Subject: Re: [RFC V1 01/16] mm: Abstract printing of pxd_val()

From: Mike Rapoport <[email-masked]>
Date: Thu, 9 Apr 2026 13:33:41 +0300

Hi Anshuman,

On Tue, Feb 24, 2026 at 10:41:38AM +0530, Anshuman Khandual wrote:
> Ahead of adding support for D128 pgtables, refactor places that print
> PTE values to use the new __PRIpte format specifier and __PRIpte_args()
> macro to prepare the argument(s). When using D128 pgtables in future,
> we can simply redefine __PRIpte and __PTIpte_args().
> 
> Besides there is also an assumption about pxd_val() being always capped
> at 'unsigned long long' size but that will not work for D128 pgtables.
> Just increase its size to u128 if the compiler supports via a separate
> data type pxdval_t which also defaults to existing 'unsigned long long'.
> 
> Cc: Andrew Morton <[email-masked]>
> Cc: David Hildenbrand <[email-masked]>
> Cc: Lorenzo Stoakes <[email-masked]>
> Cc: Mike Rapoport <[email-masked]>
> Cc: [email-masked]
> Cc: [email-masked]
> Signed-off-by: Anshuman Khandual <[email-masked]>
> ---
>  include/linux/pgtable.h |  5 +++++
>  mm/memory.c             | 29 +++++++++++++++++++----------
>  2 files changed, 24 insertions(+), 10 deletions(-)
> 
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index a50df42a893f..da17139a1279 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -17,6 +17,11 @@
>  #include <asm-generic/pgtable_uffd.h>
>  #include <linux/page_table_check.h>
>  
> +#ifndef __PRIpte
> +#define __PRIpte		"016llx"
> +#define __PRIpte_args(val)	((u64)val)
> +#endif
> +
>  #if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \
>  	defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS
>  #error CONFIG_PGTABLE_LEVELS is not consistent with __PAGETABLE_{P4D,PUD,PMD}_FOLDED
> diff --git a/mm/memory.c b/mm/memory.c
> index 07778814b4a8..cfc3077fc52f 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -532,9 +532,15 @@ static bool is_bad_page_map_ratelimited(void)
>  	return false;
>  }
>  
> +#ifdef __SIZEOF_INT128__
> +	typedef u128 pxdval_t;

I don't think the typedef should be indented.

> +#else
> +	typedef unsigned long long pxdval_t;
> +#endif

Don't we want this in, say, include/linux/pgtable.h?

-- 
Sincerely yours,
Mike.