Commit 73efdc5d authored Jun 13, 2019 by Tejun Heo Committed by Greg Kroah-Hartman Jul 26, 2019

blk-iolatency: clear use_delay when io.latency is set to zero



commit 5de0073fcd50cc1f150895a7bb04d3cf8067b1d7 upstream.

If use_delay was non-zero when the latency target of a cgroup was set
to zero, it will stay stuck until io.latency is enabled on the cgroup
again.  This keeps readahead disabled for the cgroup impacting
performance negatively.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Josef Bacik <jbacik@fb.com>
Fixes: d7067512 ("block: introduce blk-iolatency io controller")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 1ab644bd

block/blk-iolatency.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -746,8 +746,10 @@ static int iolatency_set_min_lat_nsec(struct blkcg_gq *blkg, u64 val)

		if (!oldval && val)
		return 1;
		if (oldval && !val)
		if (oldval && !val) {
		blkcg_clear_delay(blkg);
		return -1;
		}
		return 0;
		}