[cgroups v1] Metric limits not properly detected on some join controller combinations

This bug is similar to JDK-8217766. In fact, it had an incomplete fix for the Metrics (Java) side.

On a system with join controllers, /proc/self/cgroup, might look like this:

9:pids:/user.slice/user-1000.slice/session-2.scope
8:perf_event:/
7:blkio:/user.slice
6:rdma:/
5:cpuset:/
4:devices:/user.slice
3:cpu,cpuacct,memory,net_cls,net_prio,hugetlb:/user.slice/user-1000.slice/session-2.scope
2:freezer:/
1:name=systemd:/user.slice/user-1000.slice/session-2.scope
0::/user.slice/user-1000.slice/session-2.scope

Then, the Java code to set the path to for the controller reads:

        try (Stream<String> lines =
                CgroupUtil.readFilePrivileged(Paths.get("/proc/self/cgroup"))) {

            lines.map(line -> line.split(":"))
                 .filter(line -> (line.length >= 3))
                 .forEach(line -> setSubSystemControllerPath(subsystem, line));

        } catch (IOException e) {
            return null;
        }


where setSubSystemController() reads:

/**
     * setSubSystemPath based on the contents of /proc/self/cgroup
     */
    private static void setSubSystemControllerPath(CgroupV1Subsystem subsystem, String[] entry) {
        String controllerName;
        String base;
        CgroupV1SubsystemController controller = null;
        CgroupV1SubsystemController controller2 = null;

        controllerName = entry[1];
        base = entry[2];
        if (controllerName != null && base != null) {
            switch (controllerName) {
                case "memory":
                    controller = subsystem.memoryController();
                    break;
                case "cpuset":
                    controller = subsystem.cpuSetController();
                    break;
                case "cpu,cpuacct":
                case "cpuacct,cpu":
                    controller = subsystem.cpuController();
                    controller2 = subsystem.cpuAcctController();
                    break;
                case "cpuacct":
                    controller = subsystem.cpuAcctController();
                    break;
                case "cpu":
                    controller = subsystem.cpuController();
                    break;
                case "blkio":
                    controller = subsystem.blkIOController();
                    break;
                // Ignore subsystems that we don't support
                default:
                    break;
            }
        }

        if (controller != null) {
            controller.setPath(base);
            if (controller instanceof CgroupV1MemorySubSystemController) {
                CgroupV1MemorySubSystemController memorySubSystem = (CgroupV1MemorySubSystemController)controller;
                boolean isHierarchial = getHierarchical(memorySubSystem);
                memorySubSystem.setHierarchical(isHierarchial);
                boolean isSwapEnabled = getSwapEnabled(memorySubSystem);
                memorySubSystem.setSwapEnabled(isSwapEnabled);
            }
        if (controller != null) {
            controller.setPath(base);
            if (controller instanceof CgroupV1MemorySubSystemController) {
                CgroupV1MemorySubSystemController memorySubSystem = (CgroupV1MemorySubSystemController)controller;
                boolean isHierarchial = getHierarchical(memorySubSystem);
                memorySubSystem.setHierarchical(isHierarchial);
                boolean isSwapEnabled = getSwapEnabled(memorySubSystem);
                memorySubSystem.setSwapEnabled(isSwapEnabled);
            }
            subsystem.setActiveSubSystems();
        }
        if (controller2 != null) {
            controller2.setPath(base);
        }

So for the example /proc/self/cgroup file it only sets the path for "blkio" and "cpuset". Others are not correctly set because they are on a joined path.

The net effect of this is that Metrics doesn't report the container limits correctly on such systems.