RE: [PATCH v3 1/1] Create debugfs file with hyper-v balloon usage information

[Michael Kelley (LINUX)]

From: Wei Liu <wei.liu@xxxxxxxxxx> Sent: Wednesday, July 13, 2022 8:19 AM
> 
> On Tue, Jul 12, 2022 at 04:24:12PM +0000, Michael Kelley (LINUX) wrote:
> > From: Alexander Atanasov <alexander.atanasov@xxxxxxxxxxxxx> Sent: Monday, July
> 11, 2022 11:18 AM
> > >
> > > Allow the guest to know how much it is ballooned by the host.
> > > It is useful when debugging out of memory conditions.
> > >
> > > When host gets back memory from the guest it is accounted
> > > as used memory in the guest but the guest have no way to know
> > > how much it is actually ballooned.
> > >
> > > Expose current state, flags and max possible memory to the guest.
> > > While at it - fix a 10+ years old typo.
> > >
> > > Signed-off-by: Alexander Atanasov <alexander.atanasov@xxxxxxxxxxxxx>
> > > ---
> [...]
> >
> > Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
> 
> I added "Drivers: hv:" prefix to the subject line and applied it to
> hyperv-next. Thanks.

Alexander -- I finally caught up on the long discussion of balloon
driver reporting that occurred over much of August.  I think your
original plan had been for each of the balloon driver to report
useful information in debugfs.  But as a result of the discussion,
it looks like virtio-balloon will be putting the information in
/proc/meminfo.  If that's the case, it seems like we should
drop these changes to the Hyper-V balloon driver,  and have
the Hyper-V balloon driver take the same approach as
virtio-balloon.

These Hyper-V balloon driver changes have already gone
into 6.0-rc1.  If we're going to drop them, we should do
the revert before 6.0 is done.

Thoughts?

Michael