Yield task semantic for deadline task is get off from the CPU until our next instance, we mark the task got to sleep until its current deadline by forcing its runtime to zero and update_curr_dl() stops it and the bandwidth timer will wake it up and will give it new scheduling parameters.
Bandwidth timer may fail to start in update_curr_dl() and instead replenishing the budget immediately, however, dl_yielded of dl_se is cleared when bandwidth timer fire, the immediate replenishing miss to reset it. This patch fix it by resetting the dl_yielded flag after the immediate replenishing if fail to start bandwidth timer. Cc: Juri Lelli <[email protected]> Signed-off-by: Wanpeng Li <[email protected]> --- kernel/sched/deadline.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 2d982ce..b102f35 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -633,8 +633,11 @@ static void update_curr_dl(struct rq *rq) __dequeue_task_dl(rq, curr, 0); if (likely(start_dl_timer(dl_se, curr->dl.dl_boosted))) dl_se->dl_throttled = 1; - else + else { enqueue_task_dl(rq, curr, ENQUEUE_REPLENISH); + if (unlikely(dl_se->dl_yielded)) + dl_se->dl_yielded = 0; + } if (!is_leftmost(curr, &rq->dl)) resched_curr(rq); -- 1.9.1 -- 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/
