From 1b6d427bb7eb69e6dc4f194a5b0f4a382a16ff82 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ilpo=20J=C3=A4rvinen?= Date: Thu, 9 Aug 2007 14:53:36 +0300 Subject: [PATCH] [TCP]: Reduce sacked_out with reno when purging write_queue MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Previously TCP had a transitional state during which reno counted segments that are already below the current window into sacked_out, which is now prevented. In addition, re-try now the unconditional S+L skb catching. This approach conservatively calls just remove_sack and leaves reset_sack() calls alone. The best solution to the whole problem would be to first calculate the new sacked_out fully (this patch does not move reno_sack_reset calls from original sites and thus does not implement this). However, that would require very invasive change to fastretrans_alert (perhaps even slicing it to two halves). Alternatively, all callers of tcp_packets_in_flight (i.e., users that depend on sacked_out) should be postponed until the new sacked_out has been calculated but it isn't any simpler alternative. Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- include/net/tcp.h | 3 +-- net/ipv4/tcp_input.c | 15 +++++++-------- 2 files changed, 8 insertions(+), 10 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 7042c32085f..064c92fe00d 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -759,8 +759,7 @@ static inline __u32 tcp_current_ssthresh(const struct sock *sk) } /* Use define here intentionally to get BUG_ON location shown at the caller */ -#define tcp_verify_left_out(tp) \ - BUG_ON(tp->rx_opt.sack_ok && (tcp_left_out(tp) > tp->packets_out)) +#define tcp_verify_left_out(tp) BUG_ON(tcp_left_out(tp) > tp->packets_out) extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh); extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst); diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index bf4fc3516fb..f8af018dd22 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2187,7 +2187,7 @@ static void tcp_mtup_probe_success(struct sock *sk, struct sk_buff *skb) * tcp_xmit_retransmit_queue(). */ static void -tcp_fastretrans_alert(struct sock *sk, int prior_packets, int flag) +tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag) { struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); @@ -2273,12 +2273,8 @@ tcp_fastretrans_alert(struct sock *sk, int prior_packets, int flag) if (!(flag & FLAG_SND_UNA_ADVANCED)) { if (IsReno(tp) && is_dupack) tcp_add_reno_sack(sk); - } else { - int acked = prior_packets - tp->packets_out; - if (IsReno(tp)) - tcp_remove_reno_sacks(sk, acked); - do_lost = tcp_try_undo_partial(sk, acked); - } + } else + do_lost = tcp_try_undo_partial(sk, pkts_acked); break; case TCP_CA_Loss: if (flag&FLAG_DATA_ACKED) @@ -2577,6 +2573,9 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p) tcp_ack_update_rtt(sk, acked, seq_rtt); tcp_ack_packets_out(sk); + if (IsReno(tp)) + tcp_remove_reno_sacks(sk, pkts_acked); + if (ca_ops->pkts_acked) { s32 rtt_us = -1; @@ -2927,7 +2926,7 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag) if ((flag & FLAG_DATA_ACKED) && !frto_cwnd && tcp_may_raise_cwnd(sk, flag)) tcp_cong_avoid(sk, ack, prior_in_flight, 0); - tcp_fastretrans_alert(sk, prior_packets, flag); + tcp_fastretrans_alert(sk, prior_packets - tp->packets_out, flag); } else { if ((flag & FLAG_DATA_ACKED) && !frto_cwnd) tcp_cong_avoid(sk, ack, prior_in_flight, 1); -- 2.41.1