Re: [PATCH 0/3] KVM-userspace: add NUMA support for guests

[Andi Kleen <andi@firstfloor.org>]

> I don't think the first one works without the second.  Calling getcpu() 
> on startup is meaningless since the initial placement doesn't take the 

Who said anything about startup? The idea behind getcpu() is to call
it every time you allocate someting.

> >
> >Anyways it's not ideal either, but in my mind would be all preferable
> >to default CPU pinning.
> 
> I agree we need something dynamic, and that we need to tie cpu affinity 
> and memory affinity together.
> 
> This could happen completely in the kernel (not an easy task), or by 

There were experimental patches for tieing memory migration to cpu migration 
some time ago from Lee S.

> having a second-level scheduler in userspace polling for cpu usage an 
> rebalancing processes across numa nodes.  Given that with virtualization 
> you have a few long lived processes, this does not seem too difficult.

I think I would prefer to fix that in the kernel. user space will never
have the full picture.

-Andi

-- 
ak@linux.intel.com