tcp: add LINUX_MIB_TCPRETRANSFAIL counter

It might be useful to get a counter of failed tcp_retransmit_skb() calls. Reported-by: Satoru Moriya <satoru.moriya@hds.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
git-mirror · Jan 26, 2012 · 09e9b81 · 09e9b81
1 parent bb349bb
commit 09e9b81
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Showing 3 changed files with 5 additions and 1 deletion.
diff --git a/include/linux/snmp.h b/include/linux/snmp.h
@@ -232,6 +232,7 @@ enum
 	LINUX_MIB_TCPTIMEWAITOVERFLOW,		/* TCPTimeWaitOverflow */
 	LINUX_MIB_TCPREQQFULLDOCOOKIES,		/* TCPReqQFullDoCookies */
 	LINUX_MIB_TCPREQQFULLDROP,		/* TCPReqQFullDrop */
+	LINUX_MIB_TCPRETRANSFAIL,		/* TCPRetransFail */
 	__LINUX_MIB_MAX
 };
 

diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
@@ -256,6 +256,7 @@ static const struct snmp_mib snmp4_net_list[] = {
 	SNMP_MIB_ITEM("TCPTimeWaitOverflow", LINUX_MIB_TCPTIMEWAITOVERFLOW),
 	SNMP_MIB_ITEM("TCPReqQFullDoCookies", LINUX_MIB_TCPREQQFULLDOCOOKIES),
 	SNMP_MIB_ITEM("TCPReqQFullDrop", LINUX_MIB_TCPREQQFULLDROP),
+	SNMP_MIB_ITEM("TCPRetransFail", LINUX_MIB_TCPRETRANSFAIL),
 	SNMP_MIB_SENTINEL
 };
 

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
@@ -2308,8 +2308,10 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
 		if (sacked & (TCPCB_SACKED_ACKED|TCPCB_SACKED_RETRANS))
 			continue;
 
-		if (tcp_retransmit_skb(sk, skb))
+		if (tcp_retransmit_skb(sk, skb)) {
+			NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPRETRANSFAIL);
 			return;
+		}
 		NET_INC_STATS_BH(sock_net(sk), mib_idx);
 
 		if (inet_csk(sk)->icsk_ca_state == TCP_CA_Recovery)