netdev - Re: [PATCH net v2] net: don't keep lonely packets forever in the gro hash

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Date:   Wed, 21 Nov 2018 12:33:22 -0500
From:   Willem de Bruijn <willemdebruijn.kernel@...il.com>
To:     Paolo Abeni <pabeni@...hat.com>
Cc:     Network Development <netdev@...r.kernel.org>,
        David Miller <davem@...emloft.net>,
        Eric Dumazet <eric.dumazet@...il.com>
Subject: Re: [PATCH net v2] net: don't keep lonely packets forever in the gro hash

On Wed, Nov 21, 2018 at 12:21 PM Paolo Abeni <pabeni@...hat.com> wrote:
>
> Eric noted that with UDP GRO and NAPI timeout, we could keep a single
> UDP packet inside the GRO hash forever, if the related NAPI instance
> calls napi_gro_complete() at an higher frequency than the NAPI timeout.
> Willem noted that even TCP packets could be trapped there, till the
> next retransmission.
> This patch tries to address the issue, flushing the old packets -
> those with a NAPI_GRO_CB age before the current jiffy - before scheduling
> the NAPI timeout. The rationale is that such a timeout should be
> well below a jiffy and we are not flushing packets eligible for sane GRO.
>
> v1  -> v2:
>  - clarified the commit message and comment
>
> RFC -> v1:
>  - added 'Fixes tags', cleaned-up the wording.
>
> Reported-by: Eric Dumazet <eric.dumazet@...il.com>
> Fixes: 3b47d30396ba ("net: gro: add a per device gro flush timer")
> Signed-off-by: Paolo Abeni <pabeni@...hat.com>

Acked-by: Willem de Bruijn <willemb@...gle.com>

Thanks for making those small changes.