Re: [PATCH v2 5/5] mm/rmap: add anon folio unmap dispatcher

["David Hildenbrand (Arm)" <david@kernel.org>]

On 7/10/26 07:59, Dev Jain wrote:
> Add ttu_anon_folio() as the common entry point for anonymous folio
> unmapping. It dispatches to the lazyfree or swapbacked helper as
> appropriate.
> 
> Keep restoration of cleared PTEs in the caller, where the PTEs were
> removed.
> 
> No functional change intended.
> 
> Signed-off-by: Dev Jain <dev.jain@arm.com>
> ---
>  mm/rmap.c | 47 +++++++++++++++++++++++++----------------------
>  1 file changed, 25 insertions(+), 22 deletions(-)
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 68459f23f5c0a..55aa3ff8bf216 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -2172,6 +2172,28 @@ static bool ttu_anon_swapbacked_folio(struct vm_area_struct *vma,
>  	return true;
>  }
>  
> +static bool ttu_anon_folio(struct vm_area_struct *vma, struct folio *folio,
> +		struct page *page, unsigned long address, pte_t *ptep,
> +		pte_t pteval, unsigned long nr_pages)
> +{
> +	/*
> +	 * Store the swap location in the pte.
> +	 * See handle_pte_fault() ...
> +	 */
> +	if (unlikely(folio_test_swapbacked(folio) !=
> +			folio_test_swapcache(folio))) {
> +		WARN_ON_ONCE(1);

Can't you directly do

if (WARN_ON_ONCE(...))
	return false;

That even implies the unlikely() :)

> +		return false;
> +	}
> +
> +	if (!folio_test_swapbacked(folio))
> +		return ttu_anon_lazyfree_folio(vma, folio, nr_pages);
> +
> +	/* nr_pages > 1 not supported yet */
> +	return ttu_anon_swapbacked_folio(vma, folio, page, address, ptep,

LGTM

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David