diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index f7f559204b87..578b8038b211 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -521,6 +521,7 @@
 #define rxrpc_req_ack_traces \
 	EM(rxrpc_reqack_ack_lost,		"ACK-LOST  ")	\
 	EM(rxrpc_reqack_app_stall,		"APP-STALL ")	\
+	EM(rxrpc_reqack_jumbo_win,		"JUMBO-WIN ")	\
 	EM(rxrpc_reqack_more_rtt,		"MORE-RTT  ")	\
 	EM(rxrpc_reqack_no_srv_last,		"NO-SRVLAST")	\
 	EM(rxrpc_reqack_old_rtt,		"OLD-RTT   ")	\
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 36d6ca0d1089..96ecb83c9071 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -117,7 +117,7 @@ struct rxrpc_net {
 	atomic_t		stat_tx_jumbo[10];
 	atomic_t		stat_rx_jumbo[10];
 
-	atomic_t		stat_why_req_ack[8];
+	atomic_t		stat_why_req_ack[9];
 
 	atomic_t		stat_io_loop;
 };
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index d70db367e358..870e59bf06af 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -479,6 +479,8 @@ static size_t rxrpc_prepare_data_subpacket(struct rxrpc_call *call,
 		why = rxrpc_reqack_old_rtt;
 	else if (!last && !after(READ_ONCE(call->send_top), txb->seq))
 		why = rxrpc_reqack_app_stall;
+	else if (call->tx_winsize <= (2 * req->n) || call->cong_cwnd <= (2 * req->n))
+		why = rxrpc_reqack_jumbo_win;
 	else
 		goto dont_set_request_ack;
 
diff --git a/net/rxrpc/proc.c b/net/rxrpc/proc.c
index 59292f7f9205..7755fca5beb8 100644
--- a/net/rxrpc/proc.c
+++ b/net/rxrpc/proc.c
@@ -518,11 +518,12 @@ int rxrpc_stats_show(struct seq_file *seq, void *v)
 		   atomic_read(&rxnet->stat_rx_acks[RXRPC_ACK_IDLE]),
 		   atomic_read(&rxnet->stat_rx_acks[0]));
 	seq_printf(seq,
-		   "Why-Req-A: acklost=%u mrtt=%u ortt=%u stall=%u\n",
+		   "Why-Req-A: acklost=%u mrtt=%u ortt=%u stall=%u jwin=%u\n",
 		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_ack_lost]),
 		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_more_rtt]),
 		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_old_rtt]),
-		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_app_stall]));
+		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_app_stall]),
+		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_jumbo_win]));
 	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]),