Re: [v2 PATCH 7/7] mm: thp: skip make PMD PROT_NONE if THP migration is not supported

Mel Gorman
2021-05-17T15:32:48Z

On Tue, Apr 13, 2021 at 02:24:16PM -0700, Yang Shi wrote:
> A quick grep shows x86_64, PowerPC (book3s), ARM64 and S390 support both
> NUMA balancing and THP. But S390 doesn't support THP migration so NUMA
> balancing actually can't migrate any misplaced pages.
>
> Skip make PMD PROT_NONE for such case otherwise CPU cycles may be wasted
> by pointless NUMA hinting faults on S390.
>
> Signed-off-by: Yang Shi <shy828301@gmail.com>

Acked-by: Mel Gorman <mgorman@suse.de>

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Mel Gorman
SUSE Labs