Add a dedicated test at the end of main() that stages memcg_path via sysfs and verifies its readback. Configure the memcg filter before start(), do not call commit(), and ignore start() failures so the test does not depend on CONFIG_MEMCG or cgroup layout. Call stop() for cleanup without checking its return value. Link: https://lore.kernel.org/D2B37130D38E09AC+20260601090634.241864-1-niecheng1@uniontech.com Link: https://lore.kernel.org/20260629144812.134159-3-sj@kernel.org Signed-off-by: Cheng Nie <niecheng1@uniontech.com> Signed-off-by: SJ Park <sj@kernel.org> Reviewed-by: SJ Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>