Re: [PATCH 7.2 v4 04/12] mm/khugepaged: remove READ_ONLY_THP_FOR_FS check in hugepage_enabled()

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

On 4/24/26 04:49, Zi Yan wrote:
> Remove READ_ONLY_THP_FOR_FS and khugepaged for file-backed pmd-sized
> hugepages are enabled by the global transparent hugepage control.
> khugepaged can still be enabled by per-size control for anon and shmem when
> the global control is off.
> 
> Add shmem_hpage_pmd_enabled() stub for !CONFIG_SHMEM to remove
> IS_ENABLED(SHMEM) in hugepage_enabled().
> 
> Clean up hugepage_enabled() by moving anon code to anon_hpage_enabled().
> 
> Signed-off-by: Zi Yan <ziy@nvidia.com>
> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> ---
>  include/linux/shmem_fs.h |  2 +-
>  mm/khugepaged.c          | 26 ++++++++++++++++----------
>  2 files changed, 17 insertions(+), 11 deletions(-)
> 
> diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
> index 93a0ba872ebe..acb8dd961b45 100644
> --- a/include/linux/shmem_fs.h
> +++ b/include/linux/shmem_fs.h
> @@ -127,7 +127,7 @@ int shmem_writeout(struct folio *folio, struct swap_iocb **plug,
>  void shmem_truncate_range(struct inode *inode, loff_t start, uoff_t end);
>  int shmem_unuse(unsigned int type);
>  
> -#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && defined(CONFIG_SHMEM)
>  unsigned long shmem_allowable_huge_orders(struct inode *inode,
>  				struct vm_area_struct *vma, pgoff_t index,
>  				loff_t write_end, bool shmem_huge_force);
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index 726f8ace01af..cdd4b37e4a68 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -524,26 +524,32 @@ static inline int collapse_test_exit_or_disable(struct mm_struct *mm)
>  		mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm);
>  }
>  
> +static inline bool anon_hpage_enabled(void)
> +{
> +	if (READ_ONCE(huge_anon_orders_always))
> +		return true;
> +	if (READ_ONCE(huge_anon_orders_madvise))
> +		return true;
> +	if (READ_ONCE(huge_anon_orders_inherit) &&
> +	    hugepage_global_enabled())
> +		return true;
> +	return false;
> +}

Ah, that is based on Nicos work, right?

> +
>  static bool hugepage_enabled(void)
>  {
>  	/*
>  	 * We cover the anon, shmem and the file-backed case here; file-backed
> -	 * hugepages, when configured in, are determined by the global control.
> +	 * hugepages are determined by the global control.
>  	 * Anon hugepages are determined by its per-size mTHP control.
>  	 * Shmem pmd-sized hugepages are also determined by its pmd-size control,
>  	 * except when the global shmem_huge is set to SHMEM_HUGE_DENY.
>  	 */
> -	if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) &&
> -	    hugepage_global_enabled())
> -		return true;
> -	if (READ_ONCE(huge_anon_orders_always))
> +	if (hugepage_global_enabled())
>  		return true;
> -	if (READ_ONCE(huge_anon_orders_madvise))
> -		return true;
> -	if (READ_ONCE(huge_anon_orders_inherit) &&
> -	    hugepage_global_enabled())
> +	if (anon_hpage_enabled())
>  		return true;
> -	if (IS_ENABLED(CONFIG_SHMEM) && shmem_hpage_pmd_enabled())
> +	if (shmem_hpage_pmd_enabled())
>  		return true;
>  	return false;
>  }

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

-- 
Cheers,

David