Re: [PATCH v1 05/18] mm: improve folio_likely_mapped_shared() using the mapcount of large folios

Yin, Fengwei
2024-04-19T14:03:50Z

On 4/10/2024 3:22 AM, David Hildenbrand wrote:
> We can now read the mapcount of large folios very efficiently. Use it to
> improve our handling of partially-mappable folios, falling back
> to making a guess only in case the folio is not "obviously mapped shared".
>
> We can now better detect partially-mappable folios where the first page is
> not mapped as "mapped shared", reducing "false negatives"; but false
> negatives are still possible.
>
> While at it, fixup a wrong comment (false positive vs. false negative)
> for KSM folios.
>
> Signed-off-by: David Hildenbrand <david@redhat.com>

Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>