Hello! Sorry, but i did not get any answer to the last question. Would it be OK to
require <memoryBacking> and implicitly add only
shared mode ?
Kind regards,
Pavel Fedin
Senior Engineer
Samsung Electronics Research center Russia
-----Original Message-----
From: libvir-list-bounces(a)redhat.com [mailto:libvir-list-bounces@redhat.com] On Behalf
Of
Pavel Fedin
Sent: Thursday, February 11, 2016 5:36 PM
To: 'Daniel P. Berrange'
Cc: 'Libvirt'
Subject: Re: [libvirt] [RFC] vhost-user + shared memory + NUMA
Hello!
> > Ok, then would it be a good compromise if we require <memoryBacking>,
and only
implicitly
> add "shared" if we have vhost-user
> > devices? This way we would not change the way the guest memory is allocated.
>
> Adding shared implicitly *will* change the way guest memory is allocated,
> as it will have to use tmpfs to make it shared.
You perhaps didn't get my idea. I meant - we will still need to specify
<memoryBacking> with
huge pages, just no <numa>. Therefore, the memory will be allocated via file
backend from
hugetlbfs. Only mode will be changed implicitly (private -> shared).
> > IMHO being able to manually specify "shared" both in <numa>
and
> > in <memoryBacking> would be ambiguous.
>
> That's not really any different to what we have already with NUMA.
> The top level setting would apply as the default, and the NUMA level
> settings override it if needed.
Well, the only little drawback would be necessity to add "shared" by itself.
This would
require additional patching to clients (e. g. openstack).
Kind regards,
Pavel Fedin
Senior Engineer
Samsung Electronics Research center Russia
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