On Thu, Dec 13, 2018 at 11:11:48AM +0800, jiangyiwen wrote:
> On 2018/12/13 3:09, David Miller wrote:
> > From: jiangyiwen <jiangyiwen@xxxxxxxxxx>
> > Date: Wed, 12 Dec 2018 17:29:31 +0800
> >
> >> diff --git a/include/uapi/linux/virtio_vsock.h b/include/uapi/linux/virtio_vsock.h
> >> index 1d57ed3..2292f30 100644
> >> --- a/include/uapi/linux/virtio_vsock.h
> >> +++ b/include/uapi/linux/virtio_vsock.h
> >> @@ -63,6 +63,11 @@ struct virtio_vsock_hdr {
> >> __le32 fwd_cnt;
> >> } __attribute__((packed));
> >>
> >> +/* It add mergeable rx buffers feature */
> >> +struct virtio_vsock_mrg_rxbuf_hdr {
> >> + __le16 num_buffers; /* number of mergeable rx buffers */
> >> +} __attribute__((packed));
> >> +
> >
> > I know the rest of this file uses 'packed' but this attribute should
> > only be used if absolutely necessary as it incurs a
> > non-trivial performance penalty for some architectures.
> >
> > .
> >
>
> Hi David,
>
> I hope Host can fill fewer bytes into rx virtqueue, so
> I keep structure virtio_vsock_mrg_rxbuf_hdr one byte
> alignment.
>
> Thanks,
> Yiwen.
It doesn't work like this now though, does it?
Buffers are preallocated and they are always aligned.
So I do not see the point.
--
MST
