Re: [libvirt] [PATCH 1/3] add percentage limit parse and define support for RAM filesystems
On 12/05/2013 06:17 AM, Daniel P. Berrange wrote:
On Thu, Dec 05, 2013 at 06:12:22AM -0700, Eric Blake wrote:
> On 12/05/2013 04:56 AM, Daniel P. Berrange wrote:
>
>>>>>>
>>>>>> This patch enables percentage limit for ram filesystem
>>>>>>
>>>>>> <filesystem type='ram'>
>>>>>> <source usage='10%'/>
>>>>>> <target dir='/mnt'/>
>>>>>> </filesystem>
>>>>>>
>
We do have APIs for querying host RAM, but if we wanted this, which I
don't think we do, then tmpfs RAM % would want to be relative to guest
RAM allocation not host RAM.
Ah - if you make that argument, then I agree - a management tool can
always calculate a percentage of guest-visible RAM.
It doesn't make sense to have guest XML
whose semantics differ according to the host environment - they should
be self-contained.
Right - if we ever supported live migration, changing guest-visible
attributes during the migration is a non-starter. So the XML must not
be tied to host percentage, at which point I don't see a reason for
supporting percentage in the XML.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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