Commit c4da7bf5 authored by Zizhi Wo's avatar Zizhi Wo Committed by Jens Axboe
Browse files

blk-throttle: Introduce flag "BIO_TG_BPS_THROTTLED" 



Subsequent patches will split the single queue into separate bps and iops
queues. To prevent IO that has already passed through the bps queue at a
single tg level from being counted toward bps wait time again, we introduce
"BIO_TG_BPS_THROTTLED" flag. Since throttle and QoS operate at different
levels, we reuse the value as "BIO_QOS_THROTTLED".

We set this flag when charge bps and clear it when charge iops, as the bio
will move to the upper-level tg or be dispatched.

This patch does not involve functional changes.

Signed-off-by: default avatarZizhi Wo <wozizhi@huawei.com>
Reviewed-by: default avatarYu Kuai <yukuai3@huawei.com>
Signed-off-by: default avatarZizhi Wo <wozizhi@huaweicloud.com>
Link: https://lore.kernel.org/r/20250506020935.655574-5-wozizhi@huaweicloud.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a404be53

block/blk-throttle.c

+7 −2
Original line number Diff line number Diff line
@@ -792,12 +792,16 @@ static void throtl_charge_bps_bio(struct throtl_grp *tg, struct bio *bio) 
	unsigned int bio_size = throtl_bio_data_size(bio);



	/* Charge the bio to the group */

	if (!bio_flagged(bio, BIO_BPS_THROTTLED))

	if (!bio_flagged(bio, BIO_BPS_THROTTLED) &&

	    !bio_flagged(bio, BIO_TG_BPS_THROTTLED)) {

		bio_set_flag(bio, BIO_TG_BPS_THROTTLED);

		tg->bytes_disp[bio_data_dir(bio)] += bio_size;

	}

}



static void throtl_charge_iops_bio(struct throtl_grp *tg, struct bio *bio)

{

	bio_clear_flag(bio, BIO_TG_BPS_THROTTLED);

	tg->io_disp[bio_data_dir(bio)]++;

}
@@ -823,7 +827,8 @@ static unsigned long tg_dispatch_bps_time(struct throtl_grp *tg, struct bio *bio 


	/* no need to throttle if this bio's bytes have been accounted */

	if (bps_limit == U64_MAX || tg->flags & THROTL_TG_CANCELING ||

	    bio_flagged(bio, BIO_BPS_THROTTLED))

	    bio_flagged(bio, BIO_BPS_THROTTLED) ||

	    bio_flagged(bio, BIO_TG_BPS_THROTTLED))

		return 0;



	tg_update_slice(tg, rw);

include/linux/blk_types.h

+8 −0
Original line number Diff line number Diff line
@@ -296,6 +296,14 @@ enum { 
				 * of this bio. */

	BIO_CGROUP_ACCT,	/* has been accounted to a cgroup */

	BIO_QOS_THROTTLED,	/* bio went through rq_qos throttle path */

	/*

	 * This bio has completed bps throttling at the single tg granularity,

	 * which is different from BIO_BPS_THROTTLED. When the bio is enqueued

	 * into the sq->queued of the upper tg, or is about to be dispatched,

	 * this flag needs to be cleared. Since blk-throttle and rq_qos are not

	 * on the same hierarchical level, reuse the value.

	 */

	BIO_TG_BPS_THROTTLED = BIO_QOS_THROTTLED,

	BIO_QOS_MERGED,		/* but went through rq_qos merge path */

	BIO_REMAPPED,

	BIO_ZONE_WRITE_PLUGGING, /* bio handled through zone write plugging */