On 22.05.23 12:54, Yang Yang wrote:
From: xu xin <xu.xin16@xxxxxxxxxx>
Add a function test_unmerge_zero_page() to test the functionality on
unsharing and counting ksm-placed zero pages and counting of this patch
series.
test_unmerge_zero_page() actually contains three subjct test objects:
(1) whether the count of ksm zero pages can update correctly after merging;
(2) whether the count of ksm zero pages can update correctly after
unmerging;
(3) whether ksm zero pages are really unmerged.
Signed-off-by: xu xin <xu.xin16@xxxxxxxxxx>
Cc: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Xuexin Jiang <jiang.xuexin@xxxxxxxxxx>
Reviewed-by: Xiaokai Ran <ran.xiaokai@xxxxxxxxxx>
Reviewed-by: Yang Yang <yang.yang29@xxxxxxxxxx>
---
tools/testing/selftests/mm/ksm_functional_tests.c | 75 +++++++++++++++++++++++
1 file changed, 75 insertions(+)
diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c
index 26853badae70..9b7fb94ed64f 100644
--- a/tools/testing/selftests/mm/ksm_functional_tests.c
+++ b/tools/testing/selftests/mm/ksm_functional_tests.c
@@ -29,6 +29,8 @@
static int ksm_fd;
static int ksm_full_scans_fd;
+static int ksm_zero_pages_fd;
+static int ksm_use_zero_pages_fd;
static int pagemap_fd;
static size_t pagesize;
@@ -59,6 +61,21 @@ static bool range_maps_duplicates(char *addr, unsigned long size)
return false;
}
+static long get_ksm_zero_pages(void)
+{
+ char buf[20];
+ ssize_t read_size;
+ unsigned long ksm_zero_pages;
+
I would add:
if (!ksm_zero_pages_fd)
return 0;
+ read_size = pread(ksm_zero_pages_fd, buf, sizeof(buf) - 1, 0);
+ if (read_size < 0)
+ return -errno;
+ buf[read_size] = 0;
+ ksm_zero_pages = strtol(buf, NULL, 10);
+
+ return ksm_zero_pages;
+}
+
static long ksm_get_full_scans(void)
{
char buf[10];
@@ -159,6 +176,61 @@ static void test_unmerge(void)
munmap(map, size);
}
+static inline unsigned long expected_ksm_pages(unsigned long mergeable_size)
+{
+ return mergeable_size / pagesize;
+}
I suggest to just inline that.
+
+static void test_unmerge_zero_pages(void)
+{
+ const unsigned int size = 2 * MiB;
+ char *map;
+ unsigned long pages_expected;
+
+ ksft_print_msg("[RUN] %s\n", __func__);
+
+ /* Confirm the interfaces*/
Missing space at the end of the comment. But I suggest to just drop this comment.
+ if (ksm_zero_pages_fd < 0) {
+ ksft_test_result_skip("open(\"/sys/kernel/mm/ksm/ksm_zero_pages\") failed\n");
+ return;
+ }
+ if (ksm_use_zero_pages_fd < 0) {
+ 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) {
+ ksft_test_result_skip("write \"/sys/kernel/mm/ksm/use_zero_pages\" failed\n");
+ return;
+ }
+
+ /* Mmap zero pages*/
Missing space at the end of the comment
+ map = mmap_and_merge_range(0x00, size, false);
+ if (map == MAP_FAILED)
+ return;
+
+ /* Check if ksm_zero_pages can be update correctly after merging */
+ pages_expected = expected_ksm_pages(size);
+ ksft_test_result(pages_expected == get_ksm_zero_pages(),
+ "The count zero_page_sharing was updated after merging\n");
+
Make sure that the number of tests (ksft_test_result*() invocations) is on any return
path as expected (e.g., 1).
if (pages_expected != get_ksm_zero_pages) {
ksft_test_result_pass("'zero_page_sharing' updated after merging\n");
goto unmap;
}
+ /* try to unmerge half of the region */
+ if (madvise(map, size / 2, MADV_UNMERGEABLE)) {
+ ksft_test_result_fail("MADV_UNMERGEABLE failed\n");
+ goto unmap;
+ }
+
+ /* Check if ksm_zero_pages can be update correctly after unmerging */
+ pages_expected = expected_ksm_pages(size / 2);
Just do
pages_expected /= 2;
+ ksft_test_result(pages_expected == get_ksm_zero_pages(),
+ "The count zero_page_sharing was updated after unmerging\n");
+
if (pages_expected == get_ksm_zero_pages()) {
ksft_test_result_pass("'zero_page_sharing' updated after unmerging\n");
goto unmap;
}
+ /* Check if ksm zero pages are really unmerged */
+ ksft_test_result(!range_maps_duplicates(map, size / 2),
+ "KSM zero pages were unmerged\n");
+unmap:
+ munmap(map, size);
+}
+
static void test_unmerge_discarded(void)
{
const unsigned int size = 2 * MiB;
@@ -379,8 +451,11 @@ int main(int argc, char **argv)
pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
if (pagemap_fd < 0)
ksft_exit_skip("open(\"/proc/self/pagemap\") failed\n");
+ ksm_zero_pages_fd = open("/sys/kernel/mm/ksm/ksm_zero_pages", O_RDONLY);
+ ksm_use_zero_pages_fd = open("/sys/kernel/mm/ksm/use_zero_pages", O_RDWR);
test_unmerge();
+ test_unmerge_zero_pages();
test_unmerge_discarded();
#ifdef __NR_userfaultfd
test_unmerge_uffd_wp();
You should need something like this:
diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c
index 26853badae70..00df05bfc3a3 100644
--- a/tools/testing/selftests/mm/ksm_functional_tests.c
+++ b/tools/testing/selftests/mm/ksm_functional_tests.c
@@ -358,7 +358,7 @@ static void test_prctl_unmerge(void)
int main(int argc, char **argv)
{
- unsigned int tests = 5;
+ unsigned int tests = 6;
int err;
#ifdef __NR_userfaultfd
--
Thanks,
David / dhildenb
