diff --git a/Cargo.toml b/Cargo.toml
index 524e006..156a69f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,7 +11,9 @@ edition = "2018"
 
 [dependencies]
 log = "0.4"
+regex = "1.1"
+nix = "0.18.0"
+libc = "0.2"
 
 [dev-dependencies]
-nix = "0.11.0"
-libc = "0.2.43"
+libc = "0.2.76"
diff --git a/src/blkio.rs b/src/blkio.rs
index 5e4cf3d..153a68e 100644
--- a/src/blkio.rs
+++ b/src/blkio.rs
@@ -1,4 +1,5 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 And Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
@@ -11,8 +12,8 @@ use std::fs::File;
 use std::io::{Read, Write};
 use std::path::PathBuf;
 
-use crate::error::*;
 use crate::error::ErrorKind::*;
+use crate::error::*;
 
 use crate::{
     BlkIoResources, ControllIdentifier, ControllerInternal, Controllers, Resources, Subsystem,
@@ -26,6 +27,7 @@ use crate::{
 pub struct BlkIoController {
     base: PathBuf,
     path: PathBuf,
+    v2: bool,
 }
 
 #[derive(Eq, PartialEq, Debug)]
@@ -58,6 +60,28 @@ pub struct IoService {
     pub total: u64,
 }
 
+#[derive(Eq, PartialEq, Debug)]
+/// Per-device activity from the control group.
+/// Only for cgroup v2
+pub struct IoStat {
+    /// The major number of the device.
+    pub major: i16,
+    /// The minor number of the device.
+    pub minor: i16,
+    /// How many bytes were read from the device.
+    pub rbytes: u64,
+    /// How many bytes were written to the device.
+    pub wbytes: u64,
+    /// How many iops were read from the device.
+    pub rios: u64,
+    /// How many iops were written to the device.
+    pub wios: u64,
+    /// How many discard bytes were read from the device.
+    pub dbytes: u64,
+    /// How many discard iops were written to the device.
+    pub dios: u64,
+}
+
 fn parse_io_service(s: String) -> Result<Vec<IoService>> {
     s.lines()
         .filter(|x| x.split_whitespace().collect::<Vec<_>>().len() == 3)
@@ -99,6 +123,41 @@ fn parse_io_service(s: String) -> Result<Vec<IoService>> {
         })
 }
 
+fn get_value(s: &str) -> String {
+    let arr = s.split(':').collect::<Vec<&str>>();
+    if arr.len() != 2 {
+        return "0".to_string();
+    }
+    arr[1].to_string()
+}
+
+fn parse_io_stat(s: String) -> Result<Vec<IoStat>> {
+    // line:
+    // 8:0 rbytes=180224 wbytes=0 rios=3 wios=0 dbytes=0 dios=0
+    let v = s
+        .lines()
+        .filter(|x| x.split_whitespace().collect::<Vec<_>>().len() == 7)
+        .map(|x| {
+            let arr = x.split_whitespace().collect::<Vec<&str>>();
+            let device = arr[0].split(":").collect::<Vec<&str>>();
+            let (major, minor) = (device[0], device[1]);
+
+            IoStat {
+                major: major.parse::<i16>().unwrap(),
+                minor: minor.parse::<i16>().unwrap(),
+                rbytes: get_value(arr[1]).parse::<u64>().unwrap(),
+                wbytes: get_value(arr[2]).parse::<u64>().unwrap(),
+                rios: get_value(arr[3]).parse::<u64>().unwrap(),
+                wios: get_value(arr[4]).parse::<u64>().unwrap(),
+                dbytes: get_value(arr[5]).parse::<u64>().unwrap(),
+                dios: get_value(arr[6]).parse::<u64>().unwrap(),
+            }
+        })
+        .collect::<Vec<IoStat>>();
+
+    Ok(v)
+}
+
 fn parse_io_service_total(s: String) -> Result<u64> {
     s.lines()
         .filter(|x| x.split_whitespace().collect::<Vec<_>>().len() == 2)
@@ -146,7 +205,7 @@ fn parse_blkio_data(s: String) -> Result<Vec<BlkIoData>> {
 
 /// Current state and statistics about how throttled are the block devices when accessed from the
 /// controller's control group.
-#[derive(Debug)]
+#[derive(Default, Debug)]
 pub struct BlkIoThrottle {
     /// Statistics about the bytes transferred between the block devices by the tasks in this
     /// control group.
@@ -181,7 +240,7 @@ pub struct BlkIoThrottle {
 }
 
 /// Statistics and state of the block devices.
-#[derive(Debug)]
+#[derive(Default, Debug)]
 pub struct BlkIo {
     /// The number of BIOS requests merged into I/O requests by the control group's tasks.
     pub io_merged: Vec<IoService>,
@@ -258,6 +317,9 @@ pub struct BlkIo {
     pub weight: u64,
     /// Same as `weight`, but per-block-device.
     pub weight_device: Vec<BlkIoData>,
+
+    /// IoStat for cgroup v2
+    pub io_stat: Vec<IoStat>,
 }
 
 impl ControllerInternal for BlkIoController {
@@ -274,17 +336,30 @@ impl ControllerInternal for BlkIoController {
         &self.base
     }
 
