diff options
Diffstat (limited to 'kernel/sched_idletask.c')
-rw-r--r-- | kernel/sched_idletask.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/kernel/sched_idletask.c b/kernel/sched_idletask.c new file mode 100644 index 0000000..8a21a2e --- /dev/null +++ b/kernel/sched_idletask.c @@ -0,0 +1,128 @@ +/* + * idle-task scheduling class. + * + * (NOTE: these are not related to SCHED_IDLE tasks which are + * handled in sched_fair.c) + */ + +#ifdef CONFIG_SMP +static int select_task_rq_idle(struct task_struct *p, int sync) +{ + return task_cpu(p); /* IDLE tasks as never migrated */ +} +#endif /* CONFIG_SMP */ +/* + * Idle tasks are unconditionally rescheduled: + */ +static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int sync) +{ + resched_task(rq->idle); +} + +static struct task_struct *pick_next_task_idle(struct rq *rq) +{ + schedstat_inc(rq, sched_goidle); + + return rq->idle; +} + +/* + * It is not legal to sleep in the idle task - print a warning + * message if some code attempts to do it: + */ +static void +dequeue_task_idle(struct rq *rq, struct task_struct *p, int sleep) +{ + spin_unlock_irq(&rq->lock); + printk(KERN_ERR "bad: scheduling from the idle thread!\n"); + dump_stack(); + spin_lock_irq(&rq->lock); +} + +static void put_prev_task_idle(struct rq *rq, struct task_struct *prev) +{ +} + +#ifdef CONFIG_SMP +static unsigned long +load_balance_idle(struct rq *this_rq, int this_cpu, struct rq *busiest, + unsigned long max_load_move, + struct sched_domain *sd, enum cpu_idle_type idle, + int *all_pinned, int *this_best_prio) +{ + return 0; +} + +static int +move_one_task_idle(struct rq *this_rq, int this_cpu, struct rq *busiest, + struct sched_domain *sd, enum cpu_idle_type idle) +{ + return 0; +} +#endif + +static void task_tick_idle(struct rq *rq, struct task_struct *curr, int queued) +{ +} + +static void set_curr_task_idle(struct rq *rq) +{ +} + +static void switched_to_idle(struct rq *rq, struct task_struct *p, + int running) +{ + /* Can this actually happen?? */ + if (running) + resched_task(rq->curr); + else + check_preempt_curr(rq, p, 0); +} + +static void prio_changed_idle(struct rq *rq, struct task_struct *p, + int oldprio, int running) +{ + /* This can happen for hot plug CPUS */ + + /* + * Reschedule if we are currently running on this runqueue and + * our priority decreased, or if we are not currently running on + * this runqueue and our priority is higher than the current's + */ + if (running) { + if (p->prio > oldprio) + resched_task(rq->curr); + } else + check_preempt_curr(rq, p, 0); +} + +/* + * Simple, special scheduling class for the per-CPU idle tasks: + */ +static const struct sched_class idle_sched_class = { + /* .next is NULL */ + /* no enqueue/yield_task for idle tasks */ + + /* dequeue is not valid, we print a debug message there: */ + .dequeue_task = dequeue_task_idle, + + .check_preempt_curr = check_preempt_curr_idle, + + .pick_next_task = pick_next_task_idle, + .put_prev_task = put_prev_task_idle, + +#ifdef CONFIG_SMP + .select_task_rq = select_task_rq_idle, + + .load_balance = load_balance_idle, + .move_one_task = move_one_task_idle, +#endif + + .set_curr_task = set_curr_task_idle, + .task_tick = task_tick_idle, + + .prio_changed = prio_changed_idle, + .switched_to = switched_to_idle, + + /* no .task_new for idle tasks */ +}; |