From 92ee76b6d99bfcdab6162816c9025541ef7248eb Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Mon, 24 Nov 2008 21:26:56 -0800 Subject: tcp: Make shifting not clear the hints MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The earlier version was just very basic one which is "playing safe" by always clearing the hints. However, clearing of a hint is extremely costly operation with large windows, so it must be avoided at all cost whenever possible, there is a way with shifting too achieve not-clearing. Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'net') diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 97d57676b8e..e6291dde334 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -1379,6 +1379,11 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *prev, BUG_ON(!pcount); + /* Tweak before seqno plays */ + if (!tcp_is_fack(tp) && tcp_is_sack(tp) && tp->lost_skb_hint && + !before(TCP_SKB_CB(tp->lost_skb_hint)->seq, TCP_SKB_CB(skb)->seq)) + tp->lost_cnt_hint += pcount; + TCP_SKB_CB(prev)->end_seq += shifted; TCP_SKB_CB(skb)->seq += shifted; @@ -1408,8 +1413,6 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *prev, /* Difference in this won't matter, both ACKed by the same cumul. ACK */ TCP_SKB_CB(prev)->sacked |= (TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS); - tcp_clear_all_retrans_hints(tp); - if (skb->len > 0) { BUG_ON(!tcp_skb_pcount(skb)); return 0; @@ -1417,6 +1420,15 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *prev, /* Whole SKB was eaten :-) */ + if (skb == tp->retransmit_skb_hint) + tp->retransmit_skb_hint = prev; + if (skb == tp->scoreboard_skb_hint) + tp->scoreboard_skb_hint = prev; + if (skb == tp->lost_skb_hint) { + tp->lost_skb_hint = prev; + tp->lost_cnt_hint -= tcp_skb_pcount(prev); + } + TCP_SKB_CB(skb)->flags |= TCP_SKB_CB(prev)->flags; if (skb == tcp_highest_sack(sk)) tcp_advance_highest_sack(sk, skb); -- cgit v1.2.3