diff mbox series

[V4,1/2] selftests: vm: bring common functions to a new file

Message ID 20220315085014.1047291-1-usama.anjum@collabora.com (mailing list archive)
State New
Headers show
Series [V4,1/2] selftests: vm: bring common functions to a new file | expand

Commit Message

Muhammad Usama Anjum March 15, 2022, 8:50 a.m. UTC 
Bring common functions to a new file. These functions can be used in the
new tests. This helps in code duplication.

Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
---
 tools/testing/selftests/vm/Makefile           |   7 +-
 tools/testing/selftests/vm/madv_populate.c    |  34 +-----
 .../selftests/vm/split_huge_page_test.c       |  77 +------------
 tools/testing/selftests/vm/vm_util.c          | 103 ++++++++++++++++++
 tools/testing/selftests/vm/vm_util.h          |  15 +++
 5 files changed, 125 insertions(+), 111 deletions(-)
 create mode 100644 tools/testing/selftests/vm/vm_util.c
 create mode 100644 tools/testing/selftests/vm/vm_util.h

Comments

David Hildenbrand March 16, 2022, 8:55 a.m. UTC | #1 
On 15.03.22 09:50, Muhammad Usama Anjum wrote:
> Bring common functions to a new file. These functions can be used in the
> new tests. This helps in code duplication.
> 
> Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
> ---
>  tools/testing/selftests/vm/Makefile           |   7 +-
>  tools/testing/selftests/vm/madv_populate.c    |  34 +-----
>  .../selftests/vm/split_huge_page_test.c       |  77 +------------
>  tools/testing/selftests/vm/vm_util.c          | 103 ++++++++++++++++++
>  tools/testing/selftests/vm/vm_util.h          |  15 +++
>  5 files changed, 125 insertions(+), 111 deletions(-)
>  create mode 100644 tools/testing/selftests/vm/vm_util.c
>  create mode 100644 tools/testing/selftests/vm/vm_util.h
> 
> diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
> index 5e43f072f5b76..4e68edb26d6b6 100644
> --- a/tools/testing/selftests/vm/Makefile
> +++ b/tools/testing/selftests/vm/Makefile
> @@ -34,7 +34,7 @@ TEST_GEN_FILES += hugepage-mremap
>  TEST_GEN_FILES += hugepage-shm
>  TEST_GEN_FILES += hugepage-vmemmap
>  TEST_GEN_FILES += khugepaged
> -TEST_GEN_FILES += madv_populate
> +TEST_GEN_PROGS = madv_populate
>  TEST_GEN_FILES += map_fixed_noreplace
>  TEST_GEN_FILES += map_hugetlb
>  TEST_GEN_FILES += map_populate
> @@ -47,7 +47,7 @@ TEST_GEN_FILES += on-fault-limit
>  TEST_GEN_FILES += thuge-gen
>  TEST_GEN_FILES += transhuge-stress
>  TEST_GEN_FILES += userfaultfd
> -TEST_GEN_FILES += split_huge_page_test
> +TEST_GEN_PROGS += split_huge_page_test
>  TEST_GEN_FILES += ksm_tests
>  
>  ifeq ($(MACHINE),x86_64)
> @@ -91,6 +91,9 @@ TEST_FILES := test_vmalloc.sh
>  KSFT_KHDR_INSTALL := 1
>  include ../lib.mk
>  
> +$(OUTPUT)/madv_populate: vm_util.c
> +$(OUTPUT)/split_huge_page_test: vm_util.c
> +


[...]

> +// SPDX-License-Identifier: GPL-2.0
> +#include <stdbool.h>
> +#include <string.h>
> +#include "vm_util.h"
> +
> +uint64_t pagemap_get_entry(int fd, char *start)
> +{
> +	const unsigned long pfn = (unsigned long)start / getpagesize();
> +	uint64_t entry;
> +	int ret;
> +
> +	ret = pread(fd, &entry, sizeof(entry), pfn * sizeof(entry));
> +	if (ret != sizeof(entry))
> +		ksft_exit_fail_msg("reading pagemap failed\n");
> +	return entry;
> +}
> +
> +bool pagemap_is_softdirty(int fd, char *start)
> +{
> +	uint64_t entry = pagemap_get_entry(fd, start);
> +
> +	return ((entry >> DIRTY_BIT_LOCATION) & 1);
> +}

Please leave code you're moving around as untouched as possible to avoid
unrelated bugs that happen by mistake and are hard to review.

