rxrpc: Don't transmit DELAY ACKs immediately on proposal

Don't transmit a DELAY ACK immediately on proposal when the Rx window is
rotated, but rather defer it to the work function.  This means that we have
a chance to queue/consume more received packets before we actually send the
DELAY ACK, or even cancel it entirely, thereby reducing the number of
packets transmitted.

We do, however, want to continue sending other types of packet immediately,
particularly REQUESTED ACKs, as they may be used for RTT calculation by the
other side.

Signed-off-by: David Howells <dhowells@redhat.com>

diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c
index 0b6609da80b7599d9a03d8bc58d07d159835c0d7..fad5f42a3abd333862f6585103bf31de9a6a9672 100644 (file)
--- a/net/rxrpc/recvmsg.c
+++ b/net/rxrpc/recvmsg.c
@@ -219,9 +219,9 @@ static void rxrpc_rotate_rx_window(struct rxrpc_call *call)
                    after_eq(top, call->ackr_seen + 2) ||
                    (hard_ack == top && after(hard_ack, call->ackr_consumed)))
                        rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, 0, serial,
-                                         true, false,
+                                         true, true,
                                          rxrpc_propose_ack_rotate_rx);
-               if (call->ackr_reason)
+               if (call->ackr_reason && call->ackr_reason != RXRPC_ACK_DELAY)
                        rxrpc_send_ack_packet(call, false);
        }
 }