Commit aeeecb88 authored Nov 28, 2021 by Menglong Dong Committed by David S. Miller Nov 29, 2021

net: snmp: add statistics for tcp small queue check



Once tcp small queue check failed in tcp_small_queue_check(), the
throughput of tcp will be limited, and it's hard to distinguish
whether it is out of tcp congestion control.

Add statistics of LINUX_MIB_TCPSMALLQUEUEFAILURE for this scene.

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent e9538f82

include/uapi/linux/snmp.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -292,6 +292,7 @@ enum
		LINUX_MIB_TCPDSACKIGNOREDDUBIOUS, /* TCPDSACKIgnoredDubious */
		LINUX_MIB_TCPMIGRATEREQSUCCESS, /* TCPMigrateReqSuccess */
		LINUX_MIB_TCPMIGRATEREQFAILURE, /* TCPMigrateReqFailure */
		LINUX_MIB_TCPSMALLQUEUEFAILURE, /* TCPSmallQueueFailure */
		__LINUX_MIB_MAX
		};

net/ipv4/proc.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -297,6 +297,7 @@ static const struct snmp_mib snmp4_net_list[] = {
		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
		};

net/ipv4/tcp_output.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -2524,9 +2524,12 @@ static bool tcp_small_queue_check(struct sock sk, const struct sk_buff skb,
		* test again the condition.
		*/
		smp_mb__after_atomic();
		if (refcount_read(&sk->sk_wmem_alloc) > limit)
		if (refcount_read(&sk->sk_wmem_alloc) > limit) {
		NET_INC_STATS(sock_net(sk),
		LINUX_MIB_TCPSMALLQUEUEFAILURE);
		return true;
		}
		}
		return false;
		}