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authorYuchung Cheng <ycheng@google.com>2012-05-02 13:30:04 +0000
committerDavid S. Miller <davem@davemloft.net>2012-05-02 20:56:10 -0400
commit750ea2bafa55aaed208b2583470ecd7122225634 (patch)
tree7656d7697566b0cecc7fbbdd8dbae288bca6d7e3 /include/net/tcp.h
parenteed530b6c67624db3f2cf477bac7c4d005d8f7ba (diff)
downloadlwn-750ea2bafa55aaed208b2583470ecd7122225634.tar.gz
lwn-750ea2bafa55aaed208b2583470ecd7122225634.zip
tcp: early retransmit: delayed fast retransmit
Implementing the advanced early retransmit (sysctl_tcp_early_retrans==2). Delays the fast retransmit by an interval of RTT/4. We borrow the RTO timer to implement the delay. If we receive another ACK or send a new packet, the timer is cancelled and restored to original RTO value offset by time elapsed. When the delayed-ER timer fires, we enter fast recovery and perform fast retransmit. Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/tcp.h')
-rw-r--r--include/net/tcp.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 685437a16c97..5283aa4bfa23 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -500,6 +500,8 @@ extern void tcp_send_delayed_ack(struct sock *sk);
/* tcp_input.c */
extern void tcp_cwnd_application_limited(struct sock *sk);
+extern void tcp_resume_early_retransmit(struct sock *sk);
+extern void tcp_rearm_rto(struct sock *sk);
/* tcp_timer.c */
extern void tcp_init_xmit_timers(struct sock *);
@@ -805,6 +807,7 @@ static inline void tcp_enable_early_retrans(struct tcp_sock *tp)
{
tp->do_early_retrans = sysctl_tcp_early_retrans &&
!sysctl_tcp_thin_dupack && sysctl_tcp_reordering == 3;
+ tp->early_retrans_delayed = 0;
}
static inline void tcp_disable_early_retrans(struct tcp_sock *tp)