Re: [PATCH 2/3] mm: huge_memory: add thp_vma_disabled()

[David Hildenbrand <david@redhat.com>]

On 10.10.24 08:10, Kefeng Wang wrote:
> Add thp_vma_disabled() helper to shared by shmem_allowable_huge_orders()
> and __thp_vma_allowable_orders().
> 
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
>   include/linux/huge_mm.h | 19 +++++++++++++++++++
>   mm/huge_memory.c        | 13 +------------
>   mm/shmem.c              |  7 +------
>   3 files changed, 21 insertions(+), 18 deletions(-)
> 
> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> index 795df660efa5..d77891332b35 100644
> --- a/include/linux/huge_mm.h
> +++ b/include/linux/huge_mm.h
> @@ -309,6 +309,25 @@ struct thpsize {
>   	(transparent_hugepage_flags &					\
>   	 (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG))
>   
> +static inline bool thp_vma_disabled(struct vm_area_struct *vma,
> +				    unsigned long vm_flags)
> +{
> +	/*
> +	 * Explicitly disabled through madvise or prctl, or some
> +	 * architectures may disable THP for some mappings, for
> +	 * example, s390 kvm.
> +	 */
> +	if (vma && ((vm_flags & VM_NOHUGEPAGE) ||
> +	     test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)))
> +		return true;
> +
> +	/* If the hardware/firmware marked hugepage support disabled. */
> +	if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED))
> +		return true;
> +
> +	return false;
> +}
> +

Should we call this "vma_thp_disabled()" ?

Also, I wonder if it would be more natural to check for the opposite ... 
  "vma_thp_enabled()", like we test for "allowed" and "suitable".

-- 
Cheers,

David / dhildenb