Re: [PATCH 0/3][RFC] NUMA: add host side pinning

[Andi Kleen <andi@firstfloor.org>]

Anthony Liguori <anthony@codemonkey.ws> writes:
>
> If we extended integrated -mem-path with -numa such that a different
> path could be used with each numa node (and we let an explicit file be
> specified instead of just a directory), then if I understand
> correctly, we could use numactl without any specific integration in
> qemu.  Does this sound correct?

It's a bit tricky to coordinate because numactl policy only helps
before first fault (unless you want to migrate, but that has more
overhead), and if you run the numactl in parallel with qemu
you never know who faults first. So you would need another step in
precreating the files before starting qemu.

Another issue with using tmpfs this way is that you first need to resize
it to be larger than 0.5*RAM.  So more configuration hazzle.

Overall it would be rather a lot of steps this way. I guess
most people would put it into a wrapper, but why not have
that wrapper in qemu directly? Supporting interleave too
would be rather straight forward.

Also a lot of things you could do with numactl on shm you 
can be also done after the fact with cpusets.

-Andi 

-- 
ak@linux.intel.com -- Speaking for myself only.