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Subject: Re: [PATCH net-next v13 0/5] tun/tap & vhost-net: apply qdisc
 backpressure on full ptr_ring to reduce TX drops
To: willemdebruijn.kernel@gmail.com, jasowangio@gmail.com, jasowang@redhat.com,
        andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com,
        kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, mst@redhat.com,
        eperezma@redhat.com, leiyang@redhat.com, stephen@networkplumber.org,
        jon@nutanix.com, brett@librecast.net, corbet@lwn.net,
        skhan@linuxfoundation.org, tim.gebauer@tu-dortmund.de,
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References: <20260730213639.726381-1-simon.schippers@tu-dortmund.de>
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From: Simon Schippers <simon.schippers@tu-dortmund.de>
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On 7/30/26 23:36, Simon Schippers wrote:
> This patch series deals with tun/tap & vhost-net which drop incoming
> SKBs whenever their internal ptr_ring buffer is full. Instead, with this
> patch series, the associated netdev queue is stopped, but only when the
> new IFF_BACKPRESSURE flag is set and a qdisc is attached. Without the
> flag, or if no qdisc is present, the existing behavior is preserved. The
> XDP transmit path is not affected. This patch series touches tun/tap and
> vhost-net, as they share common logic and must be updated together.
> Modifying only one of them would break the other.

Sashiko found valid regressions, even though the code stayed the same.

I will address them and send a v14 soon.