On Mon, Jan 20, 2014 at 03:48:36PM +0100, Alexander Graf wrote:

On 15.01.2014, at 07:36, Liu ping fan [off-list ref] wrote:

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On Thu, Jan 9, 2014 at 8:08 PM, Alexander Graf [off-list ref] wrote:

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On 11.12.2013, at 09:47, Liu Ping Fan [off-list ref] wrote:

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This series is based on Aneesh's series  "[PATCH -V2 0/5] powerpc: mm: Numa faults support for ppc64"

For this series, I apply the same idea from the previous thread "[PATCH 0/3] optimize for powerpc _PAGE_NUMA"
(for which, I still try to get a machine to show nums)

But for this series, I think that I have a good justification -- the fact of heavy cost when switching context between guest and host,
which is  well known.

This cover letter isn't really telling me anything. Please put a proper description of what you're trying to achieve, why you're trying to achieve what you're trying and convince your readers that it's a good idea to do it the way you do it.

Sorry for the unclear message. After introducing the _PAGE_NUMA,
kvmppc_do_h_enter() can not fill up the hpte for guest. Instead, it
should rely on host's kvmppc_book3s_hv_page_fault() to call
do_numa_page() to do the numa fault check. This incurs the overhead
when exiting from rmode to vmode.  My idea is that in
kvmppc_do_h_enter(), we do a quick check, if the page is right placed,
there is no need to exit to vmode (i.e saving htab, slab switching)

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If my suppose is correct, will CCing kvm@vger.kernel.org from next version.

This translates to me as "This is an RFC"?

Yes, I am not quite sure about it. I have no bare-metal to verify it.
So I hope at least, from the theory, it is correct.

Paul, could you please give this some thought and maybe benchmark it?

OK, once I get Aneesh to tell me how I get to have ptes with
_PAGE_NUMA set in the first place. :)

Paul.