Re: [RFC PATCH 0/9] virtio_net: support multi buffer xdp

Jason Wang
2022-12-02T05:42:54Z

On Fri, Dec 2, 2022 at 12:50 PM Heng Qi <hengqi@linux.alibaba.com> wrote:
>
> Hi, Jason.
>
> Do you have any comments on this series?

-EBUSY this week, but I will review it next week for sure.

Thanks

>
> Thanks.
>
> 在 2022/11/22 下午3:43, Heng Qi 写道:
> > Currently, virtio net only supports xdp for single-buffer packets
> > or linearized multi-buffer packets. This patchset supports xdp for
> > multi-buffer packets, then GRO_HW related features can be
> > negotiated, and do not affect the processing of single-buffer xdp.
> >
> > In order to build multi-buffer xdp neatly, we integrated the code
> > into virtnet_build_xdp_buff() for xdp. The first buffer is used
> > for prepared xdp buff, and the rest of the buffers are added to
> > its skb_shared_info structure. This structure can also be
> > conveniently converted during XDP_PASS to get the corresponding skb.
> >
> > Since virtio net uses comp pages, and bpf_xdp_frags_increase_tail()
> > is based on the assumption of the page pool,
> > (rxq->frag_size - skb_frag_size(frag) - skb_frag_off(frag))
> > is negative in most cases. So we didn't set xdp_rxq->frag_size in
> > virtnet_open() to disable the tail increase.
> >
> > Heng Qi (9):
> > virtio_net: disable the hole mechanism for xdp
> > virtio_net: set up xdp for multi buffer packets
> > virtio_net: update bytes calculation for xdp_frame
> > virtio_net: remove xdp related info from page_to_skb()
> > virtio_net: build xdp_buff with multi buffers
> > virtio_net: construct multi-buffer xdp in mergeable
> > virtio_net: build skb from multi-buffer xdp
> > virtio_net: transmit the multi-buffer xdp
> > virtio_net: support multi-buffer xdp
> >
> > drivers/net/virtio_net.c | 356 ++++++++++++++++++++++++---------------
> > 1 file changed, 219 insertions(+), 137 deletions(-)
> >
>