Re: [PATCH Resend] mm: Refine __{pgd,p4d,pud,pmd,pte}_alloc_one_*() about HIGHMEM

Mike Rapoport
2025-11-09T07:44:47Z

On Fri, Nov 07, 2025 at 05:59:22PM +0800, Huacai Chen wrote:
> __{pgd,p4d,pud,pmd,pte}_alloc_one_*() always allocate pages with GFP
> flag GFP_PGTABLE_KERNEL/GFP_PGTABLE_USER. These two macros are defined
> as follows:
>
> #define GFP_PGTABLE_KERNEL (GFP_KERNEL | __GFP_ZERO)
> #define GFP_PGTABLE_USER (GFP_PGTABLE_KERNEL | __GFP_ACCOUNT)
>
> There is no __GFP_HIGHMEM in them, so we needn't to clear __GFP_HIGHMEM
> explicitly.
>
> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

> ---
> Resend because the lines begin with # was eaten by git.
>
> include/asm-generic/pgalloc.h | 6 +-----
> 1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/include/asm-generic/pgalloc.h b/include/asm-generic/pgalloc.h
> index 3c8ec3bfea44..706e87b43b19 100644
> --- a/include/asm-generic/pgalloc.h
> +++ b/include/asm-generic/pgalloc.h
> @@ -18,8 +18,7 @@
> */
> static inline pte_t *__pte_alloc_one_kernel_noprof(struct mm_struct *mm)
> {
> - struct ptdesc *ptdesc = pagetable_alloc_noprof(GFP_PGTABLE_KERNEL &
> - ~__GFP_HIGHMEM, 0);
> + struct ptdesc *ptdesc = pagetable_alloc_noprof(GFP_PGTABLE_KERNEL, 0);
>
> if (!ptdesc)
> return NULL;
> @@ -172,7 +171,6 @@ static inline pud_t *__pud_alloc_one_noprof(struct mm_struct *mm, unsigned long
>
> if (mm == &init_mm)
> gfp = GFP_PGTABLE_KERNEL;
> - gfp &= ~__GFP_HIGHMEM;
>
> ptdesc = pagetable_alloc_noprof(gfp, 0);
> if (!ptdesc)
> @@ -226,7 +224,6 @@ static inline p4d_t *__p4d_alloc_one_noprof(struct mm_struct *mm, unsigned long
>
> if (mm == &init_mm)
> gfp = GFP_PGTABLE_KERNEL;
> - gfp &= ~__GFP_HIGHMEM;
>
> ptdesc = pagetable_alloc_noprof(gfp, 0);
> if (!ptdesc)
> @@ -270,7 +267,6 @@ static inline pgd_t *__pgd_alloc_noprof(struct mm_struct *mm, unsigned int order
>
> if (mm == &init_mm)
> gfp = GFP_PGTABLE_KERNEL;
> - gfp &= ~__GFP_HIGHMEM;
>
> ptdesc = pagetable_alloc_noprof(gfp, order);
> if (!ptdesc)
> --
> 2.47.3
>

--
Sincerely yours,
Mike.