[PATCH net-next 9/9] rxrpc: Reduce the number of PING ACKs sent [ver #2]

[David Howells]

We don't want to send a PING ACK for every new incoming call as that just
adds to the network traffic.  Instead, we send a PING ACK to the first
three that we receive and then once per second thereafter.

This could probably be made adjustable in future.

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

 net/rxrpc/call_event.c |    2 +-
 net/rxrpc/input.c      |    7 +++++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index adb2ec61e21f..6e2ea8f4ae75 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -142,7 +142,7 @@ static void rxrpc_resend(struct rxrpc_call *call)
        struct rxrpc_skb_priv *sp;
        struct sk_buff *skb;
        rxrpc_seq_t cursor, seq, top;
-       ktime_t now = ktime_get_real(), max_age, oldest, resend_at;
+       ktime_t now = ktime_get_real(), max_age, oldest,  resend_at;
        int ix;
        u8 annotation, anno_type;
 
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index c121949de3c8..cbb5d53f09d7 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -44,9 +44,12 @@ static void rxrpc_send_ping(struct rxrpc_call *call, struct 
sk_buff *skb,
                            int skew)
 {
        struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+       ktime_t now = skb->tstamp;
 
-       rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
-                         true, true);
+       if (call->peer->rtt_usage < 3 ||
+           ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), now))
+               rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
+                                 true, true);
 }
 
 /*