lkml.org 
[lkml]   [2012]   [Jun]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] Add a page cache-backed balloon device driver.
On Tue, Jun 26, 2012 at 04:45:36PM -0700, Frank Swiderski wrote:
> On Tue, Jun 26, 2012 at 2:45 PM, Rik van Riel <riel@redhat.com> wrote:
> > On 06/26/2012 05:31 PM, Frank Swiderski wrote:
> >>
> >> On Tue, Jun 26, 2012 at 1:40 PM, Rik van Riel<riel@redhat.com>  wrote:
> >
> >
> >>> The code looks good to me, my only worry is the
> >>> code duplication. We now have 5 balloon drivers,
> >>> for 4 hypervisors, all implementing everything
> >>> from scratch...
> >>
> >>
> >> Do you have any recommendations on this?  I could (I think reasonably
> >> so) modify the existing virtio_balloon.c and have it change behavior
> >> based on a feature bit or other configuration.  I'm not sure that
> >> really addresses the root of what you're pointing out--it's still
> >> adding a different implementation, but doing so as an extension of an
> >> existing one.
> >
> >
> > Ideally, I believe we would have two balloon
> > top parts in a guest (one classical balloon,
> > one on the LRU), and four bottom parts (kvm,
> > xen, vmware & s390).
> >
> > That way the virt specific bits of a balloon
> > driver would be essentially a ->balloon_page
> > and ->release_page callback for pages, as well
> > as methods to communicate with the host.
> >
> > All the management of pages, including stuff
> > like putting them on the LRU, or isolating
> > them for migration, would be done with the
> > same common code, regardless of what virt
> > software we are running on.
> >
> > Of course, that is a substantial amount of
> > work and I feel it would be unreasonable to
> > block anyone's code on that kind of thing
> > (especially considering that your code is good),
> > but I do believe the explosion of balloon
> > code is a little worrying.
> >
>
> Hm, that makes a lot of sense. That would be a few patches definitely
> worth doing, IMHO. I'm not entirely sure how I feel about inflating
> the balloon drivers in the meantime. Sigh, and I didn't even mean
> that as a pun.
>
> fes

Actually I'm not 100% sure the num_pages interface
of the classical balloon is a good fit for the LRU
balloon. Let's figure that out first: if we fork the interface
there might not be all that much common code ...

--
MST
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2012-06-27 12:41    [W:0.044 / U:0.100 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site