diff options
| author | Harshad Shirwadkar <harshadshirwadkar@gmail.com> | 2019-10-05 21:59:27 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-10-06 18:26:41 +0300 |
| commit | b84477d3ebb96294f87dc3161e53fa8fe22d9bfd (patch) | |
| tree | c69d5489e1f70ed4b22a7753ac61c26660b8454a /block/blk-rq-qos.h | |
| parent | 0e48f51cbbfbdb79149806de14dcb8bf0f01ca94 (diff) | |
| download | linux-b84477d3ebb96294f87dc3161e53fa8fe22d9bfd.tar.xz | |
blk-wbt: fix performance regression in wbt scale_up/scale_down
scale_up wakes up waiters after scaling up. But after scaling max, it
should not wake up more waiters as waiters will not have anything to
do. This patch fixes this by making scale_up (and also scale_down)
return when threshold is reached.
This bug causes increased fdatasync latency when fdatasync and dd
conv=sync are performed in parallel on 4.19 compared to 4.14. This
bug was introduced during refactoring of blk-wbt code.
Fixes: a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt")
Cc: stable@vger.kernel.org
Cc: Josef Bacik <jbacik@fb.com>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-rq-qos.h')
| -rw-r--r-- | block/blk-rq-qos.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h index 08a09dbe0f4b..e8cb68f6958a 100644 --- a/block/blk-rq-qos.h +++ b/block/blk-rq-qos.h @@ -130,8 +130,8 @@ void rq_qos_wait(struct rq_wait *rqw, void *private_data, acquire_inflight_cb_t *acquire_inflight_cb, cleanup_cb_t *cleanup_cb); bool rq_wait_inc_below(struct rq_wait *rq_wait, unsigned int limit); -void rq_depth_scale_up(struct rq_depth *rqd); -void rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle); +bool rq_depth_scale_up(struct rq_depth *rqd); +bool rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle); bool rq_depth_calc_max_depth(struct rq_depth *rqd); void __rq_qos_cleanup(struct rq_qos *rqos, struct bio *bio); |