Re: [RFC PATCH net-next] tcp: add a tracepoint for tcp_listen_queue_drop

From: Jakub Kicinski
Date: Tue Jul 11 2023 - 22:36:17 EST


On Mon, 10 Jul 2023 21:34:52 -0700 Ivan Babrou wrote:
> There's already a way to count the overall numbers of queue overflows:
>
> $ sudo netstat -s | grep 'listen queue'
> 4 times the listen queue of a socket overflowed
>
> However, it's too coarse for monitoring and alerting when a user wants to
> track errors per socket and route alerts to people responsible for those
> sockets directly. For UDP there's udp_fail_queue_rcv_skb, which fills
> a similar need for UDP sockets. This patch adds a TCP equivalent.

Makes me want to revert your recent UDP tracepoint to be honest :(
We can play whack a mole like this. You said that kfree_skb fires
too often, why is that? Maybe it's an issue of someone using
kfree_skb() when they should be using consume_skb() ?