tree 1392526ca5bb0cbe189e7d5ff5d469c51d2ef231
parent 76dc891395dc61e92e2ff31b6161815ce5eb715b
author Damien Le Moal <damien.lemoal@wdc.com> 1542678757 +0900
committer Jens Axboe <axboe@kernel.dk> 1542679429 -0700

block: prevent merging of requests with different priorities

Growing in size a high priority request by merging it with a lower
priority BIO or request will increase the request execution time. This
is the opposite result of the desired effect of high I/O priorities,
namely getting low I/O latencies. Prevent merging of requests and BIOs
that have different I/O priorities to fix this.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>