Re: [PATCHv3, RESEND 6/8] khugepaged: Allow to collapse PTE-mapped compound pages

[Andrew Morton]

On Mon, 13 Apr 2020 15:52:18 +0300 "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> wrote:

> We can collapse PTE-mapped compound pages. We only need to avoid
> handling them more than once: lock/unlock page only once if it's present
> in the PMD range multiple times as it handled on compound level. The
> same goes for LRU isolation and putback.
> 
> ...
>
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -515,17 +515,30 @@ void __khugepaged_exit(struct mm_struct *mm)
>  
>  static void release_pte_page(struct page *page)
>  {
> -	dec_node_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page));

I have

	dec_node_page_state(page, NR_ISOLATED_ANON + page_is_file_lru(page));

here.  Is there some prerequisite which I wasn't able to find?