Re: [PATCH v9 08/15] hugetlb: Use the has_hwpoisoned flag

[Pedro Falcato <pfalcato@suse.de>]

On Wed, Aug 05, 2026 at 10:05:48PM +0100, Matthew Wilcox (Oracle) wrote:
> Other large folios use the has_hwpoisoned flag.  Convert hugetlb to match.
> This will help us use the per-page hwpoison flag in the future.
> 
> Also introduce a folio_test_huge_poison().  This has exactly the same
> meaning as folio_test_has_hwpoisoned() but can be used when we don't have
> a reference to the folio containing the page.  folio_test_has_hwpoisoned()
> can race with folio splitting / reallocation and trip the assertions
> in const_folio_flags().
> 
> This closes a gap where a page in a previously-poisoned hugetlb folio
> could be observed to not have the hwpoison bit set.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Reviewed-by: Jane Chu <jane.chu@oracle.com>
> Reviewed-by: Gregory Price (Meta) <gourry@gourry.net>
> ---  
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 9e0ca4824905..e666dd14ca0c 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -843,11 +843,15 @@ config PERSISTENT_HUGE_ZERO_FOLIO
>  config MM_ID
>  	def_bool n
>  
> +config LARGE_FOLIO
> +	def_bool n

random nit: def_bool n means the same as just bool

I can't comment on hwpoison stuff, sorry :)
-- 
Pedro