> +
> +void clear_softdirty(void)
> +{
> +	int ret;
> +	const char *ctrl = "4";
> +	int fd = open("/proc/self/clear_refs", O_WRONLY);
> +
> +	if (fd < 0)
> +		ksft_exit_fail_msg("opening clear_refs failed\n");
> +	ret = write(fd, ctrl, strlen(ctrl));
> +	close(fd);
> +	if (ret != strlen(ctrl))
> +		ksft_exit_fail_msg("writing clear_refs failed\n");
> +}
> +
> +
> +static bool check_for_pattern(FILE *fp, const char *pattern, char *buf)
> +{
> +	while (fgets(buf, MAX_LINE_LENGTH, fp) != NULL) {
> +		if (!strncmp(buf, pattern, strlen(pattern)))
> +			return true;
> +	}
> +	return false;
> +}
> +
> +uint64_t read_pmd_pagesize(void)
> +{
> +	int fd;
> +	char buf[20];
> +	ssize_t num_read;
> +
> +	fd = open(PMD_SIZE, O_RDONLY);
> +	if (fd == -1)
> +		ksft_exit_fail_msg("Open hpage_pmd_size failed\n");
> +
> +	num_read = read(fd, buf, 19);
> +	if (num_read < 1) {
> +		close(fd);
> +		ksft_exit_fail_msg("Read hpage_pmd_size failed\n");
> +	}
> +	buf[num_read] = '\0';
> +	close(fd);
> +
> +	return strtoul(buf, NULL, 10);
> +}
> +
> +uint64_t check_huge(void *addr)
> +{
> +	uint64_t thp = 0;
> +	int ret;
> +	FILE *fp;
> +	char buffer[MAX_LINE_LENGTH];
> +	char addr_pattern[MAX_LINE_LENGTH];
> +
> +	ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-",
> +		       (unsigned long) addr);
> +	if (ret >= MAX_LINE_LENGTH)
> +		ksft_exit_fail_msg("%s: Pattern is too long\n", __func__);
> +
> +	fp = fopen(SMAP, "r");
> +	if (!fp)
> +		ksft_exit_fail_msg("%s: Failed to open file %s\n", __func__, SMAP);
> +
> +	if (!check_for_pattern(fp, addr_pattern, buffer))
> +		goto err_out;
> +
> +	/*
> +	 * Fetch the AnonHugePages: in the same block and check the number of
> +	 * hugepages.
> +	 */
> +	if (!check_for_pattern(fp, "AnonHugePages:", buffer))
> +		goto err_out;
> +
> +	if (sscanf(buffer, "AnonHugePages:%10ld kB", &thp) != 1)
> +		ksft_exit_fail_msg("Reading smap error\n");
> +
> +err_out:
> +	fclose(fp);
> +	return thp;
> +}
> diff --git a/tools/testing/selftests/vm/vm_util.h b/tools/testing/selftests/vm/vm_util.h
> new file mode 100644
> index 0000000000000..7522dbb859f0f
> --- /dev/null
> +++ b/tools/testing/selftests/vm/vm_util.h
> @@ -0,0 +1,15 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#include <stdint.h>
> +#include <fcntl.h>
> +#include "../kselftest.h"
> +
> +#define	PMD_SIZE		"/sys/kernel/mm/transparent_hugepage/hpage_pmd_size"

Ehm no. PMD_SIZE_PATH at best -- just as it used to.

> +#define	SMAP			"/proc/self/smaps"

SMAPS_PATH

> +#define	DIRTY_BIT_LOCATION	55

Please inline that just as it used to. There is no value in a magic
define without any proper namespace.