+    fn is_v2(&self) -> bool {
+        self.v2
+    }
+
     fn apply(&self, res: &Resources) -> Result<()> {
         // get the resources that apply to this controller
         let res: &BlkIoResources = &res.blkio;
 
         if res.update_values {
-            let _ = self.set_weight(res.weight as u64);
-            let _ = self.set_leaf_weight(res.leaf_weight as u64);
+            if let Some(weight) = res.weight {
+                let _ = self.set_weight(weight as u64);
+            }
+            if let Some(leaf_weight) = res.leaf_weight {
+                let _ = self.set_leaf_weight(leaf_weight as u64);
+            }
 
             for dev in &res.weight_device {
-                let _ = self.set_weight_for_device(dev.major, dev.minor, dev.weight as u64);
-                let _ = self.set_leaf_weight_for_device(dev.major, dev.minor, dev.leaf_weight as u64);
+                if let Some(weight) = dev.weight {
+                    let _ = self.set_weight_for_device(dev.major, dev.minor, weight as u64);
+                }
+                if let Some(leaf_weight) = dev.leaf_weight {
+                    let _ =
+                        self.set_leaf_weight_for_device(dev.major, dev.minor, leaf_weight as u64);
+                }
             }
 
             for dev in &res.throttle_read_bps_device {
@@ -339,25 +414,45 @@ fn read_string_from(mut file: File) -> Result<String> {
 fn read_u64_from(mut file: File) -> Result<u64> {
     let mut string = String::new();
     match file.read_to_string(&mut string) {
-        Ok(_) => string.trim().parse().map_err(|e| Error::with_cause(ParseError, e)),
+        Ok(_) => string
+            .trim()
+            .parse()
+            .map_err(|e| Error::with_cause(ParseError, e)),
         Err(e) => Err(Error::with_cause(ReadFailed, e)),
     }
 }
 
 impl BlkIoController {
     /// Constructs a new `BlkIoController` with `oroot` serving as the root of the control group.
-    pub fn new(oroot: PathBuf) -> Self {
+    pub fn new(oroot: PathBuf, v2: bool) -> Self {
         let mut root = oroot;
-        root.push(Self::controller_type().to_string());
+        if !v2 {
+            root.push(Self::controller_type().to_string());
+        }
         Self {
             base: root.clone(),
             path: root,
+            v2: v2,
         }
     }
 
+    fn blkio_v2(&self) -> BlkIo {
+        let mut blkio: BlkIo = Default::default();
+        blkio.io_stat = self
+            .open_path("io.stat", false)
+            .and_then(read_string_from)
+            .and_then(parse_io_stat)
+            .unwrap_or(Vec::new());
+
+        blkio
+    }
+
     /// Gathers statistics about and reports the state of the block devices used by the control
     /// group's tasks.
     pub fn blkio(&self) -> BlkIo {
+        if self.v2 {
+            return self.blkio_v2();
+        }
         BlkIo {
             io_merged: self
                 .open_path("blkio.io_merged", false)
@@ -579,6 +674,7 @@ impl BlkIoController {
                 .and_then(read_string_from)
                 .and_then(parse_blkio_data)
                 .unwrap_or(Vec::new()),
+            io_stat: Vec::new(),
         }
     }
 
@@ -593,12 +689,7 @@ impl BlkIoController {
     }
 
     /// Same as `set_leaf_weight()`, but settable per each block device.
-    pub fn set_leaf_weight_for_device(
-        &self,
-        major: u64,
-        minor: u64,
-        weight: u64,
-    ) -> Result<()> {
+    pub fn set_leaf_weight_for_device(&self, major: u64, minor: u64, weight: u64) -> Result<()> {
         self.open_path("blkio.leaf_weight_device", true)
             .and_then(|mut file| {
                 file.write_all(format!("{}:{} {}", major, minor, weight).as_ref())
@@ -617,84 +708,89 @@ impl BlkIoController {
 
     /// Throttle the bytes per second rate of read operation affecting the block device
     /// `major:minor` to `bps`.
-    pub fn throttle_read_bps_for_device(
-        &self,
-        major: u64,
-        minor: u64,
-        bps: u64,
-    ) -> Result<()> {
-        self.open_path("blkio.throttle.read_bps_device", true)
-            .and_then(|mut file| {
-                file.write_all(format!("{}:{} {}", major, minor, bps).to_string().as_ref())
-                    .map_err(|e| Error::with_cause(WriteFailed, e))
-            })
+    pub fn throttle_read_bps_for_device(&self, major: u64, minor: u64, bps: u64) -> Result<()> {
+        let mut file = "blkio.throttle.read_bps_device";
+        let mut content = format!("{}:{} {}", major, minor, bps);
+        if self.v2 {
+            file = "io.max";
+            content = format!("{}:{} rbps={}", major, minor, bps);
+        }
+        self.open_path(file, true).and_then(|mut file| {
+            file.write_all(content.as_ref())
+                .map_err(|e| Error::with_cause(WriteFailed, e))
+        })
     }
 
