Re: balloon manipulation within a domU?

["Cherry G. Mathew" <cherry.g.mathew%gmail.com@localhost>]

On 15 August 2012 11:49, Roger Pau Monne <roger.pau%citrix.com@localhost> wrote:
> Cherry G. Mathew wrote:
>> On 2 August 2012 07:51, Aaron J. Grier <agrier%poofygoof.com@localhost> 
>> wrote:
>>> On Wed, Aug 01, 2012 at 10:57:43AM +0100, Cherry G. Mathew wrote:
>>>>> the problem seems to be that the domU cannot write its own memory /
>>>>> target entry.
>>>> What is your dom0 setup ? xen kernel/tools version ? Does this hit you
>>>> from within a Linux domU ?
>>> I'm running NetBSD 6.0_BETA2 as Dom0:
>>> host                   : pythagoras.poofy.goof.com
>>> release                : 6.0_BETA2
>>> version                : NetBSD 6.0_BETA2 (XEN3_DOM0) #2: Mon Jun 11 
>>> 16:27:07 PDT 2012 
>>> agrier%pythagoras.poofy.goof.com@localhost:/disk/teraraid/obj/amd64/disk/teraraid/NetBSD/6/src/sys/arch/amd64/compile/XEN3_DOM0
>>>
>>> xenkernel41-4.1.2 and xentools41-4.1.2nb5 are compiled from pkgsrc.
>>>
>>> I haven't tried a Linux domU, but I think I have some OpenSUSE isos I
>>> could try.
>>
>> If the problem still persists, would be nice if you could file a PR so
>> this doesn't slip through the cracks
>
> I don't think Xen allows DomUs to change it's memory target, you can
> only modify the memory target from the Dom0, because the xenstore
> entries are protected (r/w from Dom0, r from DomU).
>
> /local/domain/9/memory/target = "1048577"   (n0,r9)

Hi Roger,

Can you point to the code for this please ? I'm able to write to the
target entry from Xen3 so I'm guessing this is a new constraint. If
this is the case, we'll have to modify the way balloon_thread() is
signalled.

Cheers,

-- 
~Cherry