rxrpc: Record stats for why the REQUEST-ACK flag is being set

Record stats for why the REQUEST-ACK flag is being set.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

include/trace/events/rxrpc.h

@@ -250,6 +250,7 @@
 	EM(rxrpc_reqack_retrans,		"RETRANS   ")	\
 	EM(rxrpc_reqack_slow_start,		"SLOW-START")	\
 	E_(rxrpc_reqack_small_txwin,		"SMALL-TXWN")
+/* ---- Must update size of stat_why_req_ack[] if more are added! */
 
 /*
  * Generate enums for tracing information.

net/rxrpc/ar-internal.h

@@ -107,6 +107,8 @@ struct rxrpc_net {
 	atomic_t		stat_tx_ack_skip;
 	atomic_t		stat_tx_acks[256];
 	atomic_t		stat_rx_acks[256];
+
+	atomic_t		stat_why_req_ack[8];
 };
 
 /*

net/rxrpc/output.c

@@ -430,6 +430,7 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
 	else
 		goto dont_set_request_ack;
 
+	rxrpc_inc_stat(call->rxnet, stat_why_req_ack[why]);
 	trace_rxrpc_req_ack(call->debug_id, sp->hdr.seq, why);
 	if (why != rxrpc_reqack_no_srv_last)
 		whdr.flags |= RXRPC_REQUEST_ACK;

net/rxrpc/proc.c

@@ -445,6 +445,18 @@ int rxrpc_stats_show(struct seq_file *seq, void *v)
 		   atomic_read(&rxnet->stat_rx_acks[RXRPC_ACK_PING_RESPONSE]),
 		   atomic_read(&rxnet->stat_rx_acks[RXRPC_ACK_DELAY]),
 		   atomic_read(&rxnet->stat_rx_acks[RXRPC_ACK_IDLE]));
+	seq_printf(seq,
+		   "Why-Req-A: acklost=%u already=%u mrtt=%u ortt=%u\n",
+		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_ack_lost]),
+		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_already_on]),
+		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_more_rtt]),
+		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_old_rtt]));
+	seq_printf(seq,
+		   "Why-Req-A: nolast=%u retx=%u slows=%u smtxw=%u\n",
+		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_no_srv_last]),
+		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_retrans]),
+		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_slow_start]),
+		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_small_txwin]));
 	seq_printf(seq,
 		   "Buffers  : txb=%u rxb=%u\n",
 		   atomic_read(&rxrpc_n_tx_skbs),
@@ -476,5 +488,7 @@ int rxrpc_stats_clear(struct file *file, char *buf, size_t size)
 	atomic_set(&rxnet->stat_tx_ack_skip, 0);
 	memset(&rxnet->stat_tx_acks, 0, sizeof(rxnet->stat_tx_acks));
 	memset(&rxnet->stat_rx_acks, 0, sizeof(rxnet->stat_rx_acks));
+
+	memset(&rxnet->stat_why_req_ack, 0, sizeof(rxnet->stat_why_req_ack));
 	return size;
 }