Re: Strange memory balloning problem even if balloning is disabled

[David Vrabel <david.vrabel@citrix.com>]

On 03/03/15 09:05, Fabio Fantoni wrote:
> Il 02/03/2015 17:31, David Vrabel ha scritto:
>> On 02/03/15 16:23, Jan Beulich wrote:
>>>>>> On 02.03.15 at 16:52, <fabio.fantoni@m2r.biz> wrote:
>>>> On systems with wheezy as dom0 and kernel 3.2 it seems there are no 
>>>> visible problems.
>>>> After updating the kernel to 3.16 (from backports repository), after 
>>>> starting the domUs, I get many of these errors in syslog and kern.log 
>>>> (infinite loop):
>>>> xen:balloon: Cannot add additional memory (-17)
>>> I have a vague recollection of some fix from David aiming at
>>> avoiding to issue this message, but you would clearly have better
>>> luck getting a qualified response if you Cc-ed kernel people when
>>> reporting kernel problems (assuming you need explicit Cc-s at all,
>>> as most relevant people read the list anyway afaik) - I certainly
>>> can't figure by what criteria you put together the Cc list.
>> You need
>>
>> 3dcf63677d4eb7fdfc13290c8558c301d2588fe8 (xen/balloon: cancel ballooning
>> if adding new memory failed)
>> fd8b79511349efd1f0decea920f61b93acb34a75 (xen/balloon: Don't continue
>> ballooning when BP_ECANCELED is encountered)
>>
>> Or you can disable CONFIG_XEN_BALLOON_MEMORY_HOTPLUG.
>>
>> David
> 
> Readded the other part of my initial mail that explain better the
> problem (also with the patch above applied)...
> 
> The strange thing is that it should not use balloning because both dom0
> and domUs have fixed memory set and balloning disabled.

Ballooned pages are required to back grant mapped pages in blkback and
netback.

David