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authorIlpo Järvinen <ilpo.jarvinen@helsinki.fi>2008-09-20 21:25:15 -0700
committerDavid S. Miller <davem@davemloft.net>2008-09-20 21:25:15 -0700
commitef9da47c7cc64d69526331f315e76b5680d4048f (patch)
tree97407b83c7c339dbe1fd0948c30f35e1680562ec
parentf0ceb0ed86b4792a4ed9d3438f5f7572e48f9803 (diff)
tcp: don't clear retransmit_skb_hint when not necessary
Most importantly avoid doing it with cumulative ACK. Not clearing means that we no longer need n^2 processing in resolution of each fast recovery. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/tcp.h7
-rw-r--r--net/ipv4/tcp_input.c4
-rw-r--r--net/ipv4/tcp_output.c8
3 files changed, 14 insertions, 5 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 220f54cf42ec..ea815723d414 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1037,10 +1037,15 @@ static inline void tcp_mib_init(struct net *net)
}
/* from STCP */
-static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
+static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)
{
tp->lost_skb_hint = NULL;
tp->scoreboard_skb_hint = NULL;
+}
+
+static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)
+{
+ tcp_clear_retrans_hints_partial(tp);
tp->retransmit_skb_hint = NULL;
}
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index d017aed6edd7..44a4fffc2cc3 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2925,7 +2925,9 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets)
tcp_unlink_write_queue(skb, sk);
sk_wmem_free_skb(sk, skb);
- tcp_clear_all_retrans_hints(tp);
+ tcp_clear_retrans_hints_partial(tp);
+ if (skb == tp->retransmit_skb_hint)
+ tp->retransmit_skb_hint = NULL;
}
if (skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index f900fae8b87e..239cea7b6c0e 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -750,7 +750,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
BUG_ON(len > skb->len);
- tcp_clear_all_retrans_hints(tp);
+ tcp_clear_retrans_hints_partial(tp);
nsize = skb_headlen(skb) - len;
if (nsize < 0)
nsize = 0;
@@ -1823,7 +1823,9 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb,
tp->packets_out -= tcp_skb_pcount(next_skb);
/* changed transmit queue under us so clear hints */
- tcp_clear_all_retrans_hints(tp);
+ tcp_clear_retrans_hints_partial(tp);
+ if (next_skb == tp->retransmit_skb_hint)
+ tp->retransmit_skb_hint = skb;
sk_wmem_free_skb(sk, next_skb);
}
@@ -1853,7 +1855,7 @@ void tcp_simple_retransmit(struct sock *sk)
}
}
- tcp_clear_all_retrans_hints(tp);
+ tcp_clear_retrans_hints_partial(tp);
if (prior_lost == tp->lost_out)
return;