[3.16.y-ckt stable] Patch "rbd: rbd workqueues need a resque worker" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    rbd: rbd workqueues need a resque worker

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt2.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 88dfb6eb986ca89a50549d85e6f994711df4c73c Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov at redhat.com>
Date: Fri, 10 Oct 2014 18:36:07 +0400
Subject: rbd: rbd workqueues need a resque worker

commit 792c3a914910bd34302c5345578f85cfcb5e2c01 upstream.

Need to use WQ_MEM_RECLAIM for our workqueues to prevent I/O lockups
under memory pressure - we sit on the memory reclaim path.

Signed-off-by: Ilya Dryomov <idryomov at redhat.com>
Tested-by: Micha Krause <micha at krausam.de>
Reviewed-by: Sage Weil <sage at redhat.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/block/rbd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 5c38fe1f4b85..3d2b99a15f62 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -5103,7 +5103,8 @@ static int rbd_dev_device_setup(struct rbd_device *rbd_dev)
 	set_capacity(rbd_dev->disk, rbd_dev->mapping.size / SECTOR_SIZE);
 	set_disk_ro(rbd_dev->disk, rbd_dev->mapping.read_only);

-	rbd_dev->rq_wq = alloc_workqueue("%s", 0, 0, rbd_dev->disk->disk_name);
+	rbd_dev->rq_wq = alloc_workqueue("%s", WQ_MEM_RECLAIM, 0,
+					 rbd_dev->disk->disk_name);
 	if (!rbd_dev->rq_wq) {
 		ret = -ENOMEM;
 		goto err_out_mapping;
--
2.1.0