block, bfq: bring forward seek&think time update (a3f9bce3) · Commits · 戴 / test

Until the base value for request service times gets finally computed for a bfq_queue, the inject limit for that queue does depend on the think-time state (short|long) of the queue. A timely update of the think time then guarantees a quicker activation or deactivation of the injection. Fortunately, the think time of a bfq_queue is updated in the same code path as the inject limit; but after the inject limit. This commits moves the update of the think time before the update of the inject limit. For coherence, it moves the update of the seek time too. Reported-by:

Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu> Tested-by:

Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu> Signed-off-by:

Paolo Valente <paolo.valente@linaro.org> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

block/bfq-iosched.c

+4 −10

Original line number	Diff line number	Diff line
		@@ -4979,19 +4979,9 @@ static void bfq_update_has_short_ttime(struct bfq_data *bfqd,
		static void bfq_rq_enqueued(struct bfq_data bfqd, struct bfq_queue bfqq,
		struct request *rq)
		{
		struct bfq_io_cq *bic = RQ_BIC(rq);

		if (rq->cmd_flags & REQ_META)
		bfqq->meta_pending++;

		bfq_update_io_thinktime(bfqd, bfqq);
		bfq_update_has_short_ttime(bfqd, bfqq, bic);
		bfq_update_io_seektime(bfqd, bfqq, rq);

		bfq_log_bfqq(bfqd, bfqq,
		"rq_enqueued: has_short_ttime=%d (seeky %d)",
		bfq_bfqq_has_short_ttime(bfqq), BFQQ_SEEKY(bfqq));

		bfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq);

		if (bfqq == bfqd->in_service_queue && bfq_bfqq_wait_request(bfqq)) {
		@@ -5079,6 +5069,10 @@ static bool __bfq_insert_request(struct bfq_data bfqd, struct request rq)
		bfqq = new_bfqq;
		}

		bfq_update_io_thinktime(bfqd, bfqq);
		bfq_update_has_short_ttime(bfqd, bfqq, RQ_BIC(rq));
		bfq_update_io_seektime(bfqd, bfqq, rq);

		waiting = bfqq && bfq_bfqq_wait_request(bfqq);
		bfq_add_request(rq);
		idle_timer_disabled = waiting && !bfq_bfqq_wait_request(bfqq);

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