selftests/mm: move HugeTLB helpers to hugepage_settings

Move library functions that abstract HugeTLB /proc and /sysfs access from
vm_util to hugepage_settings.

This will help creating common helpers that save and restore HugeTLB and
THP settings.

Link: https://lore.kernel.org/20260511162840.375890-25-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

tools/testing/selftests/mm/gup_longterm.c

@@ -29,6 +29,7 @@
 #include "../../../../mm/gup_test.h"
 #include "kselftest.h"
 #include "vm_util.h"
+#include "hugepage_settings.h"
 
 static size_t pagesize;
 static int nr_hugetlbsizes;

tools/testing/selftests/mm/hmm-tests.c

@@ -11,6 +11,7 @@
  */
 
 #include "kselftest_harness.h"
+#include "hugepage_settings.h"
 
 #include <errno.h>
 #include <fcntl.h>
@@ -27,7 +28,6 @@
 #include <sys/ioctl.h>
 #include <sys/time.h>
 
-
 /*
  * This is a private UAPI to the kernel test module so it isn't exported
  * in the usual include/uapi/... directory.

tools/testing/selftests/mm/hugepage_settings.c

@@ -1,7 +1,9 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <dirent.h>
 #include <fcntl.h>
 #include <limits.h>
 #include <signal.h>
+#include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -395,3 +397,69 @@ bool thp_is_enabled(void)
 	/* THP is considered enabled if it's either "always" or "madvise" */
 	return mode == 1 || mode == 3;
 }
+
+int detect_hugetlb_page_sizes(size_t sizes[], int max)
+{
+	DIR *dir = opendir("/sys/kernel/mm/hugepages/");
+	int count = 0;
+
+	if (!dir)
+		return 0;
+
+	while (count < max) {
+		struct dirent *entry = readdir(dir);
+		size_t kb;
+
+		if (!entry)
+			break;
+		if (entry->d_type != DT_DIR)
+			continue;
+		if (sscanf(entry->d_name, "hugepages-%zukB", &kb) != 1)
+			continue;
+		sizes[count++] = kb * 1024;
+		ksft_print_msg("[INFO] detected hugetlb page size: %zu KiB\n",
+			       kb);
+	}
+	closedir(dir);
+	return count;
+}
+
+unsigned long default_huge_page_size(void)
+{
+	unsigned long hps = 0;
+	char *line = NULL;
+	size_t linelen = 0;
+	FILE *f = fopen("/proc/meminfo", "r");
+
+	if (!f)
+		return 0;
+	while (getline(&line, &linelen, f) > 0) {
+		if (sscanf(line, "Hugepagesize:       %lu kB", &hps) == 1) {
+			hps <<= 10;
+			break;
+		}
+	}
+
+	free(line);
+	fclose(f);
+	return hps;
+}
+
+unsigned long get_free_hugepages(void)
+{
+	unsigned long fhp = 0;
+	char *line = NULL;
+	size_t linelen = 0;
+	FILE *f = fopen("/proc/meminfo", "r");
+
+	if (!f)
+		return fhp;
+	while (getline(&line, &linelen, f) > 0) {
+		if (sscanf(line, "HugePages_Free:      %lu", &fhp) == 1)
+			break;
+	}
+
+	free(line);
+	fclose(f);
+	return fhp;
+}

tools/testing/selftests/mm/hugepage_settings.h

@@ -6,6 +6,8 @@
 #include <stddef.h>
 #include <stdint.h>
 
+/* Transparent Huge Pages (THP) */
+
 enum thp_enabled {
 	THP_NEVER,
 	THP_ALWAYS,
@@ -86,4 +88,10 @@ unsigned long thp_shmem_supported_orders(void);
 bool thp_available(void);
 bool thp_is_enabled(void);
 
+/* HugeTLB */
+
+int detect_hugetlb_page_sizes(size_t sizes[], int max);
+unsigned long default_huge_page_size(void);
+unsigned long get_free_hugepages(void);
+
 #endif /* __HUGEPAGE_SETTINGS_H__ */

tools/testing/selftests/mm/hugetlb-madvise.c

@@ -20,6 +20,7 @@
 #include <fcntl.h>
 #include "vm_util.h"
 #include "kselftest.h"
+#include "hugepage_settings.h"
 
 #define MIN_FREE_PAGES	20
 #define NR_HUGE_PAGES	10	/* common number of pages to map/allocate */

tools/testing/selftests/mm/hugetlb-mmap.c

@@ -18,6 +18,7 @@
 #include <linux/memfd.h>
 #include "vm_util.h"
 #include "kselftest.h"
+#include "hugepage_settings.h"
 
 #define LENGTH (256UL*1024*1024)
 #define PROTECTION (PROT_READ | PROT_WRITE)

tools/testing/selftests/mm/hugetlb-vmemmap.c

@@ -11,6 +11,7 @@
 #include <sys/mman.h>
 #include <fcntl.h>
 #include "vm_util.h"
+#include "hugepage_settings.h"
 
 #define PAGE_COMPOUND_HEAD	(1UL << 15)
 #define PAGE_COMPOUND_TAIL	(1UL << 16)

tools/testing/selftests/mm/hugetlb_dio.c

@@ -20,6 +20,7 @@
 #include <sys/syscall.h>
 #include "vm_util.h"
 #include "kselftest.h"
+#include "hugepage_settings.h"
 
