Re: [virtio-dev] Re: [PATCH v9 2/5] virtio-balloon: VIRTIO_BALLOON_F_BALLOON_CHUNKS

[Michael S. Tsirkin]

On Thu, Apr 27, 2017 at 02:31:49PM +0800, Wei Wang wrote:
> On 04/27/2017 07:20 AM, Michael S. Tsirkin wrote:
> > On Wed, Apr 26, 2017 at 11:03:34AM +0000, Wang, Wei W wrote:
> > > Hi Michael, could you please give some feedback?
> > I'm sorry, I'm not sure feedback on what you are requesting.
> Oh, just some trivial things (e.g. use a field in the
> header, hdr->chunks to indicate the number of chunks
> in the payload) that wasn't confirmed.
> 
> I will prepare the new version with fixing the agreed issues,
> and we can continue to discuss those parts if you still find
> them improper.
> 
> 
> > 
> > The interface looks reasonable now, even though there's
> > a way to make it even simpler if we can limit chunk size
> > to 2G (in fact 4G - 1). Do you think we can live with this
> > limitation?
> Yes, I think we can. So, is it good to change to use the
> previous 64-bit chunk format (52-bit base + 12-bit size)?

This isn't what I meant. virtio ring has descriptors with
a 64 bit address and 32 bit size.

If size < 4g is not a significant limitation, why not just
use that to pass address/size in a standard s/g list,
possibly using INDIRECT?

> 
> > 
> > But the code still needs some cleanup.
> > 
> 
> OK. We'll also still to discuss your comments in the patch 05.
> 
> Best,
> Wei