Re: [PATCH v3 2/2] mm/huge_memory: use folio_expected_ref_count() to calculate ref_count.

[Baolin Wang]

On 2025/7/15 01:18, Zi Yan wrote:
> Instead of open coding the ref_count calculation, use
> folio_expected_ref_count().
>
> Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
> Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
> Acked-by: Balbir Singh <balbirs@xxxxxxxxxx>
> Acked-by: David Hildenbrand <david@xxxxxxxxxx>
> ---

Looks more readable. Thanks.
Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>

>   mm/huge_memory.c | 12 +++++-------
>   1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index a7ee731f974f..31b5c4e61a57 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -3735,6 +3735,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
>   	if (folio_ref_freeze(folio, 1 + extra_pins)) {
>   		struct address_space *swap_cache = NULL;
>   		struct lruvec *lruvec;
> +		int expected_refs;
>   
>   		if (folio_order(folio) > 1 &&
>   		    !list_empty(&folio->_deferred_list)) {
> @@ -3805,11 +3806,8 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
>   		     new_folio = next) {
>   			next = folio_next(new_folio);
>   
> -			folio_ref_unfreeze(
> -				new_folio,
> -				1 + ((mapping || swap_cache) ?
> -					     folio_nr_pages(new_folio) :
> -					     0));
> +			expected_refs = folio_expected_ref_count(new_folio) + 1;
> +			folio_ref_unfreeze(new_folio, expected_refs);
>   
>   			lru_add_split_folio(folio, new_folio, lruvec, list);
>   
> @@ -3839,8 +3837,8 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
>   		 * Otherwise, a parallel folio_try_get() can grab origin_folio
>   		 * and its caller can see stale page cache entries.
>   		 */
> -		folio_ref_unfreeze(folio, 1 +
> -			((mapping || swap_cache) ? folio_nr_pages(folio) : 0));
> +		expected_refs = folio_expected_ref_count(folio) + 1;
> +		folio_ref_unfreeze(folio, expected_refs);
>   
>   		unlock_page_lruvec(lruvec);
>