue_task           = enqueue_task_stop,
85         .dequeue_task           = dequeue_task_stop,
86         .yield_task             = yield_task_stop,
87
88         .check_preempt_curr     = check_preempt_curr_stop,
89
90         .pick_next_task         = pick_next_task_stop,
91         .put_prev_task          = put_prev_task_stop,
92
93 #ifdef CONFIG_SMP
94         .select_task_rq         = select_task_rq_stop,
95 #endif
96
97         .set_curr_task          = set_curr_task_stop,
98         .task_tick              = task_tick_stop,
99
100         .get_rr_interval        = get_rr_interval_stop,
101
102         .prio_changed           = prio_changed_stop,
103         .switched_to            = switched_to_stop,
104 };