Re: [PATCH 4/8] mm/swap: Use PG_dropbehind instead of PG_reclaim

[David Hildenbrand <david@redhat.com>]

On 13.01.25 10:34, Kirill A. Shutemov wrote:
> The recently introduced PG_dropbehind allows for freeing folios
> immediately after writeback. Unlike PG_reclaim, it does not need vmscan
> to be involved to get the folio freed.
> 
> Instead of using folio_set_reclaim(), use folio_set_dropbehind() in
> lru_deactivate_file().
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
>   mm/swap.c | 8 +-------
>   1 file changed, 1 insertion(+), 7 deletions(-)
> 
> diff --git a/mm/swap.c b/mm/swap.c
> index fc8281ef4241..4eb33b4804a8 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -562,14 +562,8 @@ static void lru_deactivate_file(struct lruvec *lruvec, struct folio *folio)
>   	folio_clear_referenced(folio);
>   
>   	if (folio_test_writeback(folio) || folio_test_dirty(folio)) {
> -		/*
> -		 * Setting the reclaim flag could race with
> -		 * folio_end_writeback() and confuse readahead.  But the
> -		 * race window is _really_ small and  it's not a critical
> -		 * problem.
> -		 */
>   		lruvec_add_folio(lruvec, folio);
> -		folio_set_reclaim(folio);
> +		folio_set_dropbehind(folio);
>   	} else {
>   		/*
>   		 * The folio's writeback ended while it was in the batch.

Acked-by: David Hildenbrand <david@redhat.com>

-- 
Cheers,

David / dhildenb