Re: [PATCH net-next v2 13/14] virtio_net: small: optimize code

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tue, Apr 18, 2023 at 2:53 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> Avoid the problem that some variables(headroom and so on) will repeat
> the calculation when process xdp.

While at it, if we agree to use separate code paths for building skbs.

It would be better to have a helper for building skb for non XDP
cases, then we can hide those calculation there.

Thanks

>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
>  drivers/net/virtio_net.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index f6f5903face2..5a5636178bd3 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -1040,11 +1040,10 @@ static struct sk_buff *receive_small(struct net_device *dev,
>         struct sk_buff *skb;
>         struct bpf_prog *xdp_prog;
>         unsigned int xdp_headroom = (unsigned long)ctx;
> -       unsigned int header_offset = VIRTNET_RX_PAD + xdp_headroom;
> -       unsigned int headroom = vi->hdr_len + header_offset;
> -       unsigned int buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
> -                             SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
>         struct page *page = virt_to_head_page(buf);
> +       unsigned int header_offset;
> +       unsigned int headroom;
> +       unsigned int buflen;
>
>         len -= vi->hdr_len;
>         stats->bytes += len;
> @@ -1072,6 +1071,11 @@ static struct sk_buff *receive_small(struct net_device *dev,
>         rcu_read_unlock();
>
>  skip_xdp:
> +       header_offset = VIRTNET_RX_PAD + xdp_headroom;
> +       headroom = vi->hdr_len + header_offset;
> +       buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
> +               SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
> +
>         skb = build_skb(buf, buflen);
>         if (!skb)
>                 goto err;
> --
> 2.32.0.3.g01195cf9f
>

_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization




[Index of Archives]     [KVM Development]     [Libvirt Development]     [Libvirt Users]     [CentOS Virtualization]     [Netdev]     [Ethernet Bridging]     [Linux Wireless]     [Kernel Newbies]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]

  Powered by Linux