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[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 <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ilpo Järvinen 2007-04-30 00:39:55 -07:00 committed by David S. Miller
parent 157bfc2502
commit 575ee7140d
1 changed files with 11 additions and 8 deletions
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19
net/ipv4/tcp_input.c
View File

@ -1265,20 +1265,15 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
return flag; return flag;
} }
/* F-RTO can only be used if these conditions are satisfied: /* F-RTO can only be used if TCP has never retransmitted anything other than
* - there must be some unsent new data * head (SACK enhanced variant from Appendix B of RFC4138 is more robust here)
* - 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)
*/ */
int tcp_use_frto(struct sock *sk) int tcp_use_frto(struct sock *sk)
{ {
const struct tcp_sock *tp = tcp_sk(sk); const struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb; struct sk_buff *skb;
if (!sysctl_tcp_frto || !tcp_send_head(sk) || if (!sysctl_tcp_frto)
after(TCP_SKB_CB(tcp_send_head(sk))->end_seq,
tp->snd_una + tp->snd_wnd))
return 0; return 0;
if (IsSackFrto()) 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) { 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->snd_cwnd = tcp_packets_in_flight(tp) + 2;
tp->frto_counter = 2; tp->frto_counter = 2;
return 1; return 1;