Re: AF_XDP. Was: [net-next 00/12][pull request] Intel Wired LAN Driver Updates 2018-06-04

[Alexander Duyck <alexander.duyck@gmail.com>]

On Mon, Jun 4, 2018 at 4:32 PM, Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
> On Mon, Jun 04, 2018 at 03:02:31PM -0700, Alexander Duyck wrote:
>> On Mon, Jun 4, 2018 at 2:27 PM, David Miller <davem@davemloft.net> wrote:
>> > From: Or Gerlitz <gerlitz.or@gmail.com>
>> > Date: Tue, 5 Jun 2018 00:11:35 +0300
>> >
>> >> Just to make sure, is the AF_XDP ZC (Zero Copy) UAPI going to be
>> >> merged for this window -- AFAIU from [1], it's still under
>> >> examination/development/research for non Intel HWs, am I correct or
>> >> this is going to get in now?
>> >
>> > All of the pending AF_XDP changes will be merged this merge window.
>> >
>> > I think Intel folks need to review things as fast as possible because
>> > I pretty much refuse to revert the series or disable it in Kconfig at
>> > this point.
>> >
>> > Thank you.
>>
>> My understanding of things is that the current AF_XDP patches were
>> going to be updated to have more of a model agnostic API such that
>> they would work for either the "typewriter" mode or the descriptor
>> ring based approach. The current plan was to have the zero copy
>> patches be a follow-on after the vendor agnostic API bits in the
>> descriptors and such had been sorted out. I believe you guys have the
>> descriptor fixes already right?
>>
>> In my opinion the i40e code isn't mature enough yet to really go into
>> anything other than maybe net-next in a couple weeks. We are going to
>> need a while to get adequate testing in order to flush out all the
>> bugs and performance regressions we are likely to see coming out of
>> this change.
>
> I think the work everyone did in this release cycle increased my confidence
> that the way descriptors are defined and the rest of uapi are stable enough
> and i40e zero copy bits can land in the next release without uapi changes.
> In that sense even if we merge i40e parts now, the other nic vendors
> will be in the same situation and may find things that they would like
> to improve in uapi.
> So I propose we merge the first 7 patches of the last series now and
> let 3 remaining i40e patches go via intel trees for the next release.
> In the mean time other NIC vendors should start actively working
> on AF_XDP support as well.
> If somehow uapi would need tweaks, we can still do minor adjustments
> since 4.18 won't be released for ~10 weeks.
>

That works for me. Actually I think patch 11 can probably be included
as well since that is just sample code and could probably be used by
whatever drivers end up implementing this.

Thanks.

- Alex