SUNRPC: track length of RPC wait queues

RPC wait queue length will eventually be exported to userland via the RPC
iostats interface.

Test plan:
Compile kernel with CONFIG_NFS enabled.

Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index a390c9b8a01e..6c23f73a799a 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -203,6 +203,7 @@ struct rpc_wait_queue {
         unsigned char           priority;               /* current priority */
         unsigned char           count;                  /* # task groups remaining serviced so far */
         unsigned char           nr;                     /* # tasks remaining for cookie */
+        unsigned short          qlen;                   /* total # tasks waiting in queue */
 #ifdef RPC_DEBUG
         const char *            name;
 #endif