SUNRPC: Queue latency-sensitive socket tasks to xprtiod

The response to a write_space notification is very latency sensitive,
so we should queue it to the lower latency xprtiod_workqueue. This
is something we already do for the other cases where an rpc task
holds the transport XPRT_LOCKED bitlock.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

2 files changed, 14 insertions, 1 deletions

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 896691afbb1a..96fdf6011c53 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -461,6 +461,18 @@ static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, struct r
 /*
  * Wake up a task on a specific queue
  */
+void rpc_wake_up_queued_task_on_wq(struct workqueue_struct *wq,
+		struct rpc_wait_queue *queue,
+		struct rpc_task *task)
+{
+	spin_lock_bh(&queue->lock);
+	rpc_wake_up_task_on_wq_queue_locked(wq, queue, task);
+	spin_unlock_bh(&queue->lock);
+}
+
+/*
+ * Wake up a task on a specific queue
+ */
 void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task)
 {
 	spin_lock_bh(&queue->lock);
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 2436fd1125fc..8f0ad4f268da 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -517,7 +517,8 @@ void xprt_write_space(struct rpc_xprt *xprt)
 	if (xprt->snd_task) {
 		dprintk("RPC:       write space: waking waiting task on "
 				"xprt %p\n", xprt);
-		rpc_wake_up_queued_task(&xprt->pending, xprt->snd_task);
+		rpc_wake_up_queued_task_on_wq(xprtiod_workqueue,
+				&xprt->pending, xprt->snd_task);
 	}
 	spin_unlock_bh(&xprt->transport_lock);
 }