rxrpc: Add stats procfile and DATA packet stats

Add a procfile, /proc/net/rxrpc/stats, to display some statistics about
what rxrpc has been doing.  Writing a blank line to the stats file will
clear the increment-only counters.  Allocated resource counters don't get
cleared.

Add some counters to count various things about DATA packets, including the
number created, transmitted and retransmitted and the number received, the
number of ACK-requests markings and the number of jumbo packets received.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

net/rxrpc/ar-internal.h

@@ -93,6 +93,14 @@ struct rxrpc_net {
 	struct list_head	peer_keepalive_new;
 	struct timer_list	peer_keepalive_timer;
 	struct work_struct	peer_keepalive_work;
+
+	atomic_t		stat_tx_data;
+	atomic_t		stat_tx_data_retrans;
+	atomic_t		stat_tx_data_send;
+	atomic_t		stat_tx_data_send_frag;
+	atomic_t		stat_rx_data;
+	atomic_t		stat_rx_data_reqack;
+	atomic_t		stat_rx_data_jumbo;
 };
 
 /*
@@ -1092,6 +1100,15 @@ void rxrpc_get_skb(struct sk_buff *, enum rxrpc_skb_trace);
 void rxrpc_free_skb(struct sk_buff *, enum rxrpc_skb_trace);
 void rxrpc_purge_queue(struct sk_buff_head *);
 
+/*
+ * stats.c
+ */
+int rxrpc_stats_show(struct seq_file *seq, void *v);
+int rxrpc_stats_clear(struct file *file, char *buf, size_t size);
+
+#define rxrpc_inc_stat(rxnet, s) atomic_inc(&(rxnet)->s)
+#define rxrpc_dec_stat(rxnet, s) atomic_dec(&(rxnet)->s)
+
 /*
  * sysctl.c
  */

net/rxrpc/call_event.c

@@ -261,6 +261,7 @@ static void rxrpc_resend(struct rxrpc_call *call, unsigned long now_j)
 		rxrpc_get_skb(skb, rxrpc_skb_got);
 		spin_unlock_bh(&call->lock);
 
+		rxrpc_inc_stat(call->rxnet, stat_tx_data_retrans);
 		if (rxrpc_send_data_packet(call, skb, true) < 0) {
 			rxrpc_free_skb(skb, rxrpc_skb_freed);
 			return;

net/rxrpc/input.c

@@ -443,6 +443,12 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
 		}
 	}
 
+	rxrpc_inc_stat(call->rxnet, stat_rx_data);
+	if (sp->hdr.flags & RXRPC_REQUEST_ACK)
+		rxrpc_inc_stat(call->rxnet, stat_rx_data_reqack);
+	if (sp->hdr.flags & RXRPC_JUMBO_PACKET)
+		rxrpc_inc_stat(call->rxnet, stat_rx_data_jumbo);
+
 	spin_lock(&call->input_lock);
 
 	/* Received data implicitly ACKs all of the request packets we sent

net/rxrpc/net_ns.c

@@ -101,6 +101,8 @@ static __net_init int rxrpc_init_net(struct net *net)
 	proc_create_net("locals", 0444, rxnet->proc_net,
 			&rxrpc_local_seq_ops,
 			sizeof(struct seq_net_private));
+	proc_create_net_single_write("stats", S_IFREG | 0644, rxnet->proc_net,
+				     rxrpc_stats_show, rxrpc_stats_clear, NULL);
 	return 0;
 
 err_proc:

net/rxrpc/output.c

@@ -462,6 +462,7 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
 	 *   - in which case, we'll have processed the ICMP error
 	 *     message and update the peer record
 	 */
+	rxrpc_inc_stat(call->rxnet, stat_tx_data_send);
 	ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
 	conn->params.peer->last_tx_at = ktime_get_seconds();
 
@@ -537,6 +538,7 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
 	case AF_INET:
 		ip_sock_set_mtu_discover(conn->params.local->socket->sk,
 				IP_PMTUDISC_DONT);
+		rxrpc_inc_stat(call->rxnet, stat_tx_data_send_frag);
 		ret = kernel_sendmsg(conn->params.local->socket, &msg,
 				     iov, 2, len);
 		conn->params.peer->last_tx_at = ktime_get_seconds();

net/rxrpc/proc.c

@@ -397,3 +397,51 @@ const struct seq_operations rxrpc_local_seq_ops = {
 	.stop   = rxrpc_local_seq_stop,
 	.show   = rxrpc_local_seq_show,
 };
+
+/*
+ * Display stats in /proc/net/rxrpc/stats
+ */
+int rxrpc_stats_show(struct seq_file *seq, void *v)
+{
+	struct rxrpc_net *rxnet = rxrpc_net(seq_file_single_net(seq));
+
+	seq_printf(seq,
+		   "Data     : send=%u sendf=%u\n",
+		   atomic_read(&rxnet->stat_tx_data_send),
+		   atomic_read(&rxnet->stat_tx_data_send_frag));
+	seq_printf(seq,
+		   "Data-Tx  : nr=%u retrans=%u\n",
+		   atomic_read(&rxnet->stat_tx_data),
+		   atomic_read(&rxnet->stat_tx_data_retrans));
+	seq_printf(seq,
+		   "Data-Rx  : nr=%u reqack=%u jumbo=%u\n",
+		   atomic_read(&rxnet->stat_rx_data),
+		   atomic_read(&rxnet->stat_rx_data_reqack),
+		   atomic_read(&rxnet->stat_rx_data_jumbo));
+	seq_printf(seq,
+		   "Buffers  : txb=%u rxb=%u\n",
+		   atomic_read(&rxrpc_n_tx_skbs),
+		   atomic_read(&rxrpc_n_rx_skbs));
+	return 0;
+}
+
+/*
+ * Clear stats if /proc/net/rxrpc/stats is written to.
+ */
+int rxrpc_stats_clear(struct file *file, char *buf, size_t size)
+{
+	struct seq_file *m = file->private_data;
+	struct rxrpc_net *rxnet = rxrpc_net(seq_file_single_net(m));
+
+	if (size > 1 || (size == 1 && buf[0] != '\n'))
+		return -EINVAL;
+
+	atomic_set(&rxnet->stat_tx_data, 0);
+	atomic_set(&rxnet->stat_tx_data_retrans, 0);
+	atomic_set(&rxnet->stat_tx_data_send, 0);
+	atomic_set(&rxnet->stat_tx_data_send_frag, 0);
+	atomic_set(&rxnet->stat_rx_data, 0);
+	atomic_set(&rxnet->stat_rx_data_reqack, 0);
+	atomic_set(&rxnet->stat_rx_data_jumbo, 0);
+	return size;
+}

net/rxrpc/sendmsg.c

@@ -200,6 +200,8 @@ static int rxrpc_queue_packet(struct rxrpc_sock *rx, struct rxrpc_call *call,
 
 	_net("queue skb %p [%d]", skb, seq);
 
+	rxrpc_inc_stat(call->rxnet, stat_tx_data);
+
 	ASSERTCMP(seq, ==, call->tx_top + 1);
 
 	if (last)