RE:[PATCH 3/4] selftests/mm: add check_folio_orders() helper.

[wang lian <lianux.mm@gmail.com>]

Hi Zi,

Thanks for the patch.

I have a nit suggestion to centralize some of the macro definitions
for better consistency and reusability.

On [Date of patch], Zi Yan wrote:
> diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
> ...
> +#define PGMAP_PRESENT		(1UL << 63)
> +#define KPF_COMPOUND_HEAD	(1UL << 15)
> +#define KPF_COMPOUND_TAIL	(1UL << 16)
> +#define KPF_THP			(1UL << 22)
> +#define PFN_MASK		((1UL<<55)-1)

Currently, these macros and `PGMAP_PRESENT` are defined locally in
`vm_util.c`. It would be cleaner to move them to the shared header
`vm_util.h`.

This would also allow us to consistently use `PM_PRESENT` (from the
header) instead of the local `PGMAP_PRESENT` duplicate. I noticed the
patch is already moving in this direction, and we can complete this
cleanup.

How about a change like this?

--- a/tools/testing/selftests/mm/vm_util.c
+++ b/tools/testing/selftests/mm/vm_util.c
@@ -17,17 +17,6 @@
 #define STATUS_FILE_PATH "/proc/self/status"
 #define MAX_LINE_LENGTH 500
 
-#define PGMAP_PRESENT          (1UL << 63)
-#define KPF_COMPOUND_HEAD      (1UL << 15)
-#define KPF_COMPOUND_TAIL      (1UL << 16)
-#define KPF_THP                        (1UL << 22)
-#define PFN_MASK     ((1UL<<55)-1)
-
 unsigned int __page_size;
 unsigned int __page_shift;
 
@@ -360,7 +349,7 @@ static int get_page_flags(uint64_t vpn, int pagemap_file, int kpageflags_file,
 	 * Treat non-present page as a page without any flag, so that
 	 * gather_folio_orders() just record the current folio order.
 	 */
-	if (!(pfn & PGMAP_PRESENT)) {
+	if (!(pfn & PM_PRESENT)) {
 		*flags = 0;
 		return 0;
 	}
--- a/tools/testing/selftests/mm/vm_util.h
+++ b/tools/testing/selftests/mm/vm_util.h
@@ -17,6 +17,11 @@
 #define PM_FILE                        BIT_ULL(61)
 #define PM_SWAP                        BIT_ULL(62)
 #define PM_PRESENT             BIT_ULL(63)
+#define KPF_COMPOUND_HEAD      (1UL << 15)
+#define KPF_COMPOUND_TAIL      (1UL << 16)
+#define KPF_THP                        (1UL << 22)
+#define PFN_MASK     ((1UL<<55)-1)
 
 extern unsigned int __page_size;
 extern unsigned int __page_shift;


Best regards,
wang lian