---

yaml --- r: 368232 b: refs/heads/master c: 9b717a8 h: refs/heads/master v: v3
git-mirror · Mar 12, 2013 · b623c9b · b623c9b
1 parent b3767f8
commit b623c9b
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Showing 8 changed files with 55 additions and 1 deletion.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 6ba8a3b19e764b6a65e4030ab0999be50c291e6c
+refs/heads/master: 9b717a8d245075ffb8e95a2dfb4ee97ce4747457
diff --git a/trunk/include/linux/tcp.h b/trunk/include/linux/tcp.h
@@ -204,6 +204,7 @@ struct tcp_sock {
 		syn_data:1,	/* SYN includes data */
 		syn_fastopen:1,	/* SYN includes Fast Open option */
 		syn_data_acked:1;/* data in SYN is acked by SYN-ACK */
+	u32	tlp_high_seq;	/* snd_nxt at the time of TLP retransmit. */
 
 /* RTT measurement */
 	u32	srtt;		/* smoothed round trip time << 3	*/

diff --git a/trunk/include/uapi/linux/snmp.h b/trunk/include/uapi/linux/snmp.h
@@ -203,6 +203,7 @@ enum
 	LINUX_MIB_TCPSLOWSTARTRETRANS,		/* TCPSlowStartRetrans */
 	LINUX_MIB_TCPTIMEOUTS,			/* TCPTimeouts */
 	LINUX_MIB_TCPLOSSPROBES,		/* TCPLossProbes */
+	LINUX_MIB_TCPLOSSPROBERECOVERY,		/* TCPLossProbeRecovery */
 	LINUX_MIB_TCPRENORECOVERYFAIL,		/* TCPRenoRecoveryFail */
 	LINUX_MIB_TCPSACKRECOVERYFAIL,		/* TCPSackRecoveryFail */
 	LINUX_MIB_TCPSCHEDULERFAILED,		/* TCPSchedulerFailed */

diff --git a/trunk/net/ipv4/proc.c b/trunk/net/ipv4/proc.c
@@ -225,6 +225,7 @@ static const struct snmp_mib snmp4_net_list[] = {
 	SNMP_MIB_ITEM("TCPSlowStartRetrans", LINUX_MIB_TCPSLOWSTARTRETRANS),
 	SNMP_MIB_ITEM("TCPTimeouts", LINUX_MIB_TCPTIMEOUTS),
 	SNMP_MIB_ITEM("TCPLossProbes", LINUX_MIB_TCPLOSSPROBES),
+	SNMP_MIB_ITEM("TCPLossProbeRecovery", LINUX_MIB_TCPLOSSPROBERECOVERY),
 	SNMP_MIB_ITEM("TCPRenoRecoveryFail", LINUX_MIB_TCPRENORECOVERYFAIL),
 	SNMP_MIB_ITEM("TCPSackRecoveryFail", LINUX_MIB_TCPSACKRECOVERYFAIL),
 	SNMP_MIB_ITEM("TCPSchedulerFailed", LINUX_MIB_TCPSCHEDULERFAILED),

diff --git a/trunk/net/ipv4/tcp_input.c b/trunk/net/ipv4/tcp_input.c
@@ -2682,6 +2682,7 @@ static void tcp_init_cwnd_reduction(struct sock *sk, const bool set_ssthresh)
 	struct tcp_sock *tp = tcp_sk(sk);
 
 	tp->high_seq = tp->snd_nxt;
+	tp->tlp_high_seq = 0;
 	tp->snd_cwnd_cnt = 0;
 	tp->prior_cwnd = tp->snd_cwnd;
 	tp->prr_delivered = 0;
@@ -3569,6 +3570,38 @@ static void tcp_send_challenge_ack(struct sock *sk)
 	}
 }
 