     /// Throttle the I/O operations per second rate of read operation affecting the block device
     /// `major:minor` to `bps`.
-    pub fn throttle_read_iops_for_device(
-        &self,
-        major: u64,
-        minor: u64,
-        iops: u64,
-    ) -> Result<()> {
-        self.open_path("blkio.throttle.read_iops_device", true)
-            .and_then(|mut file| {
-                file.write_all(format!("{}:{} {}", major, minor, iops).to_string().as_ref())
-                    .map_err(|e| Error::with_cause(WriteFailed, e))
-            })
+    pub fn throttle_read_iops_for_device(&self, major: u64, minor: u64, iops: u64) -> Result<()> {
+        let mut file = "blkio.throttle.read_iops_device";
+        let mut content = format!("{}:{} {}", major, minor, iops);
+        if self.v2 {
+            file = "io.max";
+            content = format!("{}:{} riops={}", major, minor, iops);
+        }
+        self.open_path(file, true).and_then(|mut file| {
+            file.write_all(content.as_ref())
+                .map_err(|e| Error::with_cause(WriteFailed, e))
+        })
     }
     /// Throttle the bytes per second rate of write operation affecting the block device
     /// `major:minor` to `bps`.
-    pub fn throttle_write_bps_for_device(
-        &self,
-        major: u64,
-        minor: u64,
-        bps: u64,
-    ) -> Result<()> {
-        self.open_path("blkio.throttle.write_bps_device", true)
-            .and_then(|mut file| {
-                file.write_all(format!("{}:{} {}", major, minor, bps).to_string().as_ref())
-                    .map_err(|e| Error::with_cause(WriteFailed, e))
-            })
+    pub fn throttle_write_bps_for_device(&self, major: u64, minor: u64, bps: u64) -> Result<()> {
+        let mut file = "blkio.throttle.write_bps_device";
+        let mut content = format!("{}:{} {}", major, minor, bps);
+        if self.v2 {
+            file = "io.max";
+            content = format!("{}:{} wbps={}", major, minor, bps);
+        }
+        self.open_path(file, true).and_then(|mut file| {
+            file.write_all(content.as_ref())
+                .map_err(|e| Error::with_cause(WriteFailed, e))
+        })
     }
 
     /// Throttle the I/O operations per second rate of write operation affecting the block device
     /// `major:minor` to `bps`.
-    pub fn throttle_write_iops_for_device(
-        &self,
-        major: u64,
-        minor: u64,
-        iops: u64,
-    ) -> Result<()> {
-        self.open_path("blkio.throttle.write_iops_device", true)
-            .and_then(|mut file| {
-                file.write_all(format!("{}:{} {}", major, minor, iops).to_string().as_ref())
-                    .map_err(|e| Error::with_cause(WriteFailed, e))
-            })
+    pub fn throttle_write_iops_for_device(&self, major: u64, minor: u64, iops: u64) -> Result<()> {
+        let mut file = "blkio.throttle.write_iops_device";
+        let mut content = format!("{}:{} {}", major, minor, iops);
+        if self.v2 {
+            file = "io.max";
+            content = format!("{}:{} wiops={}", major, minor, iops);
+        }
+        self.open_path(file, true).and_then(|mut file| {
+            file.write_all(content.as_ref())
+                .map_err(|e| Error::with_cause(WriteFailed, e))
+        })
     }
 
     /// Set the weight of the control group's tasks.
     pub fn set_weight(&self, w: u64) -> Result<()> {
-        self.open_path("blkio.weight", true)
-            .and_then(|mut file| {
-                file.write_all(w.to_string().as_ref())
-                    .map_err(|e| Error::with_cause(WriteFailed, e))
-            })
+        // Attation: may not find in high kernel version.
+        let mut file = "blkio.weight";
+        if self.v2 {
+            file = "io.bfq.weight";
+        }
+        self.open_path(file, true).and_then(|mut file| {
+            file.write_all(w.to_string().as_ref())
+                .map_err(|e| Error::with_cause(WriteFailed, e))
+        })
     }
 
     /// Same as `set_weight()`, but settable per each block device.
-    pub fn set_weight_for_device(
-        &self,
-        major: u64,
-        minor: u64,
-        weight: u64,
-    ) -> Result<()> {
-        self.open_path("blkio.weight_device", true)
-            .and_then(|mut file| {
-                file.write_all(format!("{}:{} {}", major, minor, weight).as_ref())
-                    .map_err(|e| Error::with_cause(WriteFailed, e))
-            })
+    pub fn set_weight_for_device(&self, major: u64, minor: u64, weight: u64) -> Result<()> {
+        let mut file = "blkio.weight_device";
+        if self.v2 {
+            // Attation: there is no weight for device in runc
+            // https://github.com/opencontainers/runc/blob/46be7b612e2533c494e6a251111de46d8e286ed5/libcontainer/cgroups/fs2/io.go#L30
+            // may depends on IO schedulers https://wiki.ubuntu.com/Kernel/Reference/IOSchedulers
+            file = "io.bfq.weight";
+        }
+        self.open_path(file, true).and_then(|mut file| {
+            file.write_all(format!("{}:{} {}", major, minor, weight).as_ref())
+                .map_err(|e| Error::with_cause(WriteFailed, e))
+        })
     }
 }
 
@@ -760,10 +856,7 @@ Total 61823067136
     #[test]
     fn test_parse_io_service_total() {
         let ok = parse_io_service_total(TEST_VALUE.to_string()).unwrap();
-        assert_eq!(
-            ok,
-            61823067136
-        );
+        assert_eq!(ok, 61823067136);
     }
 
     #[test]
@@ -811,10 +904,7 @@ Total 61823067136
             ]
         );
         let err = parse_io_service(TEST_WRONG_VALUE.to_string()).unwrap_err();
-        assert_eq!(
-            err.kind(),
-            &ErrorKind::ParseError,
-        );
+        assert_eq!(err.kind(), &ErrorKind::ParseError,);
     }
 
     #[test]
diff --git a/src/cgroup.rs b/src/cgroup.rs
index 45b47db..4fada60 100644
--- a/src/cgroup.rs
+++ b/src/cgroup.rs
@@ -1,16 +1,22 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 Ant Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
 
 //! This module handles cgroup operations. Start here!
 
