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Date: Sun, 14 Jul 2013 13:34:25 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH V4 01/10] NUMA: Support multiple CPU ranges
 on -numa option
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To: Eric Blake <eblake@redhat.com>
Cc: aliguori@us.ibm.com, Eduardo Habkost <ehabkost@redhat.com>, qemu-devel@nongnu.org, lcapitulino@redhat.com, bsd@redhat.com, y-goto@jp.fujitsu.com, afaerber@suse.de, Wanlong Gao <gaowanlong@cn.fujitsu.com>

Il 08/07/2013 21:02, Eric Blake ha scritto:
> On 07/05/2013 12:41 PM, Eduardo Habkost wrote:
>> On Thu, Jul 04, 2013 at 05:53:08PM +0800, Wanlong Gao wrote:
>>> From: Bandan Das <bsd@redhat.com>
>>>
>>> This allows us to use the "cpus" property multiple times
>>> to specify multiple cpu (ranges) to the -numa option :
>>>
>>> -numa node,cpus=1,cpus=2,cpus=4
>>> or
>>> -numa node,cpus=1-3,cpus=5
>>>
>>> Note that after this patch, the defalut suffix of "-numa node,mem=N"
>>> will no longer be "M". So we must add the suffix "M" like "-numa node,mem=NM"
>>> when assigning "N MB" of node memory size.
>>
>> Such an incompatible change is not acceptable, as it would break
>> existing configurations. libvirt doesn't specify any suffix and expects
>> it to always mean "MB".
> 
> Newer libvirt can be taught to append 'M' when it detects it is talking
> to newer qemu.  While you have a point that it is annoying to force
> users to upgrade to a newer libvirt merely because they upgraded qemu,
> the libvirt point of view is that the following are supported:
> 
> old libvirt -> old qemu
> new libvirt -> old qemu
> new libvirt -> new qemu
> 
> but that this combination is always best effort and not required to work:
> 
> old libvirt -> new qemu

I don't think this is the case, unless you're talking of *very* old
libvirt (e.g. pre-QMP).

Paolo