Re: [PATCH 1/8] THP: Use real address for NUMA policy

[Peter Zijlstra]

On Wed, Aug 28, 2013 at 11:18:14AM +0200, Ingo Molnar wrote:
> But ideally THP should detect cases where a hugepage is heavily used from 
> multiple nodes and un-HP the page in question. Or not turn it into a 
> hugepage in the first place. (We actually have a memory access pattern 
> sampling facility in place upstream, the new CONFIG_NUMA_BALANCING=y code, 
> which could in theory be utilized.)

Mel and I spoke about doing just that a few weeks ago. Breaking up THP
pages when we get shared faults from different nodes and avoiding
coalescing when the pages are from different nodes.

Rik seemed a little skeptical about the entire thing saying that the
huge tlb gain is about the same order as the locality thing -- while
this is more or less true for the 'tiny' machines most of us have, this
is clearly not the case for these big machines.
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