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From:   Eric Dumazet <edumazet@google.com>
Date:   Tue, 6 Jun 2023 09:25:27 +0200
Message-ID: <CANn89iLA0Wo4nHKHWatGKAoRXktG64HWbkDACuoFGYw3KHPhew@mail.gmail.com>
Subject: Re: [PATCH v3 1/1] gro: decrease size of CB
To:     Richard Gobert <richardbgobert@gmail.com>
Cc:     davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
        aleksander.lobakin@intel.com, lixiaoyan@google.com,
        lucien.xin@gmail.com, alexanderduyck@fb.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
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On Thu, Jun 1, 2023 at 6:14=E2=80=AFPM Richard Gobert <richardbgobert@gmail=
.com> wrote:
>
> The GRO control block (NAPI_GRO_CB) is currently at its maximum size.
> This commit reduces its size by putting two groups of fields that are
> used only at different times into a union.
>
> Specifically, the fields frag0 and frag0_len are the fields that make up
> the frag0 optimisation mechanism, which is used during the initial
> parsing of the SKB.
>
> The fields last and age are used after the initial parsing, while the
> SKB is stored in the GRO list, waiting for other packets to arrive.
>
> There was one location in dev_gro_receive that modified the frag0 fields
> after setting last and age. I changed this accordingly without altering
> the code behaviour.
>
> Signed-off-by: Richard Gobert <richardbgobert@gmail.com>

Reviewed-by: Eric Dumazet <edumazet@google.com>