> +#define	MAX_LINE_LENGTH		512

This used to be 500. Why the change?


Also: weird indentation and these all look like the should go into
vm_util.c. They are not used outside that file.
Muhammad Usama Anjum March 16, 2022, 4:47 p.m. UTC | #2 
Hi David,

Thank you for the review. I'll correct everything mentioned here in the
next iteration.

+[Gabriel]

On 3/16/22 1:55 PM, David Hildenbrand wrote:
> On 15.03.22 09:50, Muhammad Usama Anjum wrote:
>> Bring common functions to a new file. These functions can be used in the
>> new tests. This helps in code duplication.
>>
>> Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
>> ---
>>  tools/testing/selftests/vm/Makefile           |   7 +-
>>  tools/testing/selftests/vm/madv_populate.c    |  34 +-----
>>  .../selftests/vm/split_huge_page_test.c       |  77 +------------
>>  tools/testing/selftests/vm/vm_util.c          | 103 ++++++++++++++++++
>>  tools/testing/selftests/vm/vm_util.h          |  15 +++
>>  5 files changed, 125 insertions(+), 111 deletions(-)
>>  create mode 100644 tools/testing/selftests/vm/vm_util.c
>>  create mode 100644 tools/testing/selftests/vm/vm_util.h
>>
>> diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
>> index 5e43f072f5b76..4e68edb26d6b6 100644
>> --- a/tools/testing/selftests/vm/Makefile
>> +++ b/tools/testing/selftests/vm/Makefile
>> @@ -34,7 +34,7 @@ TEST_GEN_FILES += hugepage-mremap
>>  TEST_GEN_FILES += hugepage-shm
>>  TEST_GEN_FILES += hugepage-vmemmap
>>  TEST_GEN_FILES += khugepaged
>> -TEST_GEN_FILES += madv_populate
>> +TEST_GEN_PROGS = madv_populate
>>  TEST_GEN_FILES += map_fixed_noreplace
>>  TEST_GEN_FILES += map_hugetlb
>>  TEST_GEN_FILES += map_populate
>> @@ -47,7 +47,7 @@ TEST_GEN_FILES += on-fault-limit
>>  TEST_GEN_FILES += thuge-gen
>>  TEST_GEN_FILES += transhuge-stress
>>  TEST_GEN_FILES += userfaultfd
>> -TEST_GEN_FILES += split_huge_page_test
>> +TEST_GEN_PROGS += split_huge_page_test
>>  TEST_GEN_FILES += ksm_tests
>>  
>>  ifeq ($(MACHINE),x86_64)
>> @@ -91,6 +91,9 @@ TEST_FILES := test_vmalloc.sh
>>  KSFT_KHDR_INSTALL := 1
>>  include ../lib.mk
>>  
>> +$(OUTPUT)/madv_populate: vm_util.c
>> +$(OUTPUT)/split_huge_page_test: vm_util.c
>> +
> 
> 
> [...]
> 
>> +// SPDX-License-Identifier: GPL-2.0
>> +#include <stdbool.h>
>> +#include <string.h>
>> +#include "vm_util.h"
>> +
>> +uint64_t pagemap_get_entry(int fd, char *start)
>> +{
>> +	const unsigned long pfn = (unsigned long)start / getpagesize();
>> +	uint64_t entry;
>> +	int ret;
>> +
>> +	ret = pread(fd, &entry, sizeof(entry), pfn * sizeof(entry));
>> +	if (ret != sizeof(entry))
>> +		ksft_exit_fail_msg("reading pagemap failed\n");
>> +	return entry;
>> +}
>> +
>> +bool pagemap_is_softdirty(int fd, char *start)
>> +{
>> +	uint64_t entry = pagemap_get_entry(fd, start);
>> +
>> +	return ((entry >> DIRTY_BIT_LOCATION) & 1);
>> +}
> 
> Please leave code you're moving around as untouched as possible to avoid
> unrelated bugs that happen by mistake and are hard to review.
