Add fork test to verify that the MMF_VM_MERGE_ANY flag is inherited by
the child process.
Signed-off-by: Stefan Roesch <shr@xxxxxxxxxxxx>
---
tools/testing/selftests/mm/ksm_tests.c | 53 +++++++++++++++++++++++++-
1 file changed, 51 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/mm/ksm_tests.c b/tools/testing/selftests/mm/ksm_tests.c
index 9667cb3b8c6a..a0a48ac43b29 100644
--- a/tools/testing/selftests/mm/ksm_tests.c
+++ b/tools/testing/selftests/mm/ksm_tests.c
@@ -44,6 +44,7 @@ enum ksm_merge_type {
enum ksm_test_name {
CHECK_KSM_MERGE,
+ CHECK_KSM_MERGE_FORK,
CHECK_KSM_UNMERGE,
CHECK_KSM_GET_MERGE_TYPE,
CHECK_KSM_ZERO_PAGE_MERGE,
@@ -126,7 +127,8 @@ static void print_help(void)
" For this test, the size of duplicated memory area (in MiB)\n"
" must be provided using -s option\n"
" -C evaluate the time required to break COW of merged pages.\n"
- " -G query merge mode\n\n");
+ " -G query merge mode\n"
+ " -F evaluate that the KSM process flag is inherited\n\n");
printf(" -a: specify the access protections of pages.\n"
" <prot> must be of the form [rwx].\n"
@@ -325,6 +327,47 @@ static int check_ksm_merge(int merge_type, int mapping, int prot,
return KSFT_FAIL;
}
+/* Verify that prctl ksm flag is inherited. */
+static int check_ksm_fork(void)
+{
+ int rc = KSFT_FAIL;
+ pid_t child_pid;
+
+ if (prctl(PR_SET_MEMORY_MERGE, 1)) {
+ perror("prctl");
+ return KSFT_FAIL;
+ }
+
+ child_pid = fork();
+ if (child_pid == 0) {
+ int is_on = prctl(PR_GET_MEMORY_MERGE, 0);
+
+ if (!is_on)
+ exit(KSFT_FAIL);
+
+ exit(KSFT_PASS);
+ }
+
+ if (child_pid < 0)
+ goto out;
+
+ if (waitpid(child_pid, &rc, 0) < 0)
+ rc = KSFT_FAIL;
+
+ if (prctl(PR_SET_MEMORY_MERGE, 0)) {
+ perror("prctl");
+ rc = KSFT_FAIL;
+ }
+
+out:
+ if (rc == KSFT_PASS)
+ printf("OK\n");
+ else
+ printf("Not OK\n");
+
+ return rc;
+}
+
static int check_ksm_get_merge_type(void)
{
if (prctl(PR_SET_MEMORY_MERGE, 1)) {
@@ -760,7 +803,7 @@ int main(int argc, char *argv[])
bool merge_across_nodes = KSM_MERGE_ACROSS_NODES_DEFAULT;
long size_MB = 0;
- while ((opt = getopt(argc, argv, "ha:p:l:z:m:s:t:GMUZNPCHD")) != -1) {
+ while ((opt = getopt(argc, argv, "ha:p:l:z:m:s:t:FGMUZNPCHD")) != -1) {
switch (opt) {
case 'a':
prot = str_to_prot(optarg);
@@ -811,6 +854,9 @@ int main(int argc, char *argv[])
merge_type = atoi(optarg);
}
break;
+ case 'F':
+ test_name = CHECK_KSM_MERGE_FORK;
+ break;
case 'M':
break;
case 'U':
@@ -867,6 +913,9 @@ int main(int argc, char *argv[])
ret = check_ksm_merge(merge_type, MAP_PRIVATE | MAP_ANONYMOUS, prot, page_count,
ksm_scan_limit_sec, page_size);
break;
+ case CHECK_KSM_MERGE_FORK:
+ ret = check_ksm_fork();
+ break;
case CHECK_KSM_UNMERGE:
ret = check_ksm_unmerge(merge_type, MAP_PRIVATE | MAP_ANONYMOUS, prot,
ksm_scan_limit_sec, page_size);
--
2.30.2
