> 3) As I have mentioned above, with this idea, netdev_alloc_skb() will > allocate > as usual, the data pointed by skb->data will be copied into the first > guest buffer. > That means we should reserve sufficient room in guest buffer. For PS > mode > supported driver (for example ixgbe), the room will be more than 128. > After 128bytes, > we will put the first frag data. Look into virtio-net.c the function > page_to_skb() > and receive_mergeable(), that means we should modify guest virtio-net > driver to > compute the offset as the parameter for skb_set_frag(). > > How do you think about this? Attached is a patch to how to modify the > guest driver. > I reserve 512 bytes as an example, and transfer the header len of the > skb in hdr->hdr_len. > Xiaohui & Herbert: Mixing copy of head & 0-copy of bulk data imposes additional challange to find the guest buffer. The backend driver may be unable to find a spare guest buffer from virtqueue at that time which may block the receiving process then. Can't we completely eliminate netdev_alloc_skb here? Assigning guest buffer at this time makes life much easier. Thx, Eddie -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
