From f82b681a511f4d61069e9586a9cf97bdef371ef3 Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Mon, 13 Jul 2015 12:10:20 -0700 Subject: [PATCH] tcp: don't use F-RTO on non-recurring timeouts Currently F-RTO may repeatedly send new data packets on non-recurring timeouts in CA_Loss mode. This is a bug because F-RTO (RFC5682) should only be used on either new recovery or recurring timeouts. This exacerbates the recovery progress during frequent timeout & repair, because we prioritize sending new data packets instead of repairing the holes when the bandwidth is already scarce. Fix it by correcting the test of a new recovery episode. Signed-off-by: Yuchung Cheng Signed-off-by: Neal Cardwell Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 684f095d196e..728f5b3d3c64 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -1917,14 +1917,13 @@ void tcp_enter_loss(struct sock *sk) const struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; - bool new_recovery = false; + bool new_recovery = icsk->icsk_ca_state < TCP_CA_Recovery; bool is_reneg; /* is receiver reneging on SACKs? */ /* Reduce ssthresh if it has not yet been made inside this window. */ if (icsk->icsk_ca_state <= TCP_CA_Disorder || !after(tp->high_seq, tp->snd_una) || (icsk->icsk_ca_state == TCP_CA_Loss && !icsk->icsk_retransmits)) { - new_recovery = true; tp->prior_ssthresh = tcp_current_ssthresh(sk); tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk); tcp_ca_event(sk, CA_EVENT_LOSS); -- 2.20.1