[PATCH v3 3/4] selftests: mm: implement the mTHP-sized hugepage check helpers

Implement mTHP-sized hugepage checking helpers using gather_folio_orders().
Also rename the existing PMD-sized huge page check function to
__check_pmd_huge() for clarity.

Reviewed-by: Nico Pache (Red Hat) <[email protected]>
Tested-by: Nico Pache (Red Hat) <[email protected]>
Acked-by: Kiryl Shutsemau (Meta) <[email protected]>
Signed-off-by: Baolin Wang <[email protected]>
---
 tools/testing/selftests/mm/vm_util.c | 76 ++++++++++++++++++++++++++--
 1 file changed, 72 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
index 5a427f494cd8..13b5cff7dfe3 100644
--- a/tools/testing/selftests/mm/vm_util.c
+++ b/tools/testing/selftests/mm/vm_util.c
@@ -15,6 +15,9 @@
 #define SMAP_FILE_PATH "/proc/self/smaps"
 #define STATUS_FILE_PATH "/proc/self/status"
 #define MAX_LINE_LENGTH 500
+#define PAGEMAP_PATH "/proc/self/pagemap"
+#define KPAGEFLAGS_PATH "/proc/kpageflags"
+#define MAX_NR_ORDERS 20
 
 unsigned int __page_size;
 unsigned int __page_shift;
@@ -348,7 +351,7 @@ char *__get_smap_entry(void *addr, const char *pattern, char *buf, size_t len)
 	return entry;
 }
 
-bool __check_huge(void *addr, char *pattern, int nr_hpages,
+static bool __check_pmd_huge(void *addr, char *pattern, int nr_hpages,
 		  uint64_t hpage_size)
 {
 	char buffer[MAX_LINE_LENGTH];
@@ -366,19 +369,84 @@ bool __check_huge(void *addr, char *pattern, int nr_hpages,
 	return thp == (nr_hpages * (hpage_size >> 10));
 }
 
+static bool check_large_folios(void *addr, size_t len, int nr_hpages,
+		uint64_t hpage_size)
+{
+	int order = 0, pagesize = getpagesize();
+	unsigned int nr_pages = hpage_size / pagesize;
+	int orders[MAX_NR_ORDERS], status;
+	int pagemap_fd, kpageflags_fd;
+	bool ret = false;
+
+	if (!nr_pages)
+		ksft_exit_fail_msg("invalid hugepage size\n");
+
+	order = 31 - __builtin_clz(nr_pages);
+	if (!order || order >= MAX_NR_ORDERS)
+		ksft_exit_fail_msg("invalid order\n");
+
+	memset(orders, 0, sizeof(int) * MAX_NR_ORDERS);
+	pagemap_fd = open(PAGEMAP_PATH, O_RDONLY);
+	if (pagemap_fd == -1)
+		ksft_exit_fail_msg("read pagemap fail\n");
+
+	kpageflags_fd = open(KPAGEFLAGS_PATH, O_RDONLY);
+	if (kpageflags_fd == -1) {
+		close(pagemap_fd);
+		ksft_exit_fail_msg("read kpageflags fail\n");
+	}
+
+	status = gather_folio_orders(addr, len, pagemap_fd,
+			kpageflags_fd, orders, MAX_NR_ORDERS);
+	if (status)
+		goto out;
+
+	if (orders[order] == nr_hpages)
+		ret = true;
+
+out:
+	close(pagemap_fd);
+	close(kpageflags_fd);
+	return ret;
+}
+
 bool check_huge_anon(void *addr, size_t len, int nr_hpages, uint64_t hpage_size)
 {
-	return __check_huge(addr, "AnonHugePages: ", nr_hpages, hpage_size);
+	uint64_t pmd_pagesize = read_pmd_pagesize();
+
+	if (!pmd_pagesize)
+		ksft_exit_fail_msg("reading PMD pagesize failed\n");
+
+	if (hpage_size == pmd_pagesize)
+		return __check_pmd_huge(addr, "AnonHugePages: ", nr_hpages, hpage_size);
+
+	return check_large_folios(addr, len, nr_hpages, hpage_size);
 }
 
 bool check_huge_file(void *addr, size_t len, int nr_hpages, uint64_t hpage_size)
 {
-	return __check_huge(addr, "FilePmdMapped:", nr_hpages, hpage_size);
+	uint64_t pmd_pagesize = read_pmd_pagesize();
+
+	if (!pmd_pagesize)
+		ksft_exit_fail_msg("reading PMD pagesize failed\n");
+
+	if (hpage_size == pmd_pagesize)
+		return __check_pmd_huge(addr, "FilePmdMapped:", nr_hpages, hpage_size);
+
+	return check_large_folios(addr, len, nr_hpages, hpage_size);
 }
 
 bool check_huge_shmem(void *addr, size_t len, int nr_hpages, uint64_t hpage_size)
 {
-	return __check_huge(addr, "ShmemPmdMapped:", nr_hpages, hpage_size);
+	uint64_t pmd_pagesize = read_pmd_pagesize();
+
+	if (!pmd_pagesize)
+		ksft_exit_fail_msg("reading PMD pagesize failed\n");
+
+	if (hpage_size == pmd_pagesize)
+		return __check_pmd_huge(addr, "ShmemPmdMapped:", nr_hpages, hpage_size);
+
+	return check_large_folios(addr, len, nr_hpages, hpage_size);
 }
 
 int64_t allocate_transhuge(void *ptr, int pagemap_fd)
-- 
2.47.3