[PATCH 3.16.y-ckt 097/254] libceph: ceph-msgr workqueue needs a resque worker

[Luis Henriques]

3.16.7-ckt2 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ilya Dryomov <idryomov at redhat.com>

commit f9865f06f7f18c6661c88d0511f05c48612319cc upstream.

Commit f363e45fd118 ("net/ceph: make ceph_msgr_wq non-reentrant")
effectively removed WQ_MEM_RECLAIM flag from ceph_msgr_wq.  This is
wrong - libceph is very much a memory reclaim path, so restore it.

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>
---
 net/ceph/messenger.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 3d9ddc2842e1..6b15183a68c8 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -291,7 +291,11 @@ int ceph_msgr_init(void)
 	if (ceph_msgr_slab_init())
 		return -ENOMEM;
 
-	ceph_msgr_wq = alloc_workqueue("ceph-msgr", 0, 0);
+	/*
+	 * The number of active work items is limited by the number of
+	 * connections, so leave @max_active at default.
+	 */
+	ceph_msgr_wq = alloc_workqueue("ceph-msgr", WQ_MEM_RECLAIM, 0);
 	if (ceph_msgr_wq)
 		return 0;
 
-- 
2.1.0