selftests: cgroup/memcontrol: add basic test for swap controls

The new test verifies that memory.swap.max and memory.swap.current behave
as expected for simple allocation scenarios

Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
index a938b6c8b55a..41cc3b5e5be1 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.c
+++ b/tools/testing/selftests/cgroup/cgroup_util.c
@@ -315,3 +315,19 @@ int alloc_anon(const char *cgroup, void *arg)
 	free(buf);
 	return 0;
 }
+
+int is_swap_enabled(void)
+{
+	char buf[PAGE_SIZE];
+	const char delim[] = "\n";
+	int cnt = 0;
+	char *line;
+
+	if (read_text("/proc/swaps", buf, sizeof(buf)) <= 0)
+		return -1;
+
+	for (line = strtok(buf, delim); line; line = strtok(NULL, delim))
+		cnt++;
+
+	return cnt > 1;
+}