From: Luca Abeni <luca.ab...@santannapisa.it> When switching to -deadline, if the scheduling deadline of a task is in the past then switched_to_dl() calls setup_new_entity() to properly initialize the scheduling deadline and runtime.
The problem is that the task is enqueued _before_ having its parameters initialized by setup_new_entity(), and this can cause problems. For example, a task with its out-of-date deadline in the past will potentially be enqueued as the highest priority one; however, its adjusted deadline may not be the earliest one. This patch fixes the problem by initializing the task's parameters before enqueuing it. Signed-off-by: Luca Abeni <luca.ab...@santannapisa.it> Reviewed-by: Daniel Bristot de Oliveira <bris...@redhat.com> --- kernel/sched/deadline.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index a2ce590..ec53d24 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -950,6 +950,10 @@ enqueue_dl_entity(struct sched_dl_entity *dl_se, update_dl_entity(dl_se, pi_se); else if (flags & ENQUEUE_REPLENISH) replenish_dl_entity(dl_se, pi_se); + else if ((flags & ENQUEUE_RESTORE) && + dl_time_before(dl_se->deadline, + rq_clock(rq_of_dl_rq(dl_rq_of_se(dl_se))))) + setup_new_dl_entity(dl_se); __enqueue_dl_entity(dl_se); } @@ -1767,14 +1771,6 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p) if (!task_on_rq_queued(p)) return; - /* - * If p is boosted we already updated its params in - * rt_mutex_setprio()->enqueue_task(..., ENQUEUE_REPLENISH), - * p's deadline being now already after rq_clock(rq). - */ - if (dl_time_before(p->dl.deadline, rq_clock(rq))) - setup_new_dl_entity(&p->dl); - if (rq->curr != p) { #ifdef CONFIG_SMP if (p->nr_cpus_allowed > 1 && rq->dl.overloaded) -- 2.7.4