+use crate::error::ErrorKind::*;
 use crate::error::*;
 
+use crate::libc_rmdir;
+
 use crate::{CgroupPid, ControllIdentifier, Controller, Hierarchy, Resources, Subsystem};
 
+use std::collections::HashMap;
 use std::convert::From;
-use std::path::Path;
+use std::fs;
+use std::path::{Path, PathBuf};
 
 /// A control group is the central structure to this crate.
 ///
@@ -29,27 +35,35 @@ pub struct Cgroup<'b> {
     subsystems: Vec<Subsystem>,
 
     /// The hierarchy.
-    hier: &'b Hierarchy,
+    hier: Box<&'b dyn Hierarchy>,
+    path: String,
 }
 
 impl<'b> Cgroup<'b> {
     /// Create this control group.
     fn create(&self) {
-        for subsystem in &self.subsystems {
-            subsystem.to_controller().create();
+        if self.hier.v2() {
+            create_v2_cgroup(self.hier.root().clone(), &self.path);
+        } else {
+            for subsystem in &self.subsystems {
+                subsystem.to_controller().create();
+            }
         }
     }
 
+    pub fn v2(&self) -> bool {
+        self.hier.v2()
+    }
+
     /// Create a new control group in the hierarchy `hier`, with name `path`.
     ///
     /// Returns a handle to the control group that can be used to manipulate it.
     ///
     /// Note that if the handle goes out of scope and is dropped, the control group is _not_
     /// destroyed.
-    pub fn new<P: AsRef<Path>>(hier: &Hierarchy, path: P) -> Cgroup {
-        let cg = Cgroup::load(hier, path);
-        cg.create();
-        cg
+    pub fn new<P: AsRef<Path>>(hier: Box<&'b dyn Hierarchy>, path: P) -> Cgroup<'b> {
+        let relative_paths = get_cgroups_relative_paths().unwrap();
+        Cgroup::new_with_relative_paths(hier, path, relative_paths)
     }
 
     /// Create a handle for a control group in the hierarchy `hier`, with name `path`.
@@ -59,19 +73,65 @@ impl<'b> Cgroup<'b> {
     ///
     /// Note that if the handle goes out of scope and is dropped, the control group is _not_
     /// destroyed.
-    pub fn load<P: AsRef<Path>>(hier: &Hierarchy, path: P) -> Cgroup {
+    pub fn load<P: AsRef<Path>>(hier: Box<&'b dyn Hierarchy>, path: P) -> Cgroup<'b> {
+        let relative_paths = get_cgroups_relative_paths().unwrap();
+        Cgroup::load_with_relative_paths(hier, path, relative_paths)
+    }
+
+    /// Create a new control group in the hierarchy `hier`, with name `path`.
+    /// and relative paths from `/proc/self/cgroup`
+    ///
+    /// Returns a handle to the control group that can be used to manipulate it.
+    ///
+    /// Note that if the handle goes out of scope and is dropped, the control group is _not_
+    /// destroyed.
+    pub fn new_with_relative_paths<P: AsRef<Path>>(
+        hier: Box<&'b dyn Hierarchy>,
+        path: P,
+        relative_paths: HashMap<String, String>,
+    ) -> Cgroup<'b> {
+        let cg = Cgroup::load_with_relative_paths(hier, path, relative_paths);
+        cg.create();
+        cg
+    }
+
+    /// Create a handle for a control group in the hierarchy `hier`, with name `path`,
+    /// and relative paths from `/proc/self/cgroup`
+    ///
+    /// Returns a handle to the control group (that possibly does not exist until `create()` has
+    /// been called on the cgroup.
+    ///
+    /// Note that if the handle goes out of scope and is dropped, the control group is _not_
+    /// destroyed.
+    pub fn load_with_relative_paths<P: AsRef<Path>>(
+        hier: Box<&'b dyn Hierarchy>,
+        path: P,
+        relative_paths: HashMap<String, String>,
+    ) -> Cgroup<'b> {
         let path = path.as_ref();
         let mut subsystems = hier.subsystems();
         if path.as_os_str() != "" {
             subsystems = subsystems
                 .into_iter()
-                .map(|x| x.enter(path))
+                .map(|x| {
+                    let cn = x.controller_name();
+                    if relative_paths.contains_key(&cn) {
+                        let rp = relative_paths.get(&cn).unwrap();
+                        let valid_path = rp.trim_start_matches("/").to_string();
+                        let mut p = PathBuf::from(valid_path);
+                        p.push(path);
+                        x.enter(p.as_ref())
+                    } else {
+                        x.enter(path)
+                    }
+                })
                 .collect::<Vec<_>>();
         }
 
