Currently, IO priority set in task's IO context is not reflected in the
bio->bi_ioprio for most IO (only io_uring and direct IO set it). This
results in odd results where process is submitting some bios with one
priority and other bios with a different (unset) priority and due to
differing priorities bios cannot be merged. Make sure bio->bi_ioprio is
always set on bio submission.
Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
block/blk-mq.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index e17d822e6051..7548f8aebea8 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2793,6 +2793,9 @@ static inline struct request *blk_mq_get_cached_request(struct request_queue *q,
static void bio_set_ioprio(struct bio *bio)
{
+ /* Nobody set ioprio so far? Initialize it based on task's nice value */
+ if (IOPRIO_PRIO_CLASS(bio->bi_ioprio) == IOPRIO_CLASS_NONE)
+ bio->bi_ioprio = get_current_ioprio();
blkcg_set_ioprio(bio);
}
--
2.35.3
