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authorEric Dumazet <edumazet@google.com>2021-11-30 19:32:46 -0800
committerJakub Kicinski <kuba@kernel.org>2021-12-01 19:06:09 -0800
commitce8299b6f76f28326fedce2b4da90888bd97eab2 (patch)
treeee9c848444134a92a77dfab024e3c7b6c14183e2
parentnet: mvneta: program 1ms autonegotiation clock divisor (diff)
downloadlinux-dev-ce8299b6f76f28326fedce2b4da90888bd97eab2.tar.xz
linux-dev-ce8299b6f76f28326fedce2b4da90888bd97eab2.zip
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>
-rw-r--r--include/uapi/linux/snmp.h1
-rw-r--r--net/ipv4/proc.c1
-rw-r--r--net/ipv4/tcp_output.c5
3 files changed, 1 insertions, 6 deletions
diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h
index e32ec6932e82..904909d020e2 100644
--- a/include/uapi/linux/snmp.h
+++ b/include/uapi/linux/snmp.h
@@ -292,7 +292,6 @@ enum
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 43b7a77cd6b4..f30273afb539 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -297,7 +297,6 @@ 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
};
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index c4ab6c8f0c77..5079832af5c1 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2524,11 +2524,8 @@ 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) {
- NET_INC_STATS(sock_net(sk),
- LINUX_MIB_TCPSMALLQUEUEFAILURE);
+ if (refcount_read(&sk->sk_wmem_alloc) > limit)
return true;
- }
}
return false;
}