test_mknod
test_mknod("/dev/test_dev_cgroup_zero", S_IFCHR, 1, 5, -1,
test_mknod("/dev/test_dev_cgroup_block", S_IFBLK, 1, 3, -1,
test_mknod("/dev/test_dev_cgroup_null", S_IFCHR, 1, 3, 0, 0);