Re: [PATCH net-next v2 00/14] tcp: preserve receive-window accounting across ratio drift

[Paolo Abeni]

On 3/14/26 9:13 PM, atwellwea@xxxxxxxxx wrote:
> From: Wesley Atwell <atwellwea@xxxxxxxxx>
> 
> This series keeps sender-visible TCP receive-window accounting tied to the
> scaling basis that was in force when the window was advertised, even if
> later receive-side truesize inflation lowers scaling_ratio or the live
> receive window retracts below the largest right edge already exposed to the
> sender.
> 
> After the receive-window retraction changes, the receive path needs to keep
> track of two related pieces of sender-visible state:
> 
>   1. the live advertised receive window
>   2. the maximum advertised right edge and the basis it was exposed with
> 
> This repost snapshots both, uses them to repair receive-buffer backing when
> ratio drift would otherwise strand sender-visible space, extends
> TCP_REPAIR_WINDOW so repair/restore can round-trip the new state, and adds
> truesize-drift coverage through TUN packetdrill tests and netdevsim-based
> selftests.

The series is IMHO significantly not trivial. Can the end-user meet the
relevant condition in practice? How? What is the net benefit in
practice? Is that observable under usual conditions or require
exceptional circumstances?

I think we need a strong motivation to merge this kind of changes.

/P