Revert "net: snmp: add statistics for tcp small queue check"
This reverts commit aeeecb889165617a841e939117f9a8095d0e7d80.
The new SNMP variable (TCPSmallQueueFailure) can be incremented
for good reasons, even on a 100Gbit single TCP_STREAM flow.
If we really wanted to ease driver debugging [1], this would
require something more sophisticated.
[1] Usually, if a driver is delaying TX completions too much,
this can lead to stalls in TCP output. Various work arounds
have been used in the past, like skb_orphan() in ndo_start_xmit().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Menglong Dong <imagedong@tencent.com>
Link: https://lore.kernel.org/r/20211201033246.2826224-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h
index e32ec69..904909d 100644
--- a/include/uapi/linux/snmp.h
+++ b/include/uapi/linux/snmp.h
@@ -292,7 +292,6 @@
LINUX_MIB_TCPDSACKIGNOREDDUBIOUS, /* TCPDSACKIgnoredDubious */
LINUX_MIB_TCPMIGRATEREQSUCCESS, /* TCPMigrateReqSuccess */
LINUX_MIB_TCPMIGRATEREQFAILURE, /* TCPMigrateReqFailure */
- LINUX_MIB_TCPSMALLQUEUEFAILURE, /* TCPSmallQueueFailure */
__LINUX_MIB_MAX
};
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index 43b7a77..f30273a 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -297,7 +297,6 @@
SNMP_MIB_ITEM("TCPDSACKIgnoredDubious", LINUX_MIB_TCPDSACKIGNOREDDUBIOUS),
SNMP_MIB_ITEM("TCPMigrateReqSuccess", LINUX_MIB_TCPMIGRATEREQSUCCESS),
SNMP_MIB_ITEM("TCPMigrateReqFailure", LINUX_MIB_TCPMIGRATEREQFAILURE),
- SNMP_MIB_ITEM("TCPSmallQueueFailure", LINUX_MIB_TCPSMALLQUEUEFAILURE),
SNMP_MIB_SENTINEL
};
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index c4ab6c8..5079832 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2524,11 +2524,8 @@
* test again the condition.
*/
smp_mb__after_atomic();
- if (refcount_read(&sk->sk_wmem_alloc) > limit) {
- NET_INC_STATS(sock_net(sk),
- LINUX_MIB_TCPSMALLQUEUEFAILURE);
+ if (refcount_read(&sk->sk_wmem_alloc) > limit)
return true;
- }
}
return false;
}
