Re: [PATCH 3/3] mm: remove page_mapped()

[David Hildenbrand (Arm)]

On 4/27/26 15:21, Andrew Morton wrote:
> On Mon, 27 Apr 2026 13:43:16 +0200 "David Hildenbrand (Arm)" <david@xxxxxxxxxx> wrote:
> 
>> Let's replace the last user of page_mapped() by folio_mapped() so we
>> can get rid of page_mapped().
>>
>> Replace the remaining occurrences of page_mapped() in rmap documentation
>> by folio_mapped().
> 
> This broke Breno's "mm/memory-failure: add panic option for
> unrecoverable pages"
> (https://lore.kernel.org/20260424-ecc_panic-v5-2-a35f4b50425c@xxxxxxxxxx),
> which added a new page_mapped() call.  I made the below adjustment to
> Breno's patch:
> 
> --- a/mm/memory-failure.c~mm-memory-failure-add-panic-option-for-unrecoverable-pages-fix
> +++ a/mm/memory-failure.c
> @@ -1353,7 +1353,7 @@ static bool panic_on_unrecoverable_mf(un
>  		cpu_relax();
>  		return page_count(p) == 0 &&
>  		       !PageLRU(p) &&
> -		       !page_mapped(p) &&
> +		       !folio_mapped(page_folio(p)) &&
>  		       !page_folio(p)->mapping &&

If we have a folio, we should really lookup the folio once. Not 4 times.

Breno's patch likely needs some love. :)

-- 
Cheers,

David