[PATCH 2/3] kselftest/cgroup: fix unexcepted testing failure on test_core

From: Alex Shi
Date: Wed May 15 2019 - 05:09:36 EST

The cgroup testing relys on the root cgroup's subtree_control setting,
If the 'memory' controller isn't set, some test cases will be failed
as following:

$sudo ./test_core
not ok 1 test_cgcore_internal_process_constraint
ok 2 test_cgcore_top_down_constraint_enable
not ok 3 test_cgcore_top_down_constraint_disable

To correct this unexcepted failure, this patch write the 'memory' to
subtree_control of root to get a right result.

Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Claudio Zumbo <claudioz@xxxxxx>
Cc: Claudio <claudiozumbo@xxxxxxxxx>
Cc: linux-kselftest@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
tools/testing/selftests/cgroup/test_core.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/tools/testing/selftests/cgroup/test_core.c b/tools/testing/selftests/cgroup/test_core.c
index be59f9c34ea2..b1a570d7c557 100644
--- a/tools/testing/selftests/cgroup/test_core.c
+++ b/tools/testing/selftests/cgroup/test_core.c
@@ -376,6 +376,11 @@ int main(int argc, char *argv[])

if (cg_find_unified_root(root, sizeof(root)))
ksft_exit_skip("cgroup v2 isn't mounted\n");
+ if (cg_read_strstr(root, "cgroup.subtree_control", "memory"))
+ if (cg_write(root, "cgroup.subtree_control", "+memory"))
+ ksft_exit_skip("Failed to set root memory controller\n");
for (i = 0; i < ARRAY_SIZE(tests); i++) {
switch (tests[i].fn(root)) {