The check in bfq_select_queue() checking whether a waker queue should be selected has a bug and is checking bfqq->next_rq instead of bfqq->waker_bfqq->next_rq to verify whether the waker queue has a request to dispatch. This often results in the condition being false (most notably when the current queue is idling waiting for next request) and thus the waker queue logic is ineffective. Fix the condition. Signed-off-by: Jan Kara <jack@xxxxxxx> --- block/bfq-iosched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 78ba57efd16b..18f85d474c9c 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -4498,7 +4498,7 @@ static struct bfq_queue *bfq_select_queue(struct bfq_data *bfqd) bfqq = bfqq->bic->bfqq[0]; else if (bfq_bfqq_has_waker(bfqq) && bfq_bfqq_busy(bfqq->waker_bfqq) && - bfqq->next_rq && + bfqq->waker_bfqq->next_rq && bfq_serv_to_charge(bfqq->waker_bfqq->next_rq, bfqq->waker_bfqq) <= bfq_bfqq_budget_left(bfqq->waker_bfqq) -- 2.16.4
