Re: [PATCH] mm/huge_memory: remove enforce_sysfs from __thp_vma_allowable_orders

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

On Thu, Aug 21, 2025 at 04:00:38PM +0100, Usama Arif wrote:
> Using forced_collapse directly is clearer and enforce_sysfs is not
> really needed.

NIT, but would prefer a little more detail here e.g.:

	mm/huge_memory: rename variable for clarity

	There's no need to define a new local variable in
	__thp_vma_allowable_orders(), it's simply clearer to use the
	existing forced_collapse value to determine whether to force a
	collapse.

>
> Signed-off-by: Usama Arif <usamaarif642@gmail.com>

LGTM, so:

Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

> ---
> This was agreed upon in [1]
> [1] https://lore.kernel.org/all/cd99f0f2-260d-4494-bbf6-99daec3e0683@gmail.com/
> ---
>  mm/huge_memory.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 6fd714bd04844..5220dbc9fcb31 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -105,7 +105,6 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
>  	const bool smaps = type == TVA_SMAPS;
>  	const bool in_pf = type == TVA_PAGEFAULT;
>  	const bool forced_collapse = type == TVA_FORCED_COLLAPSE;
> -	const bool enforce_sysfs = !forced_collapse;
>  	unsigned long supported_orders;
>
>  	/* Check the intersection of requested and supported orders. */
> @@ -168,14 +167,14 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
>  	if (!in_pf && shmem_file(vma->vm_file))
>  		return orders & shmem_allowable_huge_orders(file_inode(vma->vm_file),
>  						   vma, vma->vm_pgoff, 0,
> -						   !enforce_sysfs);
> +						   forced_collapse);
>
>  	if (!vma_is_anonymous(vma)) {
>  		/*
> -		 * Enforce sysfs THP requirements as necessary. Anonymous vmas
> +		 * Enforce THP collapse requirements as necessary. Anonymous vmas
>  		 * were already handled in thp_vma_allowable_orders().
>  		 */
> -		if (enforce_sysfs &&
> +		if (!forced_collapse &&
>  		    (!hugepage_global_enabled() || (!(vm_flags & VM_HUGEPAGE) &&
>  						    !hugepage_global_always())))
>  			return 0;
> --
> 2.47.3
>
>