Re: [Qemu-ppc] [PATCH 0/5] Improve balloon handling of pagesizes other than 4kiB

[David Gibson]

On Mon, Mar 04, 2019 at 09:13:03PM -0500, Michael S. Tsirkin wrote:
> On Tue, Mar 05, 2019 at 11:53:32AM +1100, David Gibson wrote:
> > On Thu, Feb 28, 2019 at 08:39:21AM -0500, Michael S. Tsirkin wrote:
> > > On Thu, Feb 14, 2019 at 03:39:11PM +1100, David Gibson wrote:
> > > > I posted some RFCs for this back in December, but didn't wrap it up in
> > > > time for 3.1.  Posting again for inclusion in 4.0.
> > > > 
> > > > The virtio-balloon devices was never really thought out for cases
> > > > other than 4kiB pagesize on both guest and host.  It works in some
> > > > cases, but in others can be ineffectual or even cause guest memory
> > > > corruption.
> > > > 
> > > > This series makes a handful of preliminary cleanups, then makes a
> > > > change to safely, though not perfectly, handle cases with non 4kiB
> > > > pagesizes.
> > > 
> > > I'd like to see a version of this that does not depend on patch 1 which
> > > is not a cleanup nor a bugfix. Could you look into this please?
> > 
> > Ok... the original series is already applied to master, so I'm not
> > exactly sure what you want me to do here.  Should I try to come up
> > with a "logical revert" of the first patch?  Or do you intend to
> > revert the whole series, and I rewrite the series without the first
> > patch?
> 
> Whatever you prefer. Maybe the best idea is to add a flag
> that says whether to madvise or not. Default can be compatible.
> Hmm?

Ok, will do.

As I was looking at this I noticed a bug in the current code.
Extremely unlikely to hit in practice, but could result in guest
memory corruption if it does.  So, I'll fix that as well.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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