[Cluster-devel] GFS2: Use new workqueue scheme

[Steven Whitehouse]

The recovery workqueue can be unbound and also freezable since
we want it to finish what it is doing if the system is to
be frozen (although why you'd want to freeze a cluster node
is beyond me since it will result in it being ejected from
the cluster). It does still make sense for single node
GFS2 filesystems though.

The glock workqueue will benefit from being able to run more
work items concurrently. A test running postmark shows
improved performance and multi-threaded workloads a likely
to benefit even more.

The delete workqueue is similar to the recovery workqueue in
that it must not get blocked by memory allocations, may
run for a long time, and each individual work should only
be scheduled once anywhere in the system.

Potentially other GFS2 threads might also be converted to
workqueues, but I'll leave that for a later patch.

Signed-off-by: Steven Whitehouse <swhiteho at redhat.com>
Cc: Tejun Heo <tj at kernel.org>

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 8e478e2..fffc1bf 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1783,10 +1783,14 @@ int __init gfs2_glock_init(void)
 	}
 #endif
 
-	glock_workqueue = create_workqueue("glock_workqueue");
+	glock_workqueue = alloc_workqueue("glock_workqueue", WQ_RESCUER |
+					  WQ_HIGHPRI | WQ_CPU_INTENSIVE |
+					  WQ_FREEZEABLE, 0);
 	if (IS_ERR(glock_workqueue))
 		return PTR_ERR(glock_workqueue);
-	gfs2_delete_workqueue = create_workqueue("delete_workqueue");
+	gfs2_delete_workqueue = alloc_workqueue("delete_workqueue", WQ_RESCUER |
+						WQ_UNBOUND | WQ_NON_REENTRANT |
+						WQ_FREEZEABLE, 0);
 	if (IS_ERR(gfs2_delete_workqueue)) {
 		destroy_workqueue(glock_workqueue);
 		return PTR_ERR(gfs2_delete_workqueue);
diff --git a/fs/gfs2/main.c b/fs/gfs2/main.c
index b1e9630..60f3465 100644
--- a/fs/gfs2/main.c
+++ b/fs/gfs2/main.c
@@ -140,7 +140,8 @@ static int __init init_gfs2_fs(void)
 
 	error = -ENOMEM;
 	gfs_recovery_wq = alloc_workqueue("gfs_recovery",
-					  WQ_NON_REENTRANT | WQ_RESCUER, 0);
+					  WQ_NON_REENTRANT | WQ_RESCUER |
+					  WQ_UNBOUND | WQ_FREEZEABLE, 0);
 	if (!gfs_recovery_wq)
 		goto fail_wq;