On Dec 31, 2013, at 11:31 AM, Tim Deegan <tim@xen.org> wrote:
> At 10:33 -0500 on 31 Dec (1388482410), Konrad Rzeszutek Wilk wrote:
>> On Mon, Dec 23, 2013 at 06:34:55PM +0000, Russell Pavlicek wrote:
>>> On Twitter, Florian Heigl sent a out a few messages about issues
with xenpaging:
>>>
>>> ---
>>> 19-Dec: Anyone successfully use
#xen<https://twitter.com/search?q=%23xen&src=hash>
#xenpaging<https://twitter.com/search?q=%23xenpaging&src=hash>? docs
are at SLES manual, rest is mostly this:
http://www.gossamer-threads.com/lists/xen/devel/255798<http://t.co/P36VdL84Et>
dead feature or usable?
>>>
>>> 22-Dec: @lars_kurth<https://twitter.com/lars_kurth>
@RCPavlicek<https://twitter.com/RCPavlicek> Hey guys, I wrote down as much
as I could https://piratenpad.de/p/Ik3lOBLniq1L5TEM
<https://t.co/e5LQCUD9d0> (since I'm on holiday and not constant
online)
>>>
>>> 22-Dec: Yay, tested
#xen<https://twitter.com/search?q=%23xen&src=hash> Xenpaging (memory
overcommit)
>>> [x] largely untested
>>> [x] docs outdated
>>> [x] syntax+logic changed
>>> [x] broken
>>> ---
>>>
>>> [I've taken the liberty of removing the colorful expletive from
the final post]
>>>
>>> Is Florian's assessment correct, or is there somewhere we can
point him for help? I'm on vacation this week, but if someone replies to
me, I will try to forward the information appropriately.
>>
>> The Maintainers file implies otherwise. Let me CC the maintainers.
>
> Andres really owns this code, so I'll punt to him for an official
> answer, but:
The part actively maintained is the hypervisor support for paging, and the
interface.
tools/xenpaging is one way to consume that interface. It seems to have suffered
from bitrot.
So other than echoing Tim's points below, I'll add
- Some interesting ideas thrown around by Florian in his notes. Could lead to a
robust discussion in xen-devel … if Florian is still interested.
- Perhaps the developers who are interested (myself included) should make a
decent effort at improving the in-tree tools. There is the argument that for
example KSM gives KVM users a sharing solution that just works, whether you like
the results or not. In that vein xenpaging apparently doesn't cut it, nor
the absence of a basic sharing tool.
One simple paging tool could be lazy restore. There is some interest out there,
it would be relatively straightforward to codify.
Andres>
> - It's been listed as a 'tech preview' on the feature list
since it went
> in. http://wiki.xenproject.org/wiki/Xen_Release_Features says:
> "Preview, due to limited tools support. Hypervisor side in good
shape."
>
> - I can't say anything about SuSE's apparent support for it, except
> that ISTR Olaf worked at/for/with SuSE at the time.
>
> - Patches would, of course, be welcome.
>
> Tim.