Subject: Re: [PATCH v4 5/5] vsock/virtio: change the maximum packet size allowed

From: "Michael S. Tsirkin" <[email-masked]>
Date: Thu, 18 Jul 2019 08:33:40 -0400

On Thu, Jul 18, 2019 at 09:52:41AM +0200, Stefano Garzarella wrote:
> On Wed, Jul 17, 2019 at 5:00 PM Michael S. Tsirkin <[email-masked]> wrote:
> >
> > On Wed, Jul 17, 2019 at 01:30:30PM +0200, Stefano Garzarella wrote:
> > > Since now we are able to split packets, we can avoid limiting
> > > their sizes to VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE.
> > > Instead, we can use VIRTIO_VSOCK_MAX_PKT_BUF_SIZE as the max
> > > packet size.
> > >
> > > Signed-off-by: Stefano Garzarella <[email-masked]>
> >
> >
> > OK so this is kind of like GSO where we are passing
> > 64K packets to the vsock and then split at the
> > low level.
> 
> Exactly, something like that in the Host->Guest path, instead in the
> Guest->Host we use the entire 64K packet.
> 
> Thanks,
> Stefano

btw two allocations for each packet isn't great. How about
allocating the struct linearly with the data?
And all buffers are same length for you - so you can actually
do alloc_pages.
Allocating/freeing pages in a batch should also be considered.

-- 
MST