Re: [Xen-devel] Re: [PATCH] xen: core dom0 support

[Jody Belka <lists-xen@pimb.org>]

On Sat, Feb 28, 2009 at 11:09:07PM +1100, Nick Piggin wrote:
> On Saturday 28 February 2009 17:52:24 Jeremy Fitzhardinge wrote:
> > Andrew Morton wrote:
> 
> > > I hate to be the one to say it, but we should sit down and work out
> > > whether it is justifiable to merge any of this into Linux.  I think
> > > it's still the case that the Xen technology is the "old" way and that
> > > the world is moving off in the "new" direction, KVM?
> >
> > I don't think that's a particularly useful way to look at it.  They're
> > different approaches to the problem, and have different tradeoffs.
> >
> > The more important question is: are there real users for this stuff?
> > Does not merging it cause more net disadvantage than merging it?
> > Despite all the noise made about kvm in kernel circles, Xen has a large
> > and growing installed base.  At the moment its all running on massive
> > out-of-tree patches, which doesn't make anyone happy.  It's best that it
> > be in the mainline kernel.  You know, like we argue for everything else.
> 
> OTOH, there are good reasons not to duplicate functionality, and many
> many times throughout the kernel history competing solutions have been
> rejected even though the same arguments could be made about them.

Is it duplication though? I personally have machines with older processors
that don't have hvm support. I plan on keeping these around for a good amount
of time, and would love to be running them on mainline. So for me, unless KVM
is somehow going to support para-virtualisation, this isn't duplication.

Just my own personal viewpoint as a user of xen.