On Jan 3, 2014, at 1:41 PM, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
wrote:
> On Fri, Jan 03, 2014 at 09:49:36AM -0500, Andres Lagar-Cavilla wrote:
>>
>> 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 [x] docs outdated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.
>
> What is the other interface? Thanks!
Not sure what the question is. There is one interface. What I was referring to,
is that tools/xenpaging implements one specific paging policy: victim selection,
rate limiting, paging target, all of these are algorithms that entirely define
what bang for your money you will get.
Andres>>
>> 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.
>>