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selftest/mm: ksm_functional_tests: extend test case for ksm fork/exec

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This extends test_prctl_fork() and test_prctl_fork_exec() to make sure
that deduplication really happens, instead of only testing the
MMF_VM_MERGE_ANY flag is set.

[colin.i.king@gmail.com: fix spelling mistake in ksft_test_result_skip message]
  Link: https://lkml.kernel.org/r/20240402081537.1365939-1-colin.i.king@gmail.com
Link: https://lkml.kernel.org/r/20240328111010.1502191-4-tujinjiang@huawei.com
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Stefan Roesch <shr@devkernel.io>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Jinjiang Tu 2024-03-28 19:10:10 +08:00 committed by Andrew Morton
parent 7abaacb8e5
commit 6c47de3be3
1 changed files with 38 additions and 11 deletions
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49
tools/testing/selftests/mm/ksm_functional_tests.c
View file

@ -475,6 +475,36 @@ static void test_prctl(void)
ksft_test_result_pass("Setting/clearing PR_SET_MEMORY_MERGE works\n");
}
static int test_child_ksm(void)
{
const unsigned int size = 2 * MiB;
char *map;
/* Test if KSM is enabled for the process. */
if (prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0) != 1)
return -1;
/* Test if merge could really happen. */
map = __mmap_and_merge_range(0xcf, size, PROT_READ | PROT_WRITE, KSM_MERGE_NONE);
if (map == MAP_MERGE_FAIL)
return -2;
else if (map == MAP_MERGE_SKIP)
return -3;
munmap(map, size);
return 0;
}
static void test_child_ksm_err(int status)
{
if (status == -1)
ksft_test_result_fail("unexpected PR_GET_MEMORY_MERGE result in child\n");
else if (status == -2)
ksft_test_result_fail("Merge in child failed\n");
else if (status == -3)
ksft_test_result_skip("Merge in child skipped\n");
}
/* Verify that prctl ksm flag is inherited. */
static void test_prctl_fork(void)
{
@ -494,7 +524,7 @@ static void test_prctl_fork(void)
child_pid = fork();
if (!child_pid) {
exit(prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0));
exit(test_child_ksm());
} else if (child_pid < 0) {
ksft_test_result_fail("fork() failed\n");
return;
@ -503,8 +533,11 @@ static void test_prctl_fork(void)
if (waitpid(child_pid, &status, 0) < 0) {
ksft_test_result_fail("waitpid() failed\n");
return;
} else if (WEXITSTATUS(status) != 1) {
ksft_test_result_fail("unexpected PR_GET_MEMORY_MERGE result in child\n");
}
status = WEXITSTATUS(status);
if (status) {
test_child_ksm_err(status);
return;
}
@ -516,12 +549,6 @@ static void test_prctl_fork(void)
ksft_test_result_pass("PR_SET_MEMORY_MERGE value is inherited\n");
}
static int ksm_fork_exec_child(void)
{
/* Test if KSM is enabled for the process. */
return prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0) == 1;
}
static void test_prctl_fork_exec(void)
{
int ret, status;
@ -554,7 +581,7 @@ static void test_prctl_fork_exec(void)
if (WIFEXITED(status)) {
status = WEXITSTATUS(status);
if (status) {
ksft_test_result_fail("KSM not enabled\n");
test_child_ksm_err(status);
return;
}
} else {
@ -635,7 +662,7 @@ int main(int argc, char **argv)
int err;
if (argc > 1 && !strcmp(argv[1], FORK_EXEC_CHILD_PRG_NAME)) {
exit(ksm_fork_exec_child() == 1 ? 0 : 1);
exit(test_child_ksm());
}
#ifdef __NR_userfaultfd