netdev - Re: [PATCH RFC net-next 00/11] udp gso

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Message-ID: <CAKgT0Uf0e_pQuUKctEA_x8=hLw2UdA0n_HF8=mu-xtu28odvsg@mail.gmail.com>
Date:   Fri, 20 Apr 2018 19:08:31 -0700
From:   Alexander Duyck <alexander.duyck@...il.com>
To:     Willem de Bruijn <willemdebruijn.kernel@...il.com>
Cc:     David Miller <davem@...emloft.net>,
        Sowmini Varadhan <sowmini.varadhan@...cle.com>,
        "Samudrala, Sridhar" <sridhar.samudrala@...el.com>,
        Netdev <netdev@...r.kernel.org>,
        Willem de Bruijn <willemb@...gle.com>
Subject: Re: [PATCH RFC net-next 00/11] udp gso

On Fri, Apr 20, 2018 at 2:58 PM, Willem de Bruijn
<willemdebruijn.kernel@...il.com> wrote:
>>>> Also any plans for HW offload support for this? I vaguely recall that
>>>> the igb and ixgbe parts had support for something like this in
>>>> hardware. I would have to double check to see what exactly is
>>>> supported.
>>>
>>> I hadn't given that much thought until the request yesterday to
>>> expose the NETIF_F_GSO_UDP_L4 flag through ethtool. By
>>> virtue of having only a single fixed segmentation length, it
>>> appears reasonably straightforward to offload.
>>
>> Actually I just got a chance to start on a review of things. Do we
>> need to have to use both GSO_UDP and and GSO_UDP_L4? It might be
>> better if we could split these up and specifically call out GSO_UDP as
>> UFO and GSO_UDP_L4 as being UDP segmentation.
>
> Thanks for taking a look, Alex.
>
> Agreed, I'll revise that. My initial thought was that both gso skbs need
> to take the same udp gso special case branches in places like act_csum
> and ovs. But on rereading that seems an unsafe approach, as some
> branches are fragmentation specific. I'll review them all and add
> separate SKB_GSO_UDP_L4 cases where needed, instead.

Sounds good. Keep me in the loop on these patches. I will see if we
can get support for ixgbe, ixgbevf, and igb to at least offload this
since it shouldn't be much of a lift to get that. Once we have that I
can also take a look and see if there would be much work needed to add
gso_partial support so we could deal with tunnel encapsulated UDP
segmentation offload support on those devices.

Thanks.

- Alex