Setting the path for subsystems visible via -XshowSettings (Metrics.java/SubSystem.java) is out-of-sync with the logic in Hotspot's osContainer_linux.cpp

Around line 87 in osContainer_linux.cpp function set_subsystem_path() has this:

          if (strcmp(cgroup_path,"/") != 0) {
            buflen = strlen(buf);
            if ((buflen + strlen(cgroup_path)) > (MAXPATHLEN-1)) {
              return;
            }
            strncat(buf, cgroup_path, MAXPATHLEN-buflen);
            buf[MAXPATHLEN-1] = '\0';
          }
          _path = os::strdup(buf);

The same piece of code in SubSystem.java method setPath has:

                if (cgroupPath.equals("/")) {
                    path = mountPoint + cgroupPath;
                }
                else {
                    path = mountPoint;
                }

So the native code uses "'/' != cgroupPath" while the Java code has "'/' == cgroupPath".

This is an issue for implementing Metrics.java bits for JDK-8217338