> 
>> +
>> +void clear_softdirty(void)
>> +{
>> +	int ret;
>> +	const char *ctrl = "4";
>> +	int fd = open("/proc/self/clear_refs", O_WRONLY);
>> +
>> +	if (fd < 0)
>> +		ksft_exit_fail_msg("opening clear_refs failed\n");
>> +	ret = write(fd, ctrl, strlen(ctrl));
>> +	close(fd);
>> +	if (ret != strlen(ctrl))
>> +		ksft_exit_fail_msg("writing clear_refs failed\n");
>> +}
>> +
>> +
>> +static bool check_for_pattern(FILE *fp, const char *pattern, char *buf)
>> +{
>> +	while (fgets(buf, MAX_LINE_LENGTH, fp) != NULL) {
>> +		if (!strncmp(buf, pattern, strlen(pattern)))
>> +			return true;
>> +	}
>> +	return false;
>> +}
>> +
>> +uint64_t read_pmd_pagesize(void)
>> +{
>> +	int fd;
>> +	char buf[20];
>> +	ssize_t num_read;
>> +
>> +	fd = open(PMD_SIZE, O_RDONLY);
>> +	if (fd == -1)
>> +		ksft_exit_fail_msg("Open hpage_pmd_size failed\n");
>> +
>> +	num_read = read(fd, buf, 19);
>> +	if (num_read < 1) {
>> +		close(fd);
>> +		ksft_exit_fail_msg("Read hpage_pmd_size failed\n");
>> +	}
>> +	buf[num_read] = '\0';
>> +	close(fd);
>> +
>> +	return strtoul(buf, NULL, 10);
>> +}
>> +
>> +uint64_t check_huge(void *addr)
>> +{
>> +	uint64_t thp = 0;
>> +	int ret;
>> +	FILE *fp;
>> +	char buffer[MAX_LINE_LENGTH];
>> +	char addr_pattern[MAX_LINE_LENGTH];
>> +
>> +	ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-",
>> +		       (unsigned long) addr);
>> +	if (ret >= MAX_LINE_LENGTH)
>> +		ksft_exit_fail_msg("%s: Pattern is too long\n", __func__);
>> +
>> +	fp = fopen(SMAP, "r");
>> +	if (!fp)
>> +		ksft_exit_fail_msg("%s: Failed to open file %s\n", __func__, SMAP);
>> +
>> +	if (!check_for_pattern(fp, addr_pattern, buffer))
>> +		goto err_out;
>> +
>> +	/*
>> +	 * Fetch the AnonHugePages: in the same block and check the number of
>> +	 * hugepages.
>> +	 */
>> +	if (!check_for_pattern(fp, "AnonHugePages:", buffer))
>> +		goto err_out;
>> +
>> +	if (sscanf(buffer, "AnonHugePages:%10ld kB", &thp) != 1)
>> +		ksft_exit_fail_msg("Reading smap error\n");
>> +
>> +err_out:
>> +	fclose(fp);
>> +	return thp;
>> +}
>> diff --git a/tools/testing/selftests/vm/vm_util.h b/tools/testing/selftests/vm/vm_util.h
>> new file mode 100644
>> index 0000000000000..7522dbb859f0f
>> --- /dev/null
>> +++ b/tools/testing/selftests/vm/vm_util.h
>> @@ -0,0 +1,15 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +#include <stdint.h>
>> +#include <fcntl.h>
>> +#include "../kselftest.h"
>> +
>> +#define	PMD_SIZE		"/sys/kernel/mm/transparent_hugepage/hpage_pmd_size"
> 
> Ehm no. PMD_SIZE_PATH at best -- just as it used to.
> 
>> +#define	SMAP			"/proc/self/smaps"
> 
> SMAPS_PATH
> 
>> +#define	DIRTY_BIT_LOCATION	55
> 
> Please inline that just as it used to. There is no value in a magic
> define without any proper namespace.
> 
>> +#define	MAX_LINE_LENGTH		512
> 
> This used to be 500. Why the change?
> 
> 
> Also: weird indentation and these all look like the should go into
> vm_util.c. They are not used outside that file.
> 
> 
>
diff mbox series

