From 575ee7140dabe9b9c4f66f4f867039b97e548867 Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Mon, 30 Apr 2007 00:39:55 -0700 Subject: [TCP] FRTO: Delay skb available check until it's mandatory No new data is needed until the first ACK comes, so no need to check for application limitedness until then. Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 051f0f815f17..6b669898b197 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -1265,20 +1265,15 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ return flag; } -/* F-RTO can only be used if these conditions are satisfied: - * - there must be some unsent new data - * - the advertised window should allow sending it - * - TCP has never retransmitted anything other than head (SACK enhanced - * variant from Appendix B of RFC4138 is more robust here) +/* F-RTO can only be used if TCP has never retransmitted anything other than + * head (SACK enhanced variant from Appendix B of RFC4138 is more robust here) */ int tcp_use_frto(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; - if (!sysctl_tcp_frto || !tcp_send_head(sk) || - after(TCP_SKB_CB(tcp_send_head(sk))->end_seq, - tp->snd_una + tp->snd_wnd)) + if (!sysctl_tcp_frto) return 0; if (IsSackFrto()) @@ -2710,6 +2705,14 @@ static int tcp_process_frto(struct sock *sk, u32 prior_snd_una, int flag) } if (tp->frto_counter == 1) { + /* Sending of the next skb must be allowed or no FRTO */ + if (!tcp_send_head(sk) || + after(TCP_SKB_CB(tcp_send_head(sk))->end_seq, + tp->snd_una + tp->snd_wnd)) { + tcp_enter_frto_loss(sk, tp->frto_counter + 1, flag); + return 1; + } + tp->snd_cwnd = tcp_packets_in_flight(tp) + 2; tp->frto_counter = 2; return 1; -- cgit v1.2.3