Re: [PATCH 06/19] mm: numa: teach gup_fast about pmd_numa

[Ingo Molnar]

* Mel Gorman <mgorman@xxxxxxx> wrote:

> From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
> 
> When scanning pmds, the pmd may be of numa type (_PAGE_PRESENT not set),
> however the pte might be present. Therefore, gup_pmd_range() must return
> 0 in this case to avoid losing a NUMA hinting page fault during gup_fast.
> 
> Note: gup_fast will skip over non present ptes (like numa 
> types), so no explicit check is needed for the pte_numa case. 
> [...]

So, why not fix all architectures that choose to expose 
pte_numa() and pmd_numa() methods - via the patch below?

Thanks,

	Ingo

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