Question: How to limit devices in cgroup v2

[yipengyin]

I found no device subsystem in cgroup v2. How to limit devices in cgroup v2. Thank you!

impl Hierarchy for V2 {
    fn v2(&self) -> bool {
        true
    }

    fn subsystems(&self) -> Vec<Subsystem> {
        let p = format!("{}/{}", UNIFIED_MOUNTPOINT, "cgroup.controllers");
        let ret = fs::read_to_string(p.as_str());
        if ret.is_err() {
            return vec![];
        }

        let mut subs = vec![];

        let controllers = ret.unwrap().trim().to_string();
        let mut controller_list: Vec<&str> = controllers.split(' ').collect();

        // The freezer functionality is present in V2, but not as a controller,
        // but apparently as a core functionality. FreezerController supports
        // that, but we must explicitly fake the controller here.
        controller_list.push("freezer");

        for s in controller_list {
            match s {
                "cpu" => {
                    subs.push(Subsystem::Cpu(CpuController::new(self.root(), true)));
                }
                "io" => {
                    subs.push(Subsystem::BlkIo(BlkIoController::new(self.root(), true)));
                }
                "cpuset" => {
                    subs.push(Subsystem::CpuSet(CpuSetController::new(self.root(), true)));
                }
                "memory" => {
                    subs.push(Subsystem::Mem(MemController::new(self.root(), true)));
                }
                "pids" => {
                    subs.push(Subsystem::Pid(PidController::new(self.root(), true)));
                }
                "freezer" => {
                    subs.push(Subsystem::Freezer(FreezerController::new(
                        self.root(),
                        true,
                    )));
                }
                "hugetlb" => {
                    subs.push(Subsystem::HugeTlb(HugeTlbController::new(
                        self.root(),
                        true,
                    )));
                }
                _ => {}
            }
        }

        subs
    }
}