When selecting the cpu for a waking RT task, if curr is a non-RT task which is bound only on this cpu, then we can give it a chance to select a different cpu(definitely an idle cpu if existing) for the RT task to avoid curr starving.
Signed-off-by: pang.xunlei <[email protected]> --- kernel/sched/rt.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index da6922e..dc1f7f0 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1340,6 +1340,11 @@ select_task_rq_rt(struct task_struct *p, int cpu, int sd_flag, int flags) * runqueue. Otherwise simply start this RT task * on its current runqueue. * + * If the current task on @p's runqueue is a non-RT task, + * and this task is bound on current runqueue, then try to + * see if we can wake this RT task up on a different runqueue, + * we will definitely find an idle cpu if there is any. + * * 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. @@ -1356,9 +1361,8 @@ select_task_rq_rt(struct task_struct *p, int cpu, int sd_flag, int flags) * This test is optimistic, if we get it wrong the load-balancer * will have to sort it out. */ - if (curr && unlikely(rt_task(curr)) && - (curr->nr_cpus_allowed < 2 || - curr->prio <= p->prio)) { + if (curr && unlikely(curr->nr_cpus_allowed < 2 || + curr->prio <= p->prio)) { int target = find_lowest_rq(p); if (target != -1) -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
