SUNRPC: add a handful of per-xprt counters

Monitor generic transport events.  Add a transport switch callout to
format transport counters for export to user-land.

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>

include/linux/sunrpc/xprt.h

@@ -114,6 +114,7 @@ struct rpc_xprt_ops {
 	void		(*release_request)(struct rpc_task *task);
 	void		(*close)(struct rpc_xprt *xprt);
 	void		(*destroy)(struct rpc_xprt *xprt);
+	void		(*print_stats)(struct rpc_xprt *xprt, struct seq_file *seq);
 };
 
 struct rpc_xprt {
@@ -187,6 +188,18 @@ struct rpc_xprt {
 
 	struct list_head	recv;
 
+	struct {
+		unsigned long		bind_count,	/* total number of binds */
+					connect_count,	/* total number of connects */
+					connect_start,	/* connect start timestamp */
+					connect_time,	/* jiffies waiting for connect */
+					sends,		/* how many complete requests */
+					recvs,		/* how many complete requests */
+					bad_xids;	/* lookup_rqst didn't find XID */
+
+		unsigned long long	req_u,		/* average requests on the wire */
+					bklog_u;	/* backlog queue utilization */
+	} stat;
 
 	void			(*old_data_ready)(struct sock *, int);
 	void			(*old_state_change)(struct sock *);

net/sunrpc/pmap_clnt.c

@@ -82,6 +82,7 @@ rpc_getport(struct rpc_task *task, struct rpc_clnt *clnt)
 	rpc_call_setup(child, &msg, 0);
 
 	/* ... and run the child task */
+	task->tk_xprt->stat.bind_count++;
 	rpc_run_child(task, child, pmap_getport_done);
 	return;
 

net/sunrpc/xprt.c

@@ -548,6 +548,7 @@ void xprt_connect(struct rpc_task *task)
 
 		task->tk_timeout = xprt->connect_timeout;
 		rpc_sleep_on(&xprt->pending, task, xprt_connect_status, NULL);
+		xprt->stat.connect_start = jiffies;
 		xprt->ops->connect(task);
 	}
 	return;
@@ -558,6 +559,8 @@ static void xprt_connect_status(struct rpc_task *task)
 	struct rpc_xprt	*xprt = task->tk_xprt;
 
 	if (task->tk_status >= 0) {
+		xprt->stat.connect_count++;
+		xprt->stat.connect_time += (long)jiffies - xprt->stat.connect_start;
 		dprintk("RPC: %4d xprt_connect_status: connection established\n",
 				task->tk_pid);
 		return;
@@ -601,16 +604,14 @@ static void xprt_connect_status(struct rpc_task *task)
 struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid)
 {
 	struct list_head *pos;
-	struct rpc_rqst	*req = NULL;
 
 	list_for_each(pos, &xprt->recv) {
 		struct rpc_rqst *entry = list_entry(pos, struct rpc_rqst, rq_list);
-		if (entry->rq_xid == xid) {
-			req = entry;
-			break;
-		}
+		if (entry->rq_xid == xid)
+			return entry;
 	}
-	return req;
+	xprt->stat.bad_xids++;
+	return NULL;
 }
 
 /**
@@ -646,6 +647,7 @@ void xprt_complete_rqst(struct rpc_task *task, int copied)
 	dprintk("RPC: %5u xid %08x complete (%d bytes received)\n",
 			task->tk_pid, ntohl(req->rq_xid), copied);
 
+	task->tk_xprt->stat.recvs++;
 	list_del_init(&req->rq_list);
 	req->rq_received = req->rq_private_buf.len = copied;
 	rpc_wake_up_task(task);
@@ -744,12 +746,19 @@ void xprt_transmit(struct rpc_task *task)
 	if (status == 0) {
 		dprintk("RPC: %4d xmit complete\n", task->tk_pid);
 		spin_lock_bh(&xprt->transport_lock);
+
 		xprt->ops->set_retrans_timeout(task);
+
+		xprt->stat.sends++;
+		xprt->stat.req_u += xprt->stat.sends - xprt->stat.recvs;
+		xprt->stat.bklog_u += xprt->backlog.qlen;
+
 		/* Don't race with disconnect */
 		if (!xprt_connected(xprt))
 			task->tk_status = -ENOTCONN;
 		else if (!req->rq_received)
 			rpc_sleep_on(&xprt->pending, task, NULL, xprt_timer);
+
 		xprt->ops->release_xprt(xprt, task);
 		spin_unlock_bh(&xprt->transport_lock);
 		return;

net/sunrpc/xprtsock.c

@@ -1114,6 +1114,8 @@ static void xs_tcp_connect_worker(void *args)
 	}
 
 	/* Tell the socket layer to start connecting... */
+	xprt->stat.connect_count++;
+	xprt->stat.connect_start = jiffies;
 	status = sock->ops->connect(sock, (struct sockaddr *) &xprt->addr,
 			sizeof(xprt->addr), O_NONBLOCK);
 	dprintk("RPC: %p  connect status %d connected %d sock state %d\n",
@@ -1177,6 +1179,50 @@ static void xs_connect(struct rpc_task *task)
 	}
 }
 
+/**
+ * xs_udp_print_stats - display UDP socket-specifc stats
+ * @xprt: rpc_xprt struct containing statistics
+ * @seq: output file
+ *
+ */
+static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
+{
+	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %Lu %Lu\n",
+			xprt->port,
+			xprt->stat.bind_count,
+			xprt->stat.sends,
+			xprt->stat.recvs,
+			xprt->stat.bad_xids,
+			xprt->stat.req_u,
+			xprt->stat.bklog_u);
+}
+
+/**
+ * xs_tcp_print_stats - display TCP socket-specifc stats
+ * @xprt: rpc_xprt struct containing statistics
+ * @seq: output file
+ *
+ */
+static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
+{
+	long idle_time = 0;
+
+	if (xprt_connected(xprt))
+		idle_time = (long)(jiffies - xprt->last_used) / HZ;
+
+	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu %Lu %Lu\n",
+			xprt->port,
+			xprt->stat.bind_count,
+			xprt->stat.connect_count,
+			xprt->stat.connect_time,
+			idle_time,
+			xprt->stat.sends,
+			xprt->stat.recvs,
+			xprt->stat.bad_xids,
+			xprt->stat.req_u,
+			xprt->stat.bklog_u);
+}
+
 static struct rpc_xprt_ops xs_udp_ops = {
 	.set_buffer_size	= xs_udp_set_buffer_size,
 	.reserve_xprt		= xprt_reserve_xprt_cong,
@@ -1191,6 +1237,7 @@ static struct rpc_xprt_ops xs_udp_ops = {
 	.release_request	= xprt_release_rqst_cong,
 	.close			= xs_close,
 	.destroy		= xs_destroy,
+	.print_stats		= xs_udp_print_stats,
 };
 
 static struct rpc_xprt_ops xs_tcp_ops = {
@@ -1204,6 +1251,7 @@ static struct rpc_xprt_ops xs_tcp_ops = {
 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
 	.close			= xs_close,
 	.destroy		= xs_destroy,
+	.print_stats		= xs_tcp_print_stats,
 };
 
 /**