Patch

diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
index 5e43f072f5b76..4e68edb26d6b6 100644
--- a/tools/testing/selftests/vm/Makefile
+++ b/tools/testing/selftests/vm/Makefile
@@ -34,7 +34,7 @@  TEST_GEN_FILES += hugepage-mremap
 TEST_GEN_FILES += hugepage-shm
 TEST_GEN_FILES += hugepage-vmemmap
 TEST_GEN_FILES += khugepaged
-TEST_GEN_FILES += madv_populate
+TEST_GEN_PROGS = madv_populate
 TEST_GEN_FILES += map_fixed_noreplace
 TEST_GEN_FILES += map_hugetlb
 TEST_GEN_FILES += map_populate
@@ -47,7 +47,7 @@  TEST_GEN_FILES += on-fault-limit
 TEST_GEN_FILES += thuge-gen
 TEST_GEN_FILES += transhuge-stress
 TEST_GEN_FILES += userfaultfd
-TEST_GEN_FILES += split_huge_page_test
+TEST_GEN_PROGS += split_huge_page_test
 TEST_GEN_FILES += ksm_tests
 
 ifeq ($(MACHINE),x86_64)
@@ -91,6 +91,9 @@  TEST_FILES := test_vmalloc.sh
 KSFT_KHDR_INSTALL := 1
 include ../lib.mk
 
+$(OUTPUT)/madv_populate: vm_util.c
+$(OUTPUT)/split_huge_page_test: vm_util.c
+
 ifeq ($(MACHINE),x86_64)
 BINARIES_32 := $(patsubst %,$(OUTPUT)/%,$(BINARIES_32))
 BINARIES_64 := $(patsubst %,$(OUTPUT)/%,$(BINARIES_64))
diff --git a/tools/testing/selftests/vm/madv_populate.c b/tools/testing/selftests/vm/madv_populate.c
index 3ee0e82756002..715a42e8e2cdb 100644
--- a/tools/testing/selftests/vm/madv_populate.c
+++ b/tools/testing/selftests/vm/madv_populate.c
@@ -18,6 +18,7 @@ 
 #include <sys/mman.h>
 
 #include "../kselftest.h"
+#include "vm_util.h"
 
 /*
  * For now, we're using 2 MiB of private anonymous memory for all tests.
@@ -26,18 +27,6 @@ 
 
 static size_t pagesize;
 
-static uint64_t pagemap_get_entry(int fd, char *start)
-{
-	const unsigned long pfn = (unsigned long)start / pagesize;
-	uint64_t entry;
-	int ret;
-
-	ret = pread(fd, &entry, sizeof(entry), pfn * sizeof(entry));
-	if (ret != sizeof(entry))
-		ksft_exit_fail_msg("reading pagemap failed\n");
-	return entry;
-}
-
 static bool pagemap_is_populated(int fd, char *start)
 {
 	uint64_t entry = pagemap_get_entry(fd, start);
@@ -46,13 +35,6 @@  static bool pagemap_is_populated(int fd, char *start)
 	return entry & 0xc000000000000000ull;
 }
 
-static bool pagemap_is_softdirty(int fd, char *start)
-{
-	uint64_t entry = pagemap_get_entry(fd, start);
-
-	return entry & 0x0080000000000000ull;
-}
-
 static void sense_support(void)
 {
 	char *addr;
@@ -258,20 +240,6 @@  static bool range_is_not_softdirty(char *start, ssize_t size)
 	return ret;
 }
 
