From patchwork Sat Sep 20 17:52:31 2008 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [net-next, 13/15] tcp: don't clear retransmit_skb_hint when not necessary From: =?utf-8?q?Ilpo_J=C3=A4rvinen?= X-Patchwork-Id: 731 Message-Id: <1221933153-11874-14-git-send-email-ilpo.jarvinen@helsinki.fi> To: David Miller Cc: netdev@vger.kernel.org, "=?utf-8?q?Ilpo=20J=E4rvinen?=" Date: Sat, 20 Sep 2008 20:52:31 +0300 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 --- include/net/tcp.h | 7 ++++++- net/ipv4/tcp_input.c | 4 +++- net/ipv4/tcp_output.c | 8 +++++--- 3 files changed, 14 insertions(+), 5 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 10f838e..2d6b140 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1036,10 +1036,15 @@ 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 8a6dec8..f217b4f 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 63686bf..01fb610 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -748,7 +748,7 @@ 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; @@ -1821,7 +1821,9 @@ 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); } @@ -1855,7 +1857,7 @@ void tcp_simple_retransmit(struct sock *sk) } } - tcp_clear_all_retrans_hints(tp); + tcp_clear_retrans_hints_partial(tp); if (!lost) return;