Re: [PATCH 5/5] mm: support choosing to do THP COW for anonymous pmd entry.

[David Hildenbrand (Arm)]

> -	/*
> -	 * See do_wp_page(): we can only reuse the folio exclusively if
> -	 * there are no additional references. Note that we always drain
> -	 * the LRU cache immediately after adding a THP.
> -	 */
> -	if (folio_ref_count(folio) >
> -			1 + folio_test_swapcache(folio) * folio_nr_pages(folio))
> -		goto unlock_fallback;
>  	if (folio_test_swapcache(folio))

I don't see why you would want to remove this check, really. Instead of
"fallback", you might want to try copying the PMD.

-- 
Cheers,

David