From b3c3498112ffafa5f613bb482f9723996bfd5e4f Mon Sep 17 00:00:00 2001 From: Paolo Valente Date: Tue, 29 Jan 2019 12:06:36 +0100 Subject: block, bfq: port commit "cfq-iosched: improve hw_tag detection" The original commit is commit 1a1238a7dd48 ("cfq-iosched: improve hw_tag detection") and has the following commit message: If active queue hasn't enough requests and idle window opens, cfq will not dispatch sufficient requests to hardware. In such situation, current code will zero hw_tag. But this is because cfq doesn't dispatch enough requests instead of hardware queue doesn't work. Don't zero hw_tag in such case. Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe --- block/bfq-iosched.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'block') diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 48b579032d14..2ab53d93ba12 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -4786,6 +4786,8 @@ static void bfq_insert_requests(struct blk_mq_hw_ctx *hctx, static void bfq_update_hw_tag(struct bfq_data *bfqd) { + struct bfq_queue *bfqq = bfqd->in_service_queue; + bfqd->max_rq_in_driver = max_t(int, bfqd->max_rq_in_driver, bfqd->rq_in_driver); @@ -4801,6 +4803,17 @@ static void bfq_update_hw_tag(struct bfq_data *bfqd) if (bfqd->rq_in_driver + bfqd->queued <= BFQ_HW_QUEUE_THRESHOLD) return; + /* + * If active queue hasn't enough requests and can idle, bfq might not + * dispatch sufficient requests to hardware. Don't zero hw_tag in this + * case + */ + if (bfqq && bfq_bfqq_has_short_ttime(bfqq) && + bfqq->dispatched + bfqq->queued[0] + bfqq->queued[1] < + BFQ_HW_QUEUE_THRESHOLD && + bfqd->rq_in_driver < BFQ_HW_QUEUE_THRESHOLD) + return; + if (bfqd->hw_tag_samples++ < BFQ_HW_QUEUE_SAMPLES) return; -- cgit v1.2.3