Re: [Hackathon minutes] PV frontends/backends and NUMA machines

[George Dunlap <george.dunlap@eu.citrix.com>]

On 05/21/2013 11:24 AM, Tim Deegan wrote:
> At 10:45 +0100 on 21 May (1369133137), George Dunlap wrote:
>> What we would want for a comparable domU -- a domU that was NUMA-aware
>> -- was to have the pfn layout in batches across the nodes to which it
>> will be pinned.  E.g., if a domU has its NUMA affinity set to nodes 2-3,
>> then you'd want the first half of the pfns to come from node 2, the
>> second half from node 3.
>>
>> In both cases, the domain builder will need to call the allocator with
>> specific numa nodes for specific regions of the PFN space.
>
> Ah, so that logic lives in the tools for domU?  I was misremembering.
> Anyway, I think I'm convinced that this is a reasonable thing to do
> the dom0 building code. :)

I don't think it lives anywhere at the moment -- I think at the moment 
the domain builder for both dom0 and domU just call the allocator 
without any directions, and the allocator reads the NUMA affinity mask 
for the domain.  But yes, when we do get guest NUMA support, I think the 
domain builder will be the right place to set up the guest NUMA layout, 
both for domUs and dom0.

Matt Wilson I think has some patches to do the domU layout for HVM 
guests -- if he could post those at some point in the next month, it 
might give a head start to the person implementing this (probably me at 
this point).

  -George