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

Anshuman Khandual
2026-04-10T04:21:58Z

On 09/04/26 4:03 PM, Mike Rapoport wrote:
> 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 <akpm@linux-foundation.org>
>> Cc: David Hildenbrand <david@kernel.org>
>> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
>> Cc: Mike Rapoport <rppt@kernel.org>
>> Cc: linux-mm@kvack.org
>> Cc: linux-kernel@vger.kernel.org
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>> 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.

Sure will drop the indent from pxdval_t.

>
>> +#else
>> + typedef unsigned long long pxdval_t;
>> +#endif
>
> Don't we want this in, say, include/linux/pgtable.h?
>

Sure will move the typedef into the above header.