linux-kernel - [PATCH 1/5] blk-iolatency: clear use_delay when io.latency is set to zero

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190613223041.606735-2-tj@kernel.org>
Date:   Thu, 13 Jun 2019 15:30:37 -0700
From:   Tejun Heo <tj@...nel.org>
To:     axboe@...nel.dk, jbacik@...com
Cc:     linux-kernel@...r.kernel.org, linux-block@...r.kernel.org,
        kernel-team@...com, dennis@...nel.org, jack@...e.cz,
        Tejun Heo <tj@...nel.org>, stable@...r.kernel.org
Subject: [PATCH 1/5] blk-iolatency: clear use_delay when io.latency is set to zero

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@...nel.org>
Cc: Josef Bacik <jbacik@...com>
Fixes: d70675121546 ("block: introduce blk-iolatency io controller")
Cc: stable@...r.kernel.org # v4.19+
---
 block/blk-iolatency.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index d22e61bced86..17896bb3aaf2 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -778,8 +778,10 @@ 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;
 }
 
-- 
2.17.1