+/* This routine deals with acks during a TLP episode.
+ * Ref: loss detection algorithm in draft-dukkipati-tcpm-tcp-loss-probe.
+ */
+static void tcp_process_tlp_ack(struct sock *sk, u32 ack, int flag)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+	bool is_tlp_dupack = (ack == tp->tlp_high_seq) &&
+			     !(flag & (FLAG_SND_UNA_ADVANCED |
+				       FLAG_NOT_DUP | FLAG_DATA_SACKED));
+
+	/* Mark the end of TLP episode on receiving TLP dupack or when
+	 * ack is after tlp_high_seq.
+	 */
+	if (is_tlp_dupack) {
+		tp->tlp_high_seq = 0;
+		return;
+	}
+
+	if (after(ack, tp->tlp_high_seq)) {
+		tp->tlp_high_seq = 0;
+		/* Don't reduce cwnd if DSACK arrives for TLP retrans. */
+		if (!(flag & FLAG_DSACKING_ACK)) {
+			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);
+			NET_INC_STATS_BH(sock_net(sk),
+					 LINUX_MIB_TCPLOSSPROBERECOVERY);
+		}
+	}
+}
+
 /* This routine deals with incoming acks, but not outgoing ones. */
 static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 {
@@ -3676,6 +3709,9 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 			tcp_cong_avoid(sk, ack, prior_in_flight);
 	}
 
+	if (tp->tlp_high_seq)
+		tcp_process_tlp_ack(sk, ack, flag);
+
 	if ((flag & FLAG_FORWARD_PROGRESS) || !(flag & FLAG_NOT_DUP)) {
 		struct dst_entry *dst = __sk_dst_get(sk);
 		if (dst)
@@ -3697,6 +3733,9 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	 */
 	if (tcp_send_head(sk))
 		tcp_ack_probe(sk);
+
+	if (tp->tlp_high_seq)
+		tcp_process_tlp_ack(sk, ack, flag);
 	return 1;
 
 invalid_ack:

diff --git a/trunk/net/ipv4/tcp_minisocks.c b/trunk/net/ipv4/tcp_minisocks.c
@@ -440,6 +440,7 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req,
 		newtp->fackets_out = 0;
 		newtp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
 		tcp_enable_early_retrans(newtp);
+		newtp->tlp_high_seq = 0;
 
 		/* So many TCP implementations out there (incorrectly) count the
 		 * initial SYN frame in their delayed-ACK and congestion control

diff --git a/trunk/net/ipv4/tcp_output.c b/trunk/net/ipv4/tcp_output.c
@@ -2132,6 +2132,7 @@ bool tcp_schedule_loss_probe(struct sock *sk)
  */
 void tcp_send_loss_probe(struct sock *sk)
 {
+	struct tcp_sock *tp = tcp_sk(sk);
 	struct sk_buff *skb;
 	int pcount;
 	int mss = tcp_current_mss(sk);
@@ -2142,6 +2143,10 @@ void tcp_send_loss_probe(struct sock *sk)
 		goto rearm_timer;
 	}
 
+	/* At most one outstanding TLP retransmission. */
+	if (tp->tlp_high_seq)
+		goto rearm_timer;
+
 	/* Retransmit last segment. */
 	skb = tcp_write_queue_tail(sk);
 	if (WARN_ON(!skb))
@@ -2164,6 +2169,10 @@ void tcp_send_loss_probe(struct sock *sk)
 	if (skb->len > 0)
 		err = __tcp_retransmit_skb(sk, skb);
 
+	/* Record snd_nxt for loss detection. */
+	if (likely(!err))
+		tp->tlp_high_seq = tp->snd_nxt;
+
 rearm_timer:
 	inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
 				  inet_csk(sk)->icsk_rto,

diff --git a/trunk/net/ipv4/tcp_timer.c b/trunk/net/ipv4/tcp_timer.c
@@ -356,6 +356,8 @@ void tcp_retransmit_timer(struct sock *sk)
 
 	WARN_ON(tcp_write_queue_empty(sk));
 
+	tp->tlp_high_seq = 0;
+
 	if (!tp->snd_wnd && !sock_flag(sk, SOCK_DEAD) &&
 	    !((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))) {
 		/* Receiver dastardly shrinks window. Our retransmits