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

Nico Pache
2026-05-04T03:57:04Z

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);
> }
>