Re: Re: Re: [virtio-comment] [PATCH v2 01/11] transport-fabrics: introduce Virtio Over Fabrics overview

[zhenwei pi <pizhenwei@bytedance.com>]

On 5/4/23 18:05, Michael S. Tsirkin wrote:
> On Thu, May 04, 2023 at 05:46:46PM +0800, zhenwei pi wrote:
> > On 5/4/23 16:57, David Hildenbrand wrote:
> > > On 04.05.23 10:19, zhenwei pi wrote:
> > > > In the past years, virtio supports lots of device specifications by
> > > > PCI/MMIO/CCW. These devices work fine in the virtualization environment.
> > > >
> > > > Introduce Virtio Over Fabrics transport to support "network defined
> > > > peripheral devices". With this transport, Many Virtio based devices
> > > > transparently work over fabrics. Note that the balloon device may not
> > > > make sense. Shared memory regions won't work.
> > >
> > > Anything that involves memory (memory balloon, memory device, shared
> > > memory) is fully incompatible I would guess.
> >
> > Hi,
> >
> > Agree that memory device and shared memory is incompatible.
> >
> > But memory balloon device, I don't know if it's possible to use in future.
> > As far as I can imagine: a user process runs virtio-of target by listening
> > localhost, and memory balloon isolates same pages from kernel, the user
> > process maps these physical pages into virtual memory ...
>
> I don't see anything big that is wrong with balloon. device inflates
> balloon, this memory is stolen from guest. isn't this what user
> wanted? presumably there's a way for device to send this
> information to the hypervisor otherwise it seems kind of
> pointless.

Hi,

A user process has a chance to steal some pages from a kernel, these 
pages will not be used by kernel(no memory migration, no KSM, no kswap 
on these pages). As of the current situation, this maybe seem pointless ...

I don't disagree with David's point about memory balloon. ^_^

--
zhenwei pi