From 031afe4990a7c9dbff41a3a742c44d3e740ea0a1 Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Sat, 12 Oct 2013 10:16:27 -0700 Subject: tcp: fix incorrect ca_state in tail loss probe On receiving an ACK that covers the loss probe sequence, TLP immediately sets the congestion state to Open, even though some packets are not recovered and retransmisssion are on the way. The later ACks may trigger a WARN_ON check in step D of tcp_fastretrans_alert(), e.g., https://bugzilla.redhat.com/show_bug.cgi?id=989251 The fix is to follow the similar procedure in recovery by calling tcp_try_keep_open(). The sender switches to Open state if no packets are retransmissted. Otherwise it goes to Disorder and let subsequent ACKs move the state to Recovery or Open. Reported-By: Michael Sterrett Tested-By: Dormando Signed-off-by: Yuchung Cheng Acked-by: Neal Cardwell Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/ipv4/tcp_input.c') diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 113dc5f17d47..53974c7c04fe 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3291,7 +3291,7 @@ static void tcp_process_tlp_ack(struct sock *sk, u32 ack, int flag) tcp_init_cwnd_reduction(sk, true); tcp_set_ca_state(sk, TCP_CA_CWR); tcp_end_cwnd_reduction(sk); - tcp_set_ca_state(sk, TCP_CA_Open); + tcp_try_keep_open(sk); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPLOSSPROBERECOVERY); } -- cgit v1.2.3-55-g7522 From 02cf4ebd82ff0ac7254b88e466820a290ed8289a Mon Sep 17 00:00:00 2001 From: Neal Cardwell Date: Mon, 21 Oct 2013 15:40:19 -0400 Subject: tcp: initialize passive-side sk_pacing_rate after 3WHS For passive TCP connections, upon receiving the ACK that completes the 3WHS, make sure we set our pacing rate after we get our first RTT sample. On passive TCP connections, when we receive the ACK completing the 3WHS we do not take an RTT sample in tcp_ack(), but rather in tcp_synack_rtt_meas(). So upon receiving the ACK that completes the 3WHS, tcp_ack() leaves sk_pacing_rate at its initial value. Originally the initial sk_pacing_rate value was 0, so passive-side connections defaulted to sysctl_tcp_min_tso_segs (2 segs) in skbuffs made in the first RTT. With a default initial cwnd of 10 packets, this happened to be correct for RTTs 5ms or bigger, so it was hard to see problems in WAN or emulated WAN testing. Since 7eec4174ff ("pkt_sched: fq: fix non TCP flows pacing"), the initial sk_pacing_rate is 0xffffffff. So after that change, passive TCP connections were keeping this value (and using large numbers of segments per skbuff) until receiving an ACK for data. Signed-off-by: Neal Cardwell Cc: Eric Dumazet Cc: Yuchung Cheng Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/ipv4/tcp_input.c') diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 53974c7c04fe..a16b01b537ba 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5712,6 +5712,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, } else tcp_init_metrics(sk); + tcp_update_pacing_rate(sk); + /* Prevent spurious tcp_cwnd_restart() on first data packet */ tp->lsndtime = tcp_time_stamp; -- cgit v1.2.3-55-g7522