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authorYuchung Cheng <ycheng@google.com>2018-11-28 16:06:45 -0800
committerDavid S. Miller <davem@davemloft.net>2018-11-30 17:22:41 -0800
commite1561fe2dd69dc5dddd69bd73aa65355bdfb048b (patch)
tree40da17c4bfcd170c22ffd81e392f3f3c54407270 /net/ipv4/tcp_timer.c
parenttcp: fix SNMP under-estimation on failed retransmission (diff)
downloadlinux-dev-e1561fe2dd69dc5dddd69bd73aa65355bdfb048b.tar.xz
linux-dev-e1561fe2dd69dc5dddd69bd73aa65355bdfb048b.zip
tcp: fix SNMP TCP timeout under-estimation
Previously the SNMP TCPTIMEOUTS counter has inconsistent accounting: 1. It counts all SYN and SYN-ACK timeouts 2. It counts timeouts in other states except recurring timeouts and timeouts after fast recovery or disorder state. Such selective accounting makes analysis difficult and complicated. For example the monitoring system needs to collect many other SNMP counters to infer the total amount of timeout events. This patch makes TCPTIMEOUTS counter simply counts all the retransmit timeout (SYN or data or FIN). Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_timer.c')
-rw-r--r--net/ipv4/tcp_timer.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index 25efdae4368a..f87dbc78b6bc 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -484,11 +484,12 @@ void tcp_retransmit_timer(struct sock *sk)
goto out_reset_timer;
}
+ __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPTIMEOUTS);
if (tcp_write_timeout(sk))
goto out;
if (icsk->icsk_retransmits == 0) {
- int mib_idx;
+ int mib_idx = 0;
if (icsk->icsk_ca_state == TCP_CA_Recovery) {
if (tcp_is_sack(tp))
@@ -503,10 +504,9 @@ void tcp_retransmit_timer(struct sock *sk)
mib_idx = LINUX_MIB_TCPSACKFAILURES;
else
mib_idx = LINUX_MIB_TCPRENOFAILURES;
- } else {
- mib_idx = LINUX_MIB_TCPTIMEOUTS;
}
- __NET_INC_STATS(sock_net(sk), mib_idx);
+ if (mib_idx)
+ __NET_INC_STATS(sock_net(sk), mib_idx);
}
tcp_enter_loss(sk);