-static void clear_softdirty(void)
-{
-	int fd = open("/proc/self/clear_refs", O_WRONLY);
-	const char *ctrl = "4";
-	int ret;
-
-	if (fd < 0)
-		ksft_exit_fail_msg("opening clear_refs failed\n");
-	ret = write(fd, ctrl, strlen(ctrl));
-	if (ret != strlen(ctrl))
-		ksft_exit_fail_msg("writing clear_refs failed\n");
-	close(fd);
-}
-
 static void test_softdirty(void)
 {
 	char *addr;
diff --git a/tools/testing/selftests/vm/split_huge_page_test.c b/tools/testing/selftests/vm/split_huge_page_test.c
index 52497b7b9f1db..b6b381611fb6d 100644
--- a/tools/testing/selftests/vm/split_huge_page_test.c
+++ b/tools/testing/selftests/vm/split_huge_page_test.c
@@ -16,6 +16,7 @@ 
 #include <sys/mount.h>
 #include <malloc.h>
 #include <stdbool.h>
+#include "vm_util.h"
 
 uint64_t pagesize;
 unsigned int pageshift;
@@ -51,30 +52,6 @@  int is_backed_by_thp(char *vaddr, int pagemap_file, int kpageflags_file)
 	return 0;
 }
 
-
-static uint64_t read_pmd_pagesize(void)
-{
-	int fd;
-	char buf[20];
-	ssize_t num_read;
-
-	fd = open(PMD_SIZE_PATH, O_RDONLY);
-	if (fd == -1) {
-		perror("Open hpage_pmd_size failed");
-		exit(EXIT_FAILURE);
-	}
-	num_read = read(fd, buf, 19);
-	if (num_read < 1) {
-		close(fd);
-		perror("Read hpage_pmd_size failed");
-		exit(EXIT_FAILURE);
-	}
-	buf[num_read] = '\0';
-	close(fd);
-
-	return strtoul(buf, NULL, 10);
-}
-
 static int write_file(const char *path, const char *buf, size_t buflen)
 {
 	int fd;
@@ -113,58 +90,6 @@  static void write_debugfs(const char *fmt, ...)
 	}
 }
 
