[RFC Patch 1/2] selftests/mm: put general ksm operation into vm_util

[Wei Yang <richard.weiyang@gmail.com>]

There are some general ksm operations could be used by other related
test case. Put them into vm_util for common use.

This is a preparation patch for later use.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Harry Yoo <harry.yoo@oracle.com>
---
 .../selftests/mm/ksm_functional_tests.c       | 76 +++----------------
 tools/testing/selftests/mm/vm_util.c          | 71 +++++++++++++++++
 tools/testing/selftests/mm/vm_util.h          |  7 ++
 3 files changed, 88 insertions(+), 66 deletions(-)

diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c
index b61803e36d1c..9fb79f6bf86d 100644
--- a/tools/testing/selftests/mm/ksm_functional_tests.c
+++ b/tools/testing/selftests/mm/ksm_functional_tests.c
@@ -73,74 +73,18 @@ static bool range_maps_duplicates(char *addr, unsigned long size)
 	return false;
 }
 
-static long get_my_ksm_zero_pages(void)
-{
-	char buf[200];
-	char *substr_ksm_zero;
-	size_t value_pos;
-	ssize_t read_size;
-	unsigned long my_ksm_zero_pages;
-
-	if (!proc_self_ksm_stat_fd)
-		return 0;
-
-	read_size = pread(proc_self_ksm_stat_fd, buf, sizeof(buf) - 1, 0);
-	if (read_size < 0)
-		return -errno;
-
-	buf[read_size] = 0;
-
-	substr_ksm_zero = strstr(buf, "ksm_zero_pages");
-	if (!substr_ksm_zero)
-		return 0;
-
-	value_pos = strcspn(substr_ksm_zero, "0123456789");
-	my_ksm_zero_pages = strtol(substr_ksm_zero + value_pos, NULL, 10);
-
-	return my_ksm_zero_pages;
-}
-
-static long get_my_merging_pages(void)
-{
-	char buf[10];
-	ssize_t ret;
-
-	if (proc_self_ksm_merging_pages_fd < 0)
-		return proc_self_ksm_merging_pages_fd;
-
-	ret = pread(proc_self_ksm_merging_pages_fd, buf, sizeof(buf) - 1, 0);
-	if (ret <= 0)
-		return -errno;
-	buf[ret] = 0;
-
-	return strtol(buf, NULL, 10);
-}
-
-static long ksm_get_full_scans(void)
-{
-	char buf[10];
-	ssize_t ret;
-
-	ret = pread(ksm_full_scans_fd, buf, sizeof(buf) - 1, 0);
-	if (ret <= 0)
-		return -errno;
-	buf[ret] = 0;
-
-	return strtol(buf, NULL, 10);
-}
-
 static int ksm_merge(void)
 {
 	long start_scans, end_scans;
 
 	/* Wait for two full scans such that any possible merging happened. */
-	start_scans = ksm_get_full_scans();
+	start_scans = ksm_get_full_scans(ksm_full_scans_fd);
 	if (start_scans < 0)
 		return start_scans;
-	if (write(ksm_fd, "1", 1) != 1)
+	if (ksm_start_and_merge(ksm_fd) != 1)
 		return -errno;
 	do {
-		end_scans = ksm_get_full_scans();
+		end_scans = ksm_get_full_scans(ksm_full_scans_fd);
 		if (end_scans < 0)
 			return end_scans;
 	} while (end_scans < start_scans + 2);
@@ -150,7 +94,7 @@ static int ksm_merge(void)
 
 static int ksm_unmerge(void)
 {
-	if (write(ksm_fd, "2", 1) != 1)
+	if (ksm_stop_and_unmerge(ksm_fd) != 1)
 		return -errno;
 	return 0;
 }
@@ -168,7 +112,7 @@ static char *__mmap_and_merge_range(char val, unsigned long size, int prot,
 		return err_map;
 	}
 
-	if (get_my_merging_pages() > 0) {
+	if (ksm_get_self_merging_pages(proc_self_ksm_merging_pages_fd) > 0) {
 		ksft_print_msg("Still pages merged\n");
 		return err_map;
 	}
@@ -227,7 +171,7 @@ static char *__mmap_and_merge_range(char val, unsigned long size, int prot,
 	 * Check if anything was merged at all. Ignore the zero page that is
 	 * accounted differently (depending on kernel support).
 	 */
-	if (val && !get_my_merging_pages()) {
+	if (val && !ksm_get_self_merging_pages(proc_self_ksm_merging_pages_fd)) {
 		ksft_print_msg("No pages got merged\n");
 		goto unmap;
 	}
@@ -294,7 +238,7 @@ static void test_unmerge_zero_pages(void)
 		ksft_test_result_skip("open \"/sys/kernel/mm/ksm/use_zero_pages\" failed\n");
 		return;
 	}
-	if (write(ksm_use_zero_pages_fd, "1", 1) != 1) {
+	if (ksm_use_zero_pages(ksm_use_zero_pages_fd) != 1) {
 		ksft_test_result_skip("write \"/sys/kernel/mm/ksm/use_zero_pages\" failed\n");
 		return;
 	}
@@ -306,7 +250,7 @@ static void test_unmerge_zero_pages(void)
 
