Re: [libvirt] [PATCH] add flag to enforce hugepage backing of guest RAM
On Tue, Feb 04, 2014 at 03:04:11PM -0700, Eric Blake wrote:
On 02/04/2014 02:57 PM, Marcelo Tosatti wrote:
>
>> So perhaps we do need some "policy" attribute on the
<hugepages/>
>> element to indicate desired behaviour here.
>
> What about the following new element under <hugepages/> ?
>
> enforce_hugepage_size=integer
Which feels a bit redundant (we're already under the <hugepages>
element, after all). Maybe:
<hugepages>
<size strict='yes' unit='G'>1</size>
</hugepages>
where strict could be no if we are giving a hint but don't care if the
hint cannot be honored (default yes if omitted), and where unit + value
Its awkward because you'd always want the largest hugepages size
possible, to reduce TLB pressure. So its hard to find use for
<size strict='no' unit='G'>1</size>
So what about <size strict unit='K/G/M'>x</size> ?
allows the user to input the size in a sensible unit (on output,
we'd
probably want to use unit='k' and spell out 1048576, for similarity with
all our other memory interfaces that output in k for back-compat reasons).
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org