         let cg = Cgroup {
             subsystems: subsystems,
             hier: hier,
+            path: path.to_str().unwrap().to_string(),
         };
 
         cg
@@ -89,6 +149,15 @@ impl<'b> Cgroup<'b> {
     /// actually removed, and remove the descendants first if not. In the future, this behavior
     /// will change.
     pub fn delete(self) {
+        if self.v2() {
+            if self.path != "" {
+                let mut p = self.hier.root().clone();
+                p.push(self.path);
+                libc_rmdir(p.to_str().unwrap());
+            }
+            return;
+        }
+
         self.subsystems.into_iter().for_each(|sub| match sub {
             Subsystem::Pid(pidc) => pidc.delete(),
             Subsystem::Mem(c) => c.delete(),
@@ -103,6 +172,7 @@ impl<'b> Cgroup<'b> {
             Subsystem::NetPrio(c) => c.delete(),
             Subsystem::HugeTlb(c) => c.delete(),
             Subsystem::Rdma(c) => c.delete(),
+            Subsystem::Systemd(c) => c.delete(),
         });
     }
 
@@ -148,25 +218,120 @@ impl<'b> Cgroup<'b> {
 
     /// Attach a task to the control group.
     pub fn add_task(&self, pid: CgroupPid) -> Result<()> {
-        self.subsystems()
-            .iter()
-            .try_for_each(|sub| sub.to_controller().add_task(&pid))
+        if self.v2() {
+            let subsystems = self.subsystems();
+            if subsystems.len() > 0 {
+                let c = subsystems[0].to_controller();
+                c.add_task(&pid)
+            } else {
+                Ok(())
+            }
+        } else {
+            self.subsystems()
+                .iter()
+                .try_for_each(|sub| sub.to_controller().add_task(&pid))
+        }
     }
 
     /// Returns an Iterator that can be used to iterate over the tasks that are currently in the
     /// control group.
     pub fn tasks(&self) -> Vec<CgroupPid> {
         // Collect the tasks from all subsystems
-        let mut v = self
-            .subsystems()
-            .iter()
-            .map(|x| x.to_controller().tasks())
-            .fold(vec![], |mut acc, mut x| {
-                acc.append(&mut x);
-                acc
-            });
+        let mut v = if self.v2() {
+            let subsystems = self.subsystems();
+            if subsystems.len() > 0 {
+                let c = subsystems[0].to_controller();
+                c.tasks()
+            } else {
+                vec![]
+            }
+        } else {
+            self.subsystems()
+                .iter()
+                .map(|x| x.to_controller().tasks())
+                .fold(vec![], |mut acc, mut x| {
+                    acc.append(&mut x);
+                    acc
+                })
+        };
+
         v.sort();
         v.dedup();
         v
     }
 }
+
+pub const UNIFIED_MOUNTPOINT: &'static str = "/sys/fs/cgroup";
+
+fn enable_controllers(controllers: &Vec<String>, path: &PathBuf) {
+    let mut f = path.clone();
+    f.push("cgroup.subtree_control");
+    for c in controllers {
+        let body = format!("+{}", c);
+        let _rest = fs::write(f.as_path(), body.as_bytes());
+    }
+}
+
+fn supported_controllers(p: &PathBuf) -> Vec<String> {
+    let p = format!("{}/{}", UNIFIED_MOUNTPOINT, "cgroup.controllers");
+    let ret = fs::read_to_string(p.as_str());
+    ret.unwrap_or(String::new())
+        .split(" ")
+        .map(|x| x.to_string())
+        .collect::<Vec<String>>()
+}
+
+fn create_v2_cgroup(root: PathBuf, path: &str) -> Result<()> {
+    // controler list ["memory", "cpu"]
+    let controllers = supported_controllers(&root);
+    let mut fp = root;
+
+    // enable for root
+    enable_controllers(&controllers, &fp);
+
+    // path: "a/b/c"
+    let elements = path.split("/").collect::<Vec<&str>>();
+    let last_index = elements.len() - 1;
+    for (i, ele) in elements.iter().enumerate() {
+        // ROOT/a
+        fp.push(ele);
+        // create dir, need not check if is a file or directory
+        if !fp.exists() {
+            match ::std::fs::create_dir(fp.clone()) {
+                Err(e) => return Err(Error::with_cause(ErrorKind::FsError, e)),
+                Ok(_) => {}
+            }
+        }
+
+        if i < last_index {
+            // enable controllers for substree
+            enable_controllers(&controllers, &fp);
+        }
+    }
+
+    Ok(())
+}
+
+pub fn get_cgroups_relative_paths() -> Result<HashMap<String, String>> {
+    let mut m = HashMap::new();
+    let content =
+        fs::read_to_string("/proc/self/cgroup").map_err(|e| Error::with_cause(ReadFailed, e))?;
+    for l in content.lines() {
+        let fl: Vec<&str> = l.split(':').collect();
+        if fl.len() != 3 {
+            continue;
+        }
+
+        let keys: Vec<&str> = fl[1].split(',').collect();
+        for key in &keys {
+            // this is a workaround, cgroup file are using `name=systemd`,
+            // but if file system the name is `systemd`
+            if *key == "name=systemd" {
+                m.insert("systemd".to_string(), fl[2].to_string());
+            } else {
+                m.insert(key.to_string(), fl[2].to_string());
+            }
+        }
+    }
+    Ok(m)
+}
diff --git a/src/cgroup_builder.rs b/src/cgroup_builder.rs
index 7f5f455..094535c 100644
--- a/src/cgroup_builder.rs
+++ b/src/cgroup_builder.rs
@@ -1,4 +1,5 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 Ant Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
@@ -18,8 +19,9 @@
 //! # use cgroups::*;
 //! # use cgroups::devices::*;
 //! # use cgroups::cgroup_builder::*;
-//! let v1 = cgroups::hierarchies::V1::new();
-//! let cgroup: Cgroup = CgroupBuilder::new("hello", &v1)
+//! let h = cgroups::hierarchies::auto();
+//! let h = Box::new(&*h);
+//! let cgroup: Cgroup = CgroupBuilder::new("hello", h)
 //!      .memory()
 //!          .kernel_memory_limit(1024 * 1024)
 //!          .memory_hard_limit(1024 * 1024)
@@ -45,10 +47,10 @@
 //!          .limit("2G".to_string(), 2 * 1024 * 1024 * 1024)
 //!          .done()
 //!      .blkio()
-//!          .weight(123)
-//!          .leaf_weight(99)
-//!          .weight_device(6, 1, 100, 55)
-//!          .weight_device(6, 1, 100, 55)
+//!          .weight(Some(123))
+//!          .leaf_weight(Some(99))
+//!          .weight_device(6, 1, Some(100), Some(55))
+//!          .weight_device(6, 1, Some(100), Some(55))
 //!          .throttle_iops()
 //!              .read(6, 1, 10)
 //!              .write(11, 1, 100)
@@ -60,7 +62,10 @@
 //! ```
 use crate::error::*;
 
