Re: [Qemu-devel] [virtio-dev] Re: [virtio-dev] Re: [virtio-dev] Re: [PATCH v1] virtio-net: enable configurable tx queue size

[Jason Wang]

On 2017年06月16日 11:22, Michael S. Tsirkin wrote:
> > I think the issues can be solved by VIRTIO_F_MAX_CHAIN_SIZE.
> >
> > For now, how about splitting it into two series of patches:
> > 1) enable 1024 tx queue size for vhost-user, to let the users of vhost-user
> > to easily use 1024 queue size.
> Fine with me. 1) will get property from user but override it on
> !vhost-user. Do we need a protocol flag? It seems prudent but we get
> back to cross-version migration issues that a04re still pending solution.
> Marc Andre, what's the status of that work?
>
> > 2) enable VIRTIO_F_MAX_CHAIN_SIZE,  to enhance robustness.
> Rather, to support it for more backends.

Ok, if we want to support different values of max chain size in the 
future. It would be problematic for migration of cross backends, 
consider the case when migrating from 2048 (vhost-user) to 1024 
(qemu/vhost-kernel).

Thanks

> > Best,
> > Wei
> --