diff options
Diffstat (limited to 'kernel/sched_rt.c')
| -rw-r--r-- | kernel/sched_rt.c | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index a5a45104603a..57fa3d96847b 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -779,7 +779,92 @@ static void leave_domain_rt(struct rq *rq) if (rq->rt.overloaded) rt_clear_overload(rq); } + +/* + * When switch from the rt queue, we bring ourselves to a position + * that we might want to pull RT tasks from other runqueues. + */ +static void switched_from_rt(struct rq *rq, struct task_struct *p, + int running) +{ + /* + * If there are other RT tasks then we will reschedule + * and the scheduling of the other RT tasks will handle + * the balancing. But if we are the last RT task + * we may need to handle the pulling of RT tasks + * now. + */ + if (!rq->rt.rt_nr_running) + pull_rt_task(rq); +} +#endif /* CONFIG_SMP */ + +/* + * When switching a task to RT, we may overload the runqueue + * with RT tasks. In this case we try to push them off to + * other runqueues. + */ +static void switched_to_rt(struct rq *rq, struct task_struct *p, + int running) +{ + int check_resched = 1; + + /* + * If we are already running, then there's nothing + * that needs to be done. But if we are not running + * we may need to preempt the current running task. + * If that current running task is also an RT task + * then see if we can move to another run queue. + */ + if (!running) { +#ifdef CONFIG_SMP + if (rq->rt.overloaded && push_rt_task(rq) && + /* Don't resched if we changed runqueues */ + rq != task_rq(p)) + check_resched = 0; +#endif /* CONFIG_SMP */ + if (check_resched && p->prio < rq->curr->prio) + resched_task(rq->curr); + } +} + +/* + * Priority of the task has changed. This may cause + * us to initiate a push or pull. + */ +static void prio_changed_rt(struct rq *rq, struct task_struct *p, + int oldprio, int running) +{ + if (running) { +#ifdef CONFIG_SMP + /* + * If our priority decreases while running, we + * may need to pull tasks to this runqueue. + */ + if (oldprio < p->prio) + pull_rt_task(rq); + /* + * If there's a higher priority task waiting to run + * then reschedule. + */ + if (p->prio > rq->rt.highest_prio) + resched_task(p); +#else + /* For UP simply resched on drop of prio */ + if (oldprio < p->prio) + resched_task(p); #endif /* CONFIG_SMP */ + } else { + /* + * This task is not running, but if it is + * greater than the current running task + * then reschedule. + */ + if (p->prio < rq->curr->prio) + resched_task(rq->curr); + } +} + static void task_tick_rt(struct rq *rq, struct task_struct *p) { @@ -837,8 +922,12 @@ const struct sched_class rt_sched_class = { .pre_schedule = pre_schedule_rt, .post_schedule = post_schedule_rt, .task_wake_up = task_wake_up_rt, + .switched_from = switched_from_rt, #endif .set_curr_task = set_curr_task_rt, .task_tick = task_tick_rt, + + .prio_changed = prio_changed_rt, + .switched_to = switched_to_rt, }; |