Re: [Xen-devel] [RFC v2][PATCH 1/3] docs: design and intended usage for NUMA-aware ballooning

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 16.08.13 at 16:17, Li Yechen <lccycc123@xxxxxxxxx> wrote:
> On Fri, Aug 16, 2013 at 9:21 PM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>> As said - I'd want you to evaluate a model without such a new node,
>> and with instead the requirement placed on the balloon driver to
>> balloon out pages evenly allocated across the guest's virtual nodes.
> 
> Oh, so you need the experiments' result without this patch?
> I see. I'll do it and send the result.

What experiment?

>> You are exactly right again, this design is only for Linux balloon driver.
>> > For Linux, balloon can choose which page to balloon in/out. So we can
>> > assocate the pages with v-nodeid.
>> > For the other kinds of architechure, please forgive me that I haven't
>> think
>> > of that far...
>>
>> The abstract model shouldn't take OS implementation details or
>> policies into account; the implementation later of course can (and
>> frequently will need to).
>>
> So, you mean that the abstract model should consider that OS could not
> allocate pages by virtual node IDs?

No. What I said is that associating ballooned out pages with a
particular vNID seems wrong. If the balloon driver gets back a
fresh page during re-population, it shouldn't depend on having
a suitable vacated page control structure available, but instead
should be able to absorb the page in any case. But again, this
all is taking Linux concepts into consideration, which don't belong
in the architectural model (or at most as an example, but your
examples started _after_ you already started dealing with Linux
specifics).

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel