diff options
| author | Jens Axboe <axboe@kernel.dk> | 2021-11-13 13:37:38 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-11-29 06:38:35 -0700 |
| commit | 25c4b5e058578066db56d757ad3a7adeaff35856 (patch) | |
| tree | 53dc562b436557bc193792539586bcfb1309f723 /block/blk-ioprio.c | |
| parent | 1e9c23034d7b216b02f1491505779dfe9a1a6e23 (diff) | |
blk-ioprio: don't set bio priority if not needed
We don't need to write to the bio if:
1) No ioprio value has ever been assigned to the blkcg
2) We wouldn't anyway, depending on bio and blkcg IO priority
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-ioprio.c')
| -rw-r--r-- | block/blk-ioprio.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/block/blk-ioprio.c b/block/blk-ioprio.c index 332a07761bf8..2e7f10e1c03f 100644 --- a/block/blk-ioprio.c +++ b/block/blk-ioprio.c @@ -62,6 +62,7 @@ struct ioprio_blkg { struct ioprio_blkcg { struct blkcg_policy_data cpd; enum prio_policy prio_policy; + bool prio_set; }; static inline struct ioprio_blkg *pd_to_ioprio(struct blkg_policy_data *pd) @@ -112,7 +113,7 @@ static ssize_t ioprio_set_prio_policy(struct kernfs_open_file *of, char *buf, if (ret < 0) return ret; blkcg->prio_policy = ret; - + blkcg->prio_set = true; return nbytes; } @@ -190,6 +191,10 @@ static void blkcg_ioprio_track(struct rq_qos *rqos, struct request *rq, struct bio *bio) { struct ioprio_blkcg *blkcg = ioprio_blkcg_from_bio(bio); + u16 prio; + + if (!blkcg->prio_set) + return; /* * Except for IOPRIO_CLASS_NONE, higher I/O priority numbers @@ -199,8 +204,10 @@ static void blkcg_ioprio_track(struct rq_qos *rqos, struct request *rq, * bio I/O priority is not modified. If the bio I/O priority equals * IOPRIO_CLASS_NONE, the cgroup I/O priority is assigned to the bio. */ - bio->bi_ioprio = max_t(u16, bio->bi_ioprio, - IOPRIO_PRIO_VALUE(blkcg->prio_policy, 0)); + prio = max_t(u16, bio->bi_ioprio, + IOPRIO_PRIO_VALUE(blkcg->prio_policy, 0)); + if (prio > bio->bi_ioprio) + bio->bi_ioprio = prio; } static void blkcg_ioprio_exit(struct rq_qos *rqos) |