[PATCH 5.15 068/230] block: only mark bio as tracked if it really is tracked

Greg Kroah-Hartman
2022-07-11T09:46:32Z

From: Jens Axboe <axboe@kernel.dk>

[ Upstream commit 90b8faa0e8de1b02b619fb33f6c6e1e13e7d1d70 ]

We set BIO_TRACKED unconditionally when rq_qos_throttle() is called, even
though we may not even have an rq_qos handler. Only mark it as TRACKED if
it really is potentially tracked.

This saves considerable time for the case where the bio isn't tracked:

2.64% -1.65% [kernel.vmlinux] [k] bio_endio

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
block/blk-rq-qos.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h
index f000f83e0621..3cfbc8668cba 100644
--- a/block/blk-rq-qos.h
+++ b/block/blk-rq-qos.h
@@ -189,9 +189,10 @@ static inline void rq_qos_throttle(struct request_queue *q, struct bio *bio)
* BIO_TRACKED lets controllers know that a bio went through the
* normal rq_qos path.
*/
- bio_set_flag(bio, BIO_TRACKED);
- if (q->rq_qos)
+ if (q->rq_qos) {
+ bio_set_flag(bio, BIO_TRACKED);
__rq_qos_throttle(q->rq_qos, bio);
+ }
}

static inline void rq_qos_track(struct request_queue *q, struct request *rq,
--
2.35.1