-use crate::{pid, BlkIoDeviceResource, BlkIoDeviceThrottleResource,  Cgroup, DeviceResource, Hierarchy, HugePageResource, NetworkPriority, Resources};
+use crate::{
+    pid, BlkIoDeviceResource, BlkIoDeviceThrottleResource, Cgroup, DeviceResource, Hierarchy,
+    HugePageResource, MaxValue, NetworkPriority, Resources,
+};
 
 macro_rules! gen_setter {
     ($res:ident, $cont:ident, $func:ident, $name:ident, $ty:ty) => {
@@ -70,13 +75,13 @@ macro_rules! gen_setter {
             self.cgroup.resources.$res.$name = $name;
             self
         }
-    }
+    };
 }
 
 /// A control group builder instance
 pub struct CgroupBuilder<'a> {
     name: String,
-    hierarchy: &'a Hierarchy,
+    hierarchy: Box<&'a dyn Hierarchy>,
     /// Internal, unsupported field: use the associated builders instead.
     resources: Resources,
 }
@@ -85,7 +90,7 @@ impl<'a> CgroupBuilder<'a> {
     /// Start building a control group with the supplied hierarchy and name pair.
     ///
     /// Note that this does not actually create the control group until `build()` is called.
-    pub fn new(name: &'a str, hierarchy: &'a Hierarchy) -> CgroupBuilder<'a> {
+    pub fn new(name: &'a str, hierarchy: Box<&'a dyn Hierarchy>) -> CgroupBuilder<'a> {
         CgroupBuilder {
             name: name.to_owned(),
             hierarchy: hierarchy,
@@ -95,46 +100,34 @@ impl<'a> CgroupBuilder<'a> {
 
     /// Builds the memory resources of the control group.
     pub fn memory(self) -> MemoryResourceBuilder<'a> {
-        MemoryResourceBuilder {
-            cgroup: self,
-        }
+        MemoryResourceBuilder { cgroup: self }
     }
 
     /// Builds the pid resources of the control group.
     pub fn pid(self) -> PidResourceBuilder<'a> {
-        PidResourceBuilder {
-            cgroup: self,
-        }
+        PidResourceBuilder { cgroup: self }
     }
 
     /// Builds the cpu resources of the control group.
     pub fn cpu(self) -> CpuResourceBuilder<'a> {
-        CpuResourceBuilder {
-            cgroup: self,
-        }
+        CpuResourceBuilder { cgroup: self }
     }
 
     /// Builds the devices resources of the control group, disallowing or
     /// allowing access to certain devices in the system.
     pub fn devices(self) -> DeviceResourceBuilder<'a> {
-        DeviceResourceBuilder {
-            cgroup: self,
-        }
+        DeviceResourceBuilder { cgroup: self }
     }
 
     /// Builds the network resources of the control group, setting class id, or
     /// various priorities on networking interfaces.
     pub fn network(self) -> NetworkResourceBuilder<'a> {
-        NetworkResourceBuilder {
-            cgroup: self,
-        }
+        NetworkResourceBuilder { cgroup: self }
     }
 
     /// Builds the hugepage/hugetlb resources available to the control group.
     pub fn hugepages(self) -> HugepagesResourceBuilder<'a> {
-        HugepagesResourceBuilder {
-            cgroup: self,
-        }
+        HugepagesResourceBuilder { cgroup: self }
     }
 
