Re: [PATCH v10 14/37] mm: remove arch vma_alloc_zeroed_movable_folio overrides

[Lorenzo Stoakes <ljs@kernel.org>]

On Mon, Jun 08, 2026 at 04:37:08AM -0400, Michael S. Tsirkin wrote:
> Now that the generic vma_alloc_zeroed_movable_folio() uses
> __GFP_ZERO, the arch-specific macros on alpha, m68k, s390, and
> x86 that did the same thing are redundant.  Remove them.
>
> arm64 is not affected: it has a real function override that
> handles MTE tag zeroing, not just __GFP_ZERO.
>
> Suggested-by: David Hildenbrand <david@kernel.org>
> Acked-by: Magnus Lindholm <linmag7@gmail.com>
> Acked-by: Greg Ungerer <gerg@linux-m68k.org>
> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> Assisted-by: Claude:claude-opus-4-6
> Reviewed-by: Gregory Price <gourry@gourry.net>
> ---
>  arch/alpha/include/asm/page.h   | 3 ---
>  arch/m68k/include/asm/page_no.h | 3 ---
>  arch/s390/include/asm/page.h    | 3 ---
>  arch/x86/include/asm/page.h     | 3 ---
>  include/linux/highmem.h         | 8 +++++---
>  5 files changed, 5 insertions(+), 15 deletions(-)
>
> diff --git a/arch/alpha/include/asm/page.h b/arch/alpha/include/asm/page.h
> index 59d01f9b77f6..4327029cd660 100644
> --- a/arch/alpha/include/asm/page.h
> +++ b/arch/alpha/include/asm/page.h
> @@ -12,9 +12,6 @@
>
>  extern void clear_page(void *page);
>
> -#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
> -	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr)
> -
>  extern void copy_page(void * _to, void * _from);
>  #define copy_user_page(to, from, vaddr, pg)	copy_page(to, from)
>
> diff --git a/arch/m68k/include/asm/page_no.h b/arch/m68k/include/asm/page_no.h
> index d2532bc407ef..f511b763a235 100644
> --- a/arch/m68k/include/asm/page_no.h
> +++ b/arch/m68k/include/asm/page_no.h
> @@ -12,9 +12,6 @@ extern unsigned long memory_end;
>
>  #define copy_user_page(to, from, vaddr, pg)	copy_page(to, from)
>
> -#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
> -	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr)
> -
>  #define __pa(vaddr)		((unsigned long)(vaddr))
>  #define __va(paddr)		((void *)((unsigned long)(paddr)))
>
> diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
> index 56da819a79e6..e995d2a413f9 100644
> --- a/arch/s390/include/asm/page.h
> +++ b/arch/s390/include/asm/page.h
> @@ -67,9 +67,6 @@ static inline void copy_page(void *to, void *from)
>
>  #define copy_user_page(to, from, vaddr, pg)	copy_page(to, from)
>
> -#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
> -	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr)
> -
>  #ifdef CONFIG_STRICT_MM_TYPECHECKS
>  #define STRICT_MM_TYPECHECKS
>  #endif
> diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
> index 416dc88e35c1..92fa975b46f3 100644
> --- a/arch/x86/include/asm/page.h
> +++ b/arch/x86/include/asm/page.h
> @@ -28,9 +28,6 @@ static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
>  	copy_page(to, from);
>  }
>
> -#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
> -	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr)
> -
>  #ifndef __pa
>  #define __pa(x)		__phys_addr((unsigned long)(x))
>  #endif
> diff --git a/include/linux/highmem.h b/include/linux/highmem.h
> index 8b0afaabbc6e..642718a50c27 100644
> --- a/include/linux/highmem.h
> +++ b/include/linux/highmem.h
> @@ -303,7 +303,6 @@ static inline void clear_user_highpages(struct page *page, unsigned long vaddr,
>  #endif
>  }
>
> -#ifndef vma_alloc_zeroed_movable_folio

We're specifying this function unconditionally even though arm64 overrides?

>  /**
>   * vma_alloc_zeroed_movable_folio - Allocate a zeroed page for a VMA.
>   * @vma: The VMA the page is to be allocated for.
> @@ -317,12 +316,15 @@ static inline void clear_user_highpages(struct page *page, unsigned long vaddr,
>   * we are out of memory.
>   */
>  static inline
> -struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma,
> +struct folio *vma_alloc_zeroed_movable_folio_noprof(struct vm_area_struct *vma,
>  				   unsigned long vaddr)
>  {
> -	return vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO,
> +	return vma_alloc_folio_noprof(GFP_HIGHUSER_MOVABLE | __GFP_ZERO,
>  			      0, vma, vaddr);

This whole change seems unnecessary?

>  }
> +#ifndef vma_alloc_zeroed_movable_folio
> +#define vma_alloc_zeroed_movable_folio(...) \
> +	alloc_hooks(vma_alloc_zeroed_movable_folio_noprof(__VA_ARGS__))
>  #endif

I don't know why we need to add more of this alloc_hooks() dance when we could
just do:

#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr)

Like the existing arch stuff?

>
>  static inline void clear_highpage(struct page *page)
> --
> MST
>

Thanks, Lorenzo