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authorYousuk Seung <ysseung@google.com>2017-12-07 13:41:34 -0800
committerDavid S. Miller <davem@davemloft.net>2017-12-08 10:07:02 -0500
commitd4761754b4fb2ef8d9a1e9d121c4bec84e1fe292 (patch)
tree5a55983a564530e094904c68883a4ce77b69724b /include
parent195bd525d5f6e338b948d9a6b25bfaae86291353 (diff)
tcp: invalidate rate samples during SACK reneging
Mark tcp_sock during a SACK reneging event and invalidate rate samples while marked. Such rate samples may overestimate bw by including packets that were SACKed before reneging. < ack 6001 win 10000 sack 7001:38001 < ack 7001 win 0 sack 8001:38001 // Reneg detected > seq 7001:8001 // RTO, SACK cleared. < ack 38001 win 10000 In above example the rate sample taken after the last ack will count 7001-38001 as delivered while the actual delivery rate likely could be much lower i.e. 7001-8001. This patch adds a new field tcp_sock.sack_reneg and marks it when we declare SACK reneging and entering TCP_CA_Loss, and unmarks it after the last rate sample was taken before moving back to TCP_CA_Open. This patch also invalidates rate samples taken while tcp_sock.is_sack_reneg is set. Fixes: b9f64820fb22 ("tcp: track data delivery rate for a TCP connection") Signed-off-by: Yousuk Seung <ysseung@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Priyaranjan Jha <priyarjha@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/linux/tcp.h3
-rw-r--r--include/net/tcp.h2
2 files changed, 3 insertions, 2 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index df5d97a85e1a..ca4a6361389b 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -224,7 +224,8 @@ struct tcp_sock {
rate_app_limited:1, /* rate_{delivered,interval_us} limited? */
fastopen_connect:1, /* FASTOPEN_CONNECT sockopt */
fastopen_no_cookie:1, /* Allow send/recv SYN+data without a cookie */
- unused:3;
+ is_sack_reneg:1, /* in recovery from loss with SACK reneg? */
+ unused:2;
u8 nonagle : 4,/* Disable Nagle algorithm? */
thin_lto : 1,/* Use linear timeouts for thin streams */
unused1 : 1,
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 6998707e81f3..6da880d2f022 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1055,7 +1055,7 @@ void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb);
void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb,
struct rate_sample *rs);
void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost,
- struct rate_sample *rs);
+ bool is_sack_reneg, struct rate_sample *rs);
void tcp_rate_check_app_limited(struct sock *sk);
/* These functions determine how the current flow behaves in respect of SACK