[SCSI] Revert "[SCSI] qla2xxx: Optimize existing port name server query matching."
[linux/fpc-iii.git] / kernel / sched / stop_task.c
blobda5eb5bed84a2ca8db2443ccb71817d48f06c1f5
1 #include "sched.h"
3 /*
4 * stop-task scheduling class.
6 * The stop task is the highest priority task in the system, it preempts
7 * everything and will be preempted by nothing.
9 * See kernel/stop_machine.c
12 #ifdef CONFIG_SMP
13 static int
14 select_task_rq_stop(struct task_struct *p, int sd_flag, int flags)
16 return task_cpu(p); /* stop tasks as never migrate */
18 #endif /* CONFIG_SMP */
20 static void
21 check_preempt_curr_stop(struct rq *rq, struct task_struct *p, int flags)
23 /* we're never preempted */
26 static struct task_struct *pick_next_task_stop(struct rq *rq)
28 struct task_struct *stop = rq->stop;
30 if (stop && stop->on_rq) {
31 stop->se.exec_start = rq->clock_task;
32 return stop;
35 return NULL;
38 static void
39 enqueue_task_stop(struct rq *rq, struct task_struct *p, int flags)
41 inc_nr_running(rq);
44 static void
45 dequeue_task_stop(struct rq *rq, struct task_struct *p, int flags)
47 dec_nr_running(rq);
50 static void yield_task_stop(struct rq *rq)
52 BUG(); /* the stop task should never yield, its pointless. */
55 static void put_prev_task_stop(struct rq *rq, struct task_struct *prev)
57 struct task_struct *curr = rq->curr;
58 u64 delta_exec;
60 delta_exec = rq->clock_task - curr->se.exec_start;
61 if (unlikely((s64)delta_exec < 0))
62 delta_exec = 0;
64 schedstat_set(curr->se.statistics.exec_max,
65 max(curr->se.statistics.exec_max, delta_exec));
67 curr->se.sum_exec_runtime += delta_exec;
68 account_group_exec_runtime(curr, delta_exec);
70 curr->se.exec_start = rq->clock_task;
71 cpuacct_charge(curr, delta_exec);
74 static void task_tick_stop(struct rq *rq, struct task_struct *curr, int queued)
78 static void set_curr_task_stop(struct rq *rq)
80 struct task_struct *stop = rq->stop;
82 stop->se.exec_start = rq->clock_task;
85 static void switched_to_stop(struct rq *rq, struct task_struct *p)
87 BUG(); /* its impossible to change to this class */
90 static void
91 prio_changed_stop(struct rq *rq, struct task_struct *p, int oldprio)
93 BUG(); /* how!?, what priority? */
96 static unsigned int
97 get_rr_interval_stop(struct rq *rq, struct task_struct *task)
99 return 0;
103 * Simple, special scheduling class for the per-CPU stop tasks:
105 const struct sched_class stop_sched_class = {
106 .next = &rt_sched_class,
108 .enqueue_task = enqueue_task_stop,
109 .dequeue_task = dequeue_task_stop,
110 .yield_task = yield_task_stop,
112 .check_preempt_curr = check_preempt_curr_stop,
114 .pick_next_task = pick_next_task_stop,
115 .put_prev_task = put_prev_task_stop,
117 #ifdef CONFIG_SMP
118 .select_task_rq = select_task_rq_stop,
119 #endif
121 .set_curr_task = set_curr_task_stop,
122 .task_tick = task_tick_stop,
124 .get_rr_interval = get_rr_interval_stop,
126 .prio_changed = prio_changed_stop,
127 .switched_to = switched_to_stop,