Subject: Re: [RFC PATCH net-next] tcp: Add net.ipv4.tcp_purge_receive_queue sysctl

From: Jakub Kicinski <[email-masked]>
Date: Mon, 2 Mar 2026 16:22:51 -0800

On Mon, 2 Mar 2026 17:55:59 +0800 Leon Hwang wrote:
> On 26/2/26 09:43, Jakub Kicinski wrote:
> > On Wed, 25 Feb 2026 15:46:33 +0800 Leon Hwang wrote:  
> >> Issue:
> >> When a TCP socket in the CLOSE_WAIT state receives a RST packet, the
> >> current implementation does not clear the socket's receive queue. This
> >> causes SKBs in the queue to remain allocated until the socket is
> >> explicitly closed by the application. As a consequence:
> >>
> >> 1. The page pool pages held by these SKBs are not released.  
> > 
> > On what kernel version and driver are you observing this?  
> 
> # uname -r
> 6.19.0-061900-generic
> 
> # ethtool -i eth0
> driver: mlx5_core
> version: 6.19.0-061900-generic
> firmware-version: 26.43.2566 (MT_0000000531)

Okay... this kernel + driver should just patiently wait for the page
pool to go away. 

What is the actual, end user problem that you're trying to solve?
A few kB of data waiting to be freed is not a huge problem..