From patchwork Sat Sep 20 21:47:58 2008 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [PATCHv2, net-next, 15/15] tcp: back retransmit_high when it over-estimated Date: Sat, 20 Sep 2008 11:47:58 -0000 From: =?utf-8?q?Ilpo_J=C3=A4rvinen?= X-Patchwork-Id: 747 Message-Id: <1221947278-16715-16-git-send-email-ilpo.jarvinen@helsinki.fi> To: David Miller Cc: netdev@vger.kernel.org, "=?utf-8?q?Ilpo=20J=E4rvinen?=" If lost skb is sacked, we might have nothing to retransmit as high as the retransmit_high is pointing to, so place it lower to avoid unnecessary walking. This is mainly for the case where high L'ed skbs gets sacked. Signed-off-by: Ilpo Järvinen --- net/ipv4/tcp_output.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 63b9ce1..b28eeb0 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2033,16 +2033,22 @@ void tcp_xmit_retransmit_queue(struct sock *sk) struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; struct sk_buff *hole = NULL; + u32 last_lost; int mib_idx; int fwd_rexmitting = 0; if (!tp->lost_out) tp->retransmit_high = tp->snd_una; - if (tp->retransmit_skb_hint) + if (tp->retransmit_skb_hint) { skb = tp->retransmit_skb_hint; - else + last_lost = TCP_SKB_CB(skb)->end_seq; + if (after(last_lost, tp->retransmit_high)) + last_lost = tp->retransmit_high; + } else { skb = tcp_write_queue_head(sk); + last_lost = tp->snd_una; + } /* First pass: retransmit lost packets. */ tcp_for_write_queue_from(skb, sk) { @@ -2071,6 +2077,7 @@ begin_fwd: mib_idx = LINUX_MIB_TCPFORWARDRETRANS; } else if (!before(TCP_SKB_CB(skb)->seq, tp->retransmit_high)) { + tp->retransmit_high = last_lost; if (!tcp_can_forward_retransmit(sk)) break; /* Backtrack if necessary to non-L'ed skb */ @@ -2087,6 +2094,7 @@ begin_fwd: continue; } else { + last_lost = TCP_SKB_CB(skb)->end_seq; if (icsk->icsk_ca_state != TCP_CA_Loss) mib_idx = LINUX_MIB_TCPFASTRETRANS; else