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

From: Mel Gorman
Date: Mon May 17 2021 - 11:46:49 EST

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@xxxxxxxxx>

Acked-by: Mel Gorman <mgorman@xxxxxxx>

Mel Gorman