Re: [PATCH v5 03/14] mm/huge_memory: remove READ_ONLY_THP_FOR_FS from file_thp_enabled()

[Nico Pache <npache@redhat.com>]

On 4/29/26 9:29 AM, Zi Yan wrote:
> Replace it with a check on the max folio order of the file's address space
> mapping, making sure PMD folio is supported. Keep the inode open-for-write
> check, since even if collapse_file() now makes sure all to-be-collapsed
> folios are clean and the created PMD file THP can be handled by FSes
> properly, the filemap_flush() could perform undesirable write back.
> 
> Signed-off-by: Zi Yan <ziy@nvidia.com>
> ---
>   mm/huge_memory.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 2f3fcb4dd1ef8..3b324f03e9283 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -86,9 +86,6 @@ static inline bool file_thp_enabled(struct vm_area_struct *vma)
>   {
>   	struct inode *inode;
>   
> -	if (!IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS))
> -		return false;
> -
>   	if (!vma->vm_file)
>   		return false;
>   
> @@ -97,6 +94,9 @@ static inline bool file_thp_enabled(struct vm_area_struct *vma)
>   	if (IS_ANON_FILE(inode))
>   		return false;
>   
> +	if (!mapping_pmd_folio_support(vma->vm_file->f_mapping))

Other than my question in the previous patch about >= PMD_ORDER vs == 
PMD_ORDER.

LGTM

Reviewed-by: Nico Pache <npache@redhat.com>

> +		return false;
> +
>   	return !inode_is_open_for_write(inode) && S_ISREG(inode->i_mode);
>   }
>