Linux Virtualization - Mar 2023 - [PATCH net-next 2/8] virtio_net: mergeable xdp: introduce mergeable_xdp_prepare

On Thu, 23 Mar 2023 15:24:38 +0800, Yunsheng Lin <linyunsheng at
huawei.com> wrote:
> On 2023/3/23 13:40, Jason Wang wrote:
> >>>
> >>>>
> >>>> Also, it seems better to split the xdp_linearize_page() to
two functions
> >>>> as pskb_expand_head() and __skb_linearize() do, one to
expand the headroom,
> >>>> the other one to do the linearizing.
> >>>
> >>> No skb here.
> >>
> >> I means following the semantics of pskb_expand_head() and
__skb_linearize(),
> >> not to combine the headroom expanding and linearizing into one
function as
> >> xdp_linearize_page() does now if we want a better refoctor result.
> >
> > Not sure it's worth it, since the use is very specific unless we
could
> > find a case that wants only one of them.
>
> It seems receive_small() only need the headroom expanding one.
> For receive_mergeable(), it seems we can split into the below cases:
> 1. " (!xdp_prog->aux->xdp_has_frags && (num_buf > 1
|| headroom < virtnet_get_headroom(vi)))"
>    case only need linearizing.
> 2. other cases only need headroom/tailroom expanding.
>
> Anyway, it is your call to decide if you want to take this
> opportunity do a better refoctoring to virtio_net.
Compared to the chaotic state of the virtio-net XDP, this is a small point.
And I don?t think this brings any practical optimization. If you think this
division is better. You can submit a new patch on the top of this patch set.
I think the code can be clearer.

Thanks.
>
> >
> > Thanks
> >
> >>
> >>>
> >>>
> >>>>
> >>
> >
> >
> > .
> >