[RFC PATCH v2 10/11] selftests: mm: implement the mTHP-sized hugepage check helpers

[Baolin Wang <baolin.wang@linux.alibaba.com>]

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.

Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
---
 tools/testing/selftests/mm/vm_util.c | 55 ++++++++++++++++++++++++++--
 1 file changed, 51 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
index b08bf655ab23..6d464d49f164 100644
--- a/tools/testing/selftests/mm/vm_util.c
+++ b/tools/testing/selftests/mm/vm_util.c
@@ -15,6 +15,10 @@
 #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 GET_ORDER(nr_pages)    (31 - __builtin_clz(nr_pages))
+#define NR_ORDERS 20
 
 unsigned int __page_size;
 unsigned int __page_shift;
@@ -352,7 +356,7 @@ 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];
@@ -370,19 +374,62 @@ bool __check_huge(void *addr, char *pattern, int nr_hpages,
 	return thp == (nr_hpages * (hpage_size >> 10));
 }
 
+static bool check_large_folios(void *addr, unsigned long size, int nr_hpages, uint64_t hpage_size)
+{
+	int pagesize = getpagesize();
+	int order = GET_ORDER(hpage_size / pagesize);
+	int pagemap_fd, kpageflags_fd;
+	int orders[NR_ORDERS], status;
+	bool ret = false;
+
+	memset(orders, 0, sizeof(int) * 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, size, pagemap_fd,
+			kpageflags_fd, orders, 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, unsigned long size, int nr_hpages, uint64_t hpage_size)
 {
-	return __check_huge(addr, "AnonHugePages: ", nr_hpages, hpage_size);
+	if (hpage_size == read_pmd_pagesize())
+		return __check_pmd_huge(addr, "AnonHugePages: ", nr_hpages, hpage_size);
+
+	return check_large_folios(addr, size, nr_hpages, hpage_size);
 }
 
 bool check_huge_file(void *addr, unsigned long size, int nr_hpages, uint64_t hpage_size)
 {
-	return __check_huge(addr, "FilePmdMapped:", nr_hpages, hpage_size);
+	if (hpage_size == read_pmd_pagesize())
+		return __check_pmd_huge(addr, "FilePmdMapped:", nr_hpages, hpage_size);
+
+	return check_large_folios(addr, size, nr_hpages, hpage_size);
 }
 
 bool check_huge_shmem(void *addr, unsigned long size, int nr_hpages, uint64_t hpage_size)
 {
-	return __check_huge(addr, "ShmemPmdMapped:", nr_hpages, hpage_size);
+	if (hpage_size == read_pmd_pagesize())
+		return __check_pmd_huge(addr, "ShmemPmdMapped:", nr_hpages, hpage_size);
+
+	return check_large_folios(addr, size, nr_hpages, hpage_size);
 }
 
 int64_t allocate_transhuge(void *ptr, int pagemap_fd)
-- 
2.47.3