     /// Builds the block I/O resources available for the control group.
@@ -159,12 +152,35 @@ pub struct MemoryResourceBuilder<'a> {
 }
 
 impl<'a> MemoryResourceBuilder<'a> {
-
-    gen_setter!(memory, MemController, set_kmem_limit, kernel_memory_limit, u64);
-    gen_setter!(memory, MemController, set_limit, memory_hard_limit, u64);
-    gen_setter!(memory, MemController, set_soft_limit, memory_soft_limit, u64);
-    gen_setter!(memory, MemController, set_tcp_limit, kernel_tcp_memory_limit, u64);
-    gen_setter!(memory, MemController, set_memswap_limit, memory_swap_limit, u64);
+    gen_setter!(
+        memory,
+        MemController,
+        set_kmem_limit,
+        kernel_memory_limit,
+        i64
+    );
+    gen_setter!(memory, MemController, set_limit, memory_hard_limit, i64);
+    gen_setter!(
+        memory,
+        MemController,
+        set_soft_limit,
+        memory_soft_limit,
+        i64
+    );
+    gen_setter!(
+        memory,
+        MemController,
+        set_tcp_limit,
+        kernel_tcp_memory_limit,
+        i64
+    );
+    gen_setter!(
+        memory,
+        MemController,
+        set_memswap_limit,
+        memory_swap_limit,
+        i64
+    );
     gen_setter!(memory, MemController, set_swappiness, swappiness, u64);
 
     /// Finish the construction of the memory resources of a control group.
@@ -179,8 +195,13 @@ pub struct PidResourceBuilder<'a> {
 }
 
 impl<'a> PidResourceBuilder<'a> {
-
-    gen_setter!(pid, PidController, set_pid_max, maximum_number_of_processes, pid::PidMax);
+    gen_setter!(
+        pid,
+        PidController,
+        set_pid_max,
+        maximum_number_of_processes,
+        MaxValue
+    );
 
     /// Finish the construction of the pid resources of a control group.
     pub fn done(self) -> CgroupBuilder<'a> {
@@ -194,8 +215,8 @@ pub struct CpuResourceBuilder<'a> {
 }
 
 impl<'a> CpuResourceBuilder<'a> {
-
-    gen_setter!(cpu, CpuSetController, set_cpus, cpus, String);
+    // FIXME this should all changed to options.
+    gen_setter!(cpu, CpuSetController, set_cpus, cpus, Option<String>);
     gen_setter!(cpu, CpuSetController, set_mems, mems, String);
     gen_setter!(cpu, CpuController, set_shares, shares, u64);
     gen_setter!(cpu, CpuController, set_cfs_quota, quota, i64);
@@ -215,22 +236,22 @@ pub struct DeviceResourceBuilder<'a> {
 }
 
 impl<'a> DeviceResourceBuilder<'a> {
-
     /// Restrict (or allow) a device to the tasks inside the control group.
-    pub fn device(mut self,
-                  major: i64,
-                  minor: i64,
-                  devtype: crate::devices::DeviceType,
-                  allow: bool,
-                  access: Vec<crate::devices::DevicePermissions>)
-            -> DeviceResourceBuilder<'a> {
+    pub fn device(
+        mut self,
+        major: i64,
+        minor: i64,
+        devtype: crate::devices::DeviceType,
+        allow: bool,
+        access: Vec<crate::devices::DevicePermissions>,
+    ) -> DeviceResourceBuilder<'a> {
         self.cgroup.resources.devices.update_values = true;
         self.cgroup.resources.devices.devices.push(DeviceResource {
             major,
             minor,
             devtype,
             allow,
-            access
+            access,
         });
         self
     }
@@ -247,18 +268,17 @@ pub struct NetworkResourceBuilder<'a> {
 }
 
 impl<'a> NetworkResourceBuilder<'a> {
-
     gen_setter!(network, NetclsController, set_class, class_id, u64);
 
     /// Set the priority of the tasks when operating on a networking device defined by `name` to be
     /// `priority`.
-    pub fn priority(mut self, name: String, priority: u64)
-        -> NetworkResourceBuilder<'a> {
+    pub fn priority(mut self, name: String, priority: u64) -> NetworkResourceBuilder<'a> {
         self.cgroup.resources.network.update_values = true;
-        self.cgroup.resources.network.priorities.push(NetworkPriority {
-            name,
-            priority,
-        });
+        self.cgroup
+            .resources
+            .network
+            .priorities
+            .push(NetworkPriority { name, priority });
         self
     }
 
@@ -274,15 +294,14 @@ pub struct HugepagesResourceBuilder<'a> {
 }
 
 impl<'a> HugepagesResourceBuilder<'a> {
-
     /// Limit the usage of certain hugepages (determined by `size`) to be at most `limit` bytes.
-    pub fn limit(mut self, size: String, limit: u64)
-        -> HugepagesResourceBuilder<'a> {
+    pub fn limit(mut self, size: String, limit: u64) -> HugepagesResourceBuilder<'a> {
         self.cgroup.resources.hugepages.update_values = true;
-        self.cgroup.resources.hugepages.limits.push(HugePageResource {
-            size,
-            limit,
-        });
+        self.cgroup
+            .resources
+            .hugepages
+            .limits
+            .push(HugePageResource { size, limit });
         self
     }
 