-#define MAX_LINE_LENGTH 500
-
-static bool check_for_pattern(FILE *fp, const char *pattern, char *buf)
-{
-	while (fgets(buf, MAX_LINE_LENGTH, fp) != NULL) {
-		if (!strncmp(buf, pattern, strlen(pattern)))
-			return true;
-	}
-	return false;
-}
-
-static uint64_t check_huge(void *addr)
-{
-	uint64_t thp = 0;
-	int ret;
-	FILE *fp;
-	char buffer[MAX_LINE_LENGTH];
-	char addr_pattern[MAX_LINE_LENGTH];
-
-	ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-",
-		       (unsigned long) addr);
-	if (ret >= MAX_LINE_LENGTH) {
-		printf("%s: Pattern is too long\n", __func__);
-		exit(EXIT_FAILURE);
-	}
-
-
-	fp = fopen(SMAP_PATH, "r");
-	if (!fp) {
-		printf("%s: Failed to open file %s\n", __func__, SMAP_PATH);
-		exit(EXIT_FAILURE);
-	}
-	if (!check_for_pattern(fp, addr_pattern, buffer))
-		goto err_out;
-
-	/*
-	 * Fetch the AnonHugePages: in the same block and check the number of
-	 * hugepages.
-	 */
-	if (!check_for_pattern(fp, "AnonHugePages:", buffer))
-		goto err_out;
-
-	if (sscanf(buffer, "AnonHugePages:%10ld kB", &thp) != 1) {
-		printf("Reading smap error\n");
-		exit(EXIT_FAILURE);
-	}
-
-err_out:
-	fclose(fp);
-	return thp;
-}
-
 void split_pmd_thp(void)
 {
 	char *one_page;
diff --git a/tools/testing/selftests/vm/vm_util.c b/tools/testing/selftests/vm/vm_util.c
new file mode 100644
index 0000000000000..c946e04df9236
--- /dev/null
+++ b/tools/testing/selftests/vm/vm_util.c
@@ -0,0 +1,103 @@ 
+// SPDX-License-Identifier: GPL-2.0
+#include <stdbool.h>
+#include <string.h>
+#include "vm_util.h"
+
+uint64_t pagemap_get_entry(int fd, char *start)
+{
+	const unsigned long pfn = (unsigned long)start / getpagesize();
+	uint64_t entry;
+	int ret;
+
+	ret = pread(fd, &entry, sizeof(entry), pfn * sizeof(entry));
+	if (ret != sizeof(entry))
+		ksft_exit_fail_msg("reading pagemap failed\n");
+	return entry;
+}
+
+bool pagemap_is_softdirty(int fd, char *start)
+{
+	uint64_t entry = pagemap_get_entry(fd, start);
+
+	return ((entry >> DIRTY_BIT_LOCATION) & 1);
+}
+
+void clear_softdirty(void)
+{
+	int ret;
+	const char *ctrl = "4";
+	int fd = open("/proc/self/clear_refs", O_WRONLY);
+
+	if (fd < 0)
+		ksft_exit_fail_msg("opening clear_refs failed\n");
+	ret = write(fd, ctrl, strlen(ctrl));
+	close(fd);
+	if (ret != strlen(ctrl))
+		ksft_exit_fail_msg("writing clear_refs failed\n");
+}
+
+
+static bool check_for_pattern(FILE *fp, const char *pattern, char *buf)
+{
+	while (fgets(buf, MAX_LINE_LENGTH, fp) != NULL) {
+		if (!strncmp(buf, pattern, strlen(pattern)))
+			return true;
+	}
+	return false;
+}
+
+uint64_t read_pmd_pagesize(void)
+{
+	int fd;
+	char buf[20];
+	ssize_t num_read;
+
+	fd = open(PMD_SIZE, O_RDONLY);
+	if (fd == -1)
+		ksft_exit_fail_msg("Open hpage_pmd_size failed\n");
+
+	num_read = read(fd, buf, 19);
+	if (num_read < 1) {
+		close(fd);
+		ksft_exit_fail_msg("Read hpage_pmd_size failed\n");
+	}
+	buf[num_read] = '\0';
+	close(fd);
+
+	return strtoul(buf, NULL, 10);
+}
+
+uint64_t check_huge(void *addr)
+{
+	uint64_t thp = 0;
+	int ret;
+	FILE *fp;
+	char buffer[MAX_LINE_LENGTH];
+	char addr_pattern[MAX_LINE_LENGTH];
+
+	ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-",
+		       (unsigned long) addr);
+	if (ret >= MAX_LINE_LENGTH)
+		ksft_exit_fail_msg("%s: Pattern is too long\n", __func__);
+
+	fp = fopen(SMAP, "r");
+	if (!fp)
+		ksft_exit_fail_msg("%s: Failed to open file %s\n", __func__, SMAP);
+
+	if (!check_for_pattern(fp, addr_pattern, buffer))
+		goto err_out;
+
+	/*
+	 * Fetch the AnonHugePages: in the same block and check the number of
+	 * hugepages.
+	 */
+	if (!check_for_pattern(fp, "AnonHugePages:", buffer))
+		goto err_out;
+
+	if (sscanf(buffer, "AnonHugePages:%10ld kB", &thp) != 1)
+		ksft_exit_fail_msg("Reading smap error\n");
+
+err_out:
+	fclose(fp);
+	return thp;
+}
diff --git a/tools/testing/selftests/vm/vm_util.h b/tools/testing/selftests/vm/vm_util.h
new file mode 100644
index 0000000000000..7522dbb859f0f
--- /dev/null
+++ b/tools/testing/selftests/vm/vm_util.h
@@ -0,0 +1,15 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <stdint.h>
+#include <fcntl.h>
+#include "../kselftest.h"
+
+#define	PMD_SIZE		"/sys/kernel/mm/transparent_hugepage/hpage_pmd_size"
+#define	SMAP			"/proc/self/smaps"
+#define	DIRTY_BIT_LOCATION	55
+#define	MAX_LINE_LENGTH		512
+
+uint64_t pagemap_get_entry(int fd, char *start);
+bool pagemap_is_softdirty(int fd, char *start);
+void clear_softdirty(void);
+uint64_t read_pmd_pagesize(void);
+uint64_t check_huge(void *addr);