 	/* Check if ksm_zero_pages is updated correctly after KSM merging */
 	pages_expected = size / pagesize;
-	if (pages_expected != get_my_ksm_zero_pages()) {
+	if (pages_expected != ksm_get_self_zero_pages(proc_self_ksm_stat_fd)) {
 		ksft_test_result_fail("'ksm_zero_pages' updated after merging\n");
 		goto unmap;
 	}
@@ -319,7 +263,7 @@ static void test_unmerge_zero_pages(void)
 
 	/* Check if ksm_zero_pages is updated correctly after unmerging */
 	pages_expected /= 2;
-	if (pages_expected != get_my_ksm_zero_pages()) {
+	if (pages_expected != ksm_get_self_zero_pages(proc_self_ksm_stat_fd)) {
 		ksft_test_result_fail("'ksm_zero_pages' updated after unmerging\n");
 		goto unmap;
 	}
@@ -329,7 +273,7 @@ static void test_unmerge_zero_pages(void)
 		*((unsigned int *)&map[offs]) = offs;
 
 	/* Now we should have no zeropages remaining. */
-	if (get_my_ksm_zero_pages()) {
+	if (ksm_get_self_zero_pages(proc_self_ksm_stat_fd)) {
 		ksft_test_result_fail("'ksm_zero_pages' updated after write fault\n");
 		goto unmap;
 	}
diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
index 1357e2d6a7b6..115422e9eb68 100644
--- a/tools/testing/selftests/mm/vm_util.c
+++ b/tools/testing/selftests/mm/vm_util.c
@@ -486,3 +486,74 @@ int close_procmap(struct procmap_fd *procmap)
 {
 	return close(procmap->fd);
 }
+
+int ksm_use_zero_pages(int ksm_use_zero_pages_fd)
+{
+	return write(ksm_use_zero_pages_fd, "1", 1);
+}
+
+int ksm_start_and_merge(int ksm_fd)
+{
+	return write(ksm_fd, "1", 1);
+}
+
+int ksm_stop_and_unmerge(int ksm_fd)
+{
+	return write(ksm_fd, "2", 1);
+}
+
+long ksm_get_full_scans(int ksm_full_scans_fd)
+{
+	char buf[10];
+	ssize_t ret;
+
+	ret = pread(ksm_full_scans_fd, buf, sizeof(buf) - 1, 0);
+	if (ret <= 0)
+		return -errno;
+	buf[ret] = 0;
+
+	return strtol(buf, NULL, 10);
+}
+
+long ksm_get_self_merging_pages(int proc_self_ksm_merging_pages_fd)
+{
+	char buf[10];
+	ssize_t ret;
+
+	if (proc_self_ksm_merging_pages_fd < 0)
+		return proc_self_ksm_merging_pages_fd;
+
+	ret = pread(proc_self_ksm_merging_pages_fd, buf, sizeof(buf) - 1, 0);
+	if (ret <= 0)
+		return -errno;
+	buf[ret] = 0;
+
+	return strtol(buf, NULL, 10);
+}
+
+long ksm_get_self_zero_pages(int proc_self_ksm_stat_fd)
+{
+	char buf[200];
+	char *substr_ksm_zero;
+	size_t value_pos;
+	ssize_t read_size;
+	unsigned long my_ksm_zero_pages;
+
+	if (!proc_self_ksm_stat_fd)
+		return 0;
+
+	read_size = pread(proc_self_ksm_stat_fd, buf, sizeof(buf) - 1, 0);
+	if (read_size < 0)
+		return -errno;
+
+	buf[read_size] = 0;
+
+	substr_ksm_zero = strstr(buf, "ksm_zero_pages");
+	if (!substr_ksm_zero)
+		return 0;
+
+	value_pos = strcspn(substr_ksm_zero, "0123456789");
+	my_ksm_zero_pages = strtol(substr_ksm_zero + value_pos, NULL, 10);
+
+	return my_ksm_zero_pages;
+}
diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h
index 9211ba640d9c..99c1b1aa1813 100644
--- a/tools/testing/selftests/mm/vm_util.h
+++ b/tools/testing/selftests/mm/vm_util.h
@@ -95,6 +95,13 @@ static inline int open_self_procmap(struct procmap_fd *procmap_out)
 	return open_procmap(pid, procmap_out);
 }
 
+int ksm_use_zero_pages(int ksm_use_zero_pages_fd);
+int ksm_start_and_merge(int ksm_fd);
+int ksm_stop_and_unmerge(int ksm_fd);
+long ksm_get_full_scans(int ksm_full_scans_fd);
+long ksm_get_self_merging_pages(int proc_self_ksm_merging_pages_fd);
+long ksm_get_self_zero_pages(int proc_self_ksm_stat_fd);
+
 /*
  * On ppc64 this will only work with radix 2M hugepage size
  */
-- 
2.34.1