 #ifndef STATX_DIOALIGN
 #define STATX_DIOALIGN		0x00002000U

tools/testing/selftests/mm/hugetlb_fault_after_madv.c

@@ -10,6 +10,7 @@
 
 #include "vm_util.h"
 #include "kselftest.h"
+#include "hugepage_settings.h"
 
 #define INLOOP_ITER 100
 

tools/testing/selftests/mm/hugetlb_madv_vs_map.c

@@ -25,6 +25,7 @@
 #include <unistd.h>
 
 #include "vm_util.h"
+#include "hugepage_settings.h"
 
 #define INLOOP_ITER 100
 

tools/testing/selftests/mm/protection_keys.c

@@ -46,6 +46,7 @@
 #include <sys/ptrace.h>
 #include <setjmp.h>
 
+#include "hugepage_settings.h"
 #include "pkey-helpers.h"
 
 int iteration_nr = 1;

tools/testing/selftests/mm/thuge-gen.c

@@ -28,6 +28,7 @@
 #include <string.h>
 #include "vm_util.h"
 #include "kselftest.h"
+#include "hugepage_settings.h"
 
 #if !defined(MAP_HUGETLB)
 #define MAP_HUGETLB	0x40000

tools/testing/selftests/mm/uffd-common.h

@@ -37,6 +37,7 @@
 
 #include "kselftest.h"
 #include "vm_util.h"
+#include "hugepage_settings.h"
 
 #define UFFD_FLAGS	(O_CLOEXEC | O_NONBLOCK | UFFD_USER_MODE_ONLY)
 

tools/testing/selftests/mm/va_high_addr_switch.c

@@ -11,6 +11,7 @@
 
 #include "vm_util.h"
 #include "kselftest.h"
+#include "hugepage_settings.h"
 
 /*
  * The hint addr value is used to allocate addresses

tools/testing/selftests/mm/vm_util.c

@@ -2,7 +2,6 @@
 #include <string.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <dirent.h>
 #include <inttypes.h>
 #include <sys/ioctl.h>
 #include <linux/userfaultfd.h>
@@ -291,53 +290,6 @@ int64_t allocate_transhuge(void *ptr, int pagemap_fd)
 	return -1;
 }
 
-unsigned long default_huge_page_size(void)
-{
-	unsigned long hps = 0;
-	char *line = NULL;
-	size_t linelen = 0;
-	FILE *f = fopen("/proc/meminfo", "r");
-
-	if (!f)
-		return 0;
-	while (getline(&line, &linelen, f) > 0) {
-		if (sscanf(line, "Hugepagesize:       %lu kB", &hps) == 1) {
-			hps <<= 10;
-			break;
-		}
-	}
-
-	free(line);
-	fclose(f);
-	return hps;
-}
-
-int detect_hugetlb_page_sizes(size_t sizes[], int max)
-{
-	DIR *dir = opendir("/sys/kernel/mm/hugepages/");
-	int count = 0;
-
-	if (!dir)
-		return 0;
-
-	while (count < max) {
-		struct dirent *entry = readdir(dir);
-		size_t kb;
-
-		if (!entry)
-			break;
-		if (entry->d_type != DT_DIR)
-			continue;
-		if (sscanf(entry->d_name, "hugepages-%zukB", &kb) != 1)
-			continue;
-		sizes[count++] = kb * 1024;
-		ksft_print_msg("[INFO] detected hugetlb page size: %zu KiB\n",
-			       kb);
-	}
-	closedir(dir);
-	return count;
-}
-
 int pageflags_get(unsigned long pfn, int kpageflags_fd, uint64_t *flags)
 {
 	size_t count;
@@ -396,25 +348,6 @@ int uffd_unregister(int uffd, void *addr, uint64_t len)
 	return ret;
 }
 
-unsigned long get_free_hugepages(void)
-{
-	unsigned long fhp = 0;
-	char *line = NULL;
-	size_t linelen = 0;
-	FILE *f = fopen("/proc/meminfo", "r");
-
-	if (!f)
-		return fhp;
-	while (getline(&line, &linelen, f) > 0) {
-		if (sscanf(line, "HugePages_Free:      %lu", &fhp) == 1)
-			break;
-	}
-
-	free(line);
-	fclose(f);
-	return fhp;
-}
-
 static bool check_vmflag(void *addr, const char *flag)
 {
 	char buffer[MAX_LINE_LENGTH];

tools/testing/selftests/mm/vm_util.h

@@ -94,8 +94,6 @@ bool check_huge_anon(void *addr, int nr_hpages, uint64_t hpage_size);
 bool check_huge_file(void *addr, int nr_hpages, uint64_t hpage_size);
 bool check_huge_shmem(void *addr, int nr_hpages, uint64_t hpage_size);
 int64_t allocate_transhuge(void *ptr, int pagemap_fd);
-unsigned long default_huge_page_size(void);
-int detect_hugetlb_page_sizes(size_t sizes[], int max);
 int pageflags_get(unsigned long pfn, int kpageflags_fd, uint64_t *flags);
 
 int uffd_register(int uffd, void *addr, uint64_t len,
@@ -103,7 +101,6 @@ int uffd_register(int uffd, void *addr, uint64_t len,
 int uffd_unregister(int uffd, void *addr, uint64_t len);
 int uffd_register_with_ioctls(int uffd, void *addr, uint64_t len,
 			      bool miss, bool wp, bool minor, uint64_t *ioctls);
-unsigned long get_free_hugepages(void);
 bool check_vmflag_io(void *addr);
 bool check_vmflag_pfnmap(void *addr);
 bool check_vmflag_guard(void *addr);