Commit a9fc8868 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
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blk-throttle: don't take carryover for prioritized processing of metadata 



Commit 29390bb5 ("blk-throttle: support prioritized processing of metadata")
takes bytes/ios carryover for prioritized processing of metadata. Turns out
we can support it by charging it directly without trimming slice, and the
result is same with carryover.

Cc: Tejun Heo <tj@kernel.org>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20250305043123.3938491-3-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 483a393e

block/blk-throttle.c

+5 −10
Original line number Diff line number Diff line
@@ -1620,13 +1620,6 @@ static bool tg_within_limit(struct throtl_grp *tg, struct bio *bio, bool rw) 
	return tg_may_dispatch(tg, bio, NULL);

}



static void tg_dispatch_in_debt(struct throtl_grp *tg, struct bio *bio, bool rw)

{

	if (!bio_flagged(bio, BIO_BPS_THROTTLED))

		tg->carryover_bytes[rw] -= throtl_bio_data_size(bio);

	tg->carryover_ios[rw]--;

}



bool __blk_throtl_bio(struct bio *bio)

{

	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
@@ -1663,10 +1656,12 @@ bool __blk_throtl_bio(struct bio *bio) 
			/*

			 * IOs which may cause priority inversions are

			 * dispatched directly, even if they're over limit.

			 * Debts are handled by carryover_bytes/ios while

			 * calculating wait time.

			 *

			 * Charge and dispatch directly, and our throttle

			 * control algorithm is adaptive, and extra IO bytes

			 * will be throttled for paying the debt

			 */

			tg_dispatch_in_debt(tg, bio, rw);

			throtl_charge_bio(tg, bio);

		} else {

			/* if above limits, break to queue */

			break;