block, bfq: port commit "cfq-iosched: improve hw_tag detection" (b3c34981) · Commits · 戴 / test

The original commit is commit ("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 <paolo.valente@linaro.org> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

block/bfq-iosched.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -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;

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