Add fork test to verify that the MMF_VM_MERGE_ANY flag is inherited by the child process.
Signed-off-by: Stefan Roesch shr@devkernel.io --- tools/testing/selftests/vm/ksm_tests.c | 53 +++++++++++++++++++++++++- 1 file changed, 51 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/vm/ksm_tests.c b/tools/testing/selftests/vm/ksm_tests.c index 9667cb3b8c6a..a0a48ac43b29 100644 --- a/tools/testing/selftests/vm/ksm_tests.c +++ b/tools/testing/selftests/vm/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);