Subject: Re: [PATCH v3 03/12] mm: Make HPAGE_PXD_* macros even if !THP

From: SeongJae Park <[email-masked]>
Date: Fri, 22 Mar 2024 10:14:56 -0700

Hi Peter,

On Thu, 21 Mar 2024 18:07:53 -0400 [email-masked] wrote:

> From: Peter Xu <[email-masked]>
> 
> These macros can be helpful when we plan to merge hugetlb code into generic
> code.  Move them out and define them even if !THP.
> 
> We actually already defined HPAGE_PMD_NR for other reasons even if !THP.
> Reorganize these macros.
> 
> Reviewed-by: Christoph Hellwig <[email-masked]>
> Reviewed-by: Jason Gunthorpe <[email-masked]>
> Signed-off-by: Peter Xu <[email-masked]>
> ---
>  include/linux/huge_mm.h | 17 ++++++-----------
>  1 file changed, 6 insertions(+), 11 deletions(-)
> 
> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> index de0c89105076..3bcdfc7e5d57 100644
> --- a/include/linux/huge_mm.h
> +++ b/include/linux/huge_mm.h
> @@ -64,9 +64,6 @@ ssize_t single_hugepage_flag_show(struct kobject *kobj,
>  				  enum transparent_hugepage_flag flag);
>  extern struct kobj_attribute shmem_enabled_attr;
>  
> -#define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
> -#define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER)
> -
>  /*
>   * Mask of all large folio orders supported for anonymous THP; all orders up to
>   * and including PMD_ORDER, except order-0 (which is not "huge") and order-1
> @@ -87,14 +84,19 @@ extern struct kobj_attribute shmem_enabled_attr;
>  #define thp_vma_allowable_order(vma, vm_flags, smaps, in_pf, enforce_sysfs, order) \
>  	(!!thp_vma_allowable_orders(vma, vm_flags, smaps, in_pf, enforce_sysfs, BIT(order)))
>  
> -#ifdef CONFIG_TRANSPARENT_HUGEPAGE
>  #define HPAGE_PMD_SHIFT PMD_SHIFT
>  #define HPAGE_PMD_SIZE	((1UL) << HPAGE_PMD_SHIFT)
>  #define HPAGE_PMD_MASK	(~(HPAGE_PMD_SIZE - 1))
> +#define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
> +#define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER)
>  
>  #define HPAGE_PUD_SHIFT PUD_SHIFT
>  #define HPAGE_PUD_SIZE	((1UL) << HPAGE_PUD_SHIFT)
>  #define HPAGE_PUD_MASK	(~(HPAGE_PUD_SIZE - 1))
> +#define HPAGE_PUD_ORDER (HPAGE_PUD_SHIFT-PAGE_SHIFT)
> +#define HPAGE_PUD_NR (1<<HPAGE_PUD_ORDER)

I just found latest mm-unstable fails one of my build configurations[1] with
below error.  'git bisect' says this is the first patch set started the
failure.  I haven't looked in deep, but just reporting first.

    In file included from .../include/linux/mm.h:1115,
                     from .../mm/vmstat.c:14:
    .../mm/vmstat.c: In function 'zoneinfo_show_print':
    .../include/linux/huge_mm.h:87:25: error: 'PMD_SHIFT' undeclared (first use in this function); did you mean 'PUD_SHIFT'?
       87 | #define HPAGE_PMD_SHIFT PMD_SHIFT
          |                         ^~~~~~~~~

[1] https://github.com/awslabs/damon-tests/blob/next/corr/tests/build_m68k.sh

Thanks,
SJ

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