diff options
| -rw-r--r-- | kernel/sched_rt.c | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index d10c80ebb67a..6a02b38ab653 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -960,18 +960,18 @@ select_task_rq_rt(struct rq *rq, struct task_struct *p, int sd_flag, int flags) * runqueue. Otherwise simply start this RT task * on its current runqueue. * - * We want to avoid overloading runqueues. Even if - * the RT task is of higher priority than the current RT task. - * RT tasks behave differently than other tasks. If - * one gets preempted, we try to push it off to another queue. - * So trying to keep a preempting RT task on the same - * cache hot CPU will force the running RT task to - * a cold CPU. So we waste all the cache for the lower - * RT task in hopes of saving some of a RT task - * that is just being woken and probably will have - * cold cache anyway. + * We want to avoid overloading runqueues. If the woken + * task is a higher priority, then it will stay on this CPU + * and the lower prio task should be moved to another CPU. + * Even though this will probably make the lower prio task + * lose its cache, we do not want to bounce a higher task + * around just because it gave up its CPU, perhaps for a + * lock? + * + * For equal prio tasks, we just let the scheduler sort it out. */ if (unlikely(rt_task(rq->curr)) && + rq->curr->prio < p->prio && (p->rt.nr_cpus_allowed > 1)) { int cpu = find_lowest_rq(p); @@ -1491,6 +1491,8 @@ static void task_woken_rt(struct rq *rq, struct task_struct *p) if (!task_running(rq, p) && !test_tsk_need_resched(rq->curr) && has_pushable_tasks(rq) && + rt_task(rq->curr) && + rq->curr->prio < p->prio && p->rt.nr_cpus_allowed > 1) push_rt_tasks(rq); } |