@@ -299,24 +318,34 @@ pub struct BlkIoResourcesBuilder<'a> {
 }
 
 impl<'a> BlkIoResourcesBuilder<'a> {
-
-    gen_setter!(blkio, BlkIoController, set_weight, weight, u16);
-    gen_setter!(blkio, BlkIoController, set_leaf_weight, leaf_weight, u16);
+    gen_setter!(blkio, BlkIoController, set_weight, weight, Option<u16>);
+    gen_setter!(
+        blkio,
+        BlkIoController,
+        set_leaf_weight,
+        leaf_weight,
+        Option<u16>
+    );
 
     /// Set the weight of a certain device.
-    pub fn weight_device(mut self,
-                         major: u64,
-                         minor: u64,
-                         weight: u16,
-                         leaf_weight: u16)
-        -> BlkIoResourcesBuilder<'a> {
+    pub fn weight_device(
+        mut self,
+        major: u64,
+        minor: u64,
+        weight: Option<u16>,
+        leaf_weight: Option<u16>,
+    ) -> BlkIoResourcesBuilder<'a> {
         self.cgroup.resources.blkio.update_values = true;
-        self.cgroup.resources.blkio.weight_device.push(BlkIoDeviceResource {
-            major,
-            minor,
-            weight,
-            leaf_weight,
-        });
+        self.cgroup
+            .resources
+            .blkio
+            .weight_device
+            .push(BlkIoDeviceResource {
+                major,
+                minor,
+                weight,
+                leaf_weight,
+            });
         self
     }
 
@@ -333,35 +362,41 @@ impl<'a> BlkIoResourcesBuilder<'a> {
     }
 
     /// Limit the read rate of the current metric for a certain device.
-    pub fn read(mut self, major: u64, minor: u64, rate: u64)
-        -> BlkIoResourcesBuilder<'a> {
+    pub fn read(mut self, major: u64, minor: u64, rate: u64) -> BlkIoResourcesBuilder<'a> {
         self.cgroup.resources.blkio.update_values = true;
-        let throttle = BlkIoDeviceThrottleResource {
-            major,
-            minor,
-            rate,
-        };
+        let throttle = BlkIoDeviceThrottleResource { major, minor, rate };
         if self.throttling_iops {
-            self.cgroup.resources.blkio.throttle_read_iops_device.push(throttle);
+            self.cgroup
+                .resources
+                .blkio
+                .throttle_read_iops_device
+                .push(throttle);
         } else {
-            self.cgroup.resources.blkio.throttle_read_bps_device.push(throttle);
+            self.cgroup
+                .resources
+                .blkio
+                .throttle_read_bps_device
+                .push(throttle);
         }
         self
     }
 
     /// Limit the write rate of the current metric for a certain device.
-    pub fn write(mut self, major: u64, minor: u64, rate: u64)
-        -> BlkIoResourcesBuilder<'a> {
+    pub fn write(mut self, major: u64, minor: u64, rate: u64) -> BlkIoResourcesBuilder<'a> {
         self.cgroup.resources.blkio.update_values = true;
-        let throttle = BlkIoDeviceThrottleResource {
-            major,
-            minor,
-            rate,
-        };
+        let throttle = BlkIoDeviceThrottleResource { major, minor, rate };
         if self.throttling_iops {
-            self.cgroup.resources.blkio.throttle_write_iops_device.push(throttle);
+            self.cgroup
+                .resources
+                .blkio
+                .throttle_write_iops_device
+                .push(throttle);
         } else {
-            self.cgroup.resources.blkio.throttle_write_bps_device.push(throttle);
+            self.cgroup
+                .resources
+                .blkio
+                .throttle_write_bps_device
+                .push(throttle);
         }
         self
     }
diff --git a/src/cpu.rs b/src/cpu.rs
index c4fc792..ad8f3bf 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -1,4 +1,5 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 Ant Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
@@ -12,8 +13,8 @@ use std::fs::File;
 use std::io::{Read, Write};
 use std::path::PathBuf;
 
-use crate::error::*;
 use crate::error::ErrorKind::*;
+use crate::error::*;
 
 use crate::{
     ControllIdentifier, ControllerInternal, Controllers, CpuResources, Resources, Subsystem,
@@ -28,6 +29,7 @@ use crate::{
 pub struct CpuController {
     base: PathBuf,
     path: PathBuf,
+    v2: bool,
 }
 
 /// The current state of the control group and its processes.
@@ -56,12 +58,15 @@ impl ControllerInternal for CpuController {
         &self.base
     }
 
+    fn is_v2(&self) -> bool {
+        self.v2
+    }
+
     fn apply(&self, res: &Resources) -> Result<()> {
         // get the resources that apply to this controller
         let res: &CpuResources = &res.cpu;
 
         if res.update_values {
-            // apply pid_max
             let _ = self.set_shares(res.shares);
             if self.shares()? != res.shares as u64 {
                 return Err(Error::new(ErrorKind::Other));
@@ -107,19 +112,25 @@ impl<'a> From<&'a Subsystem> for &'a CpuController {
 fn read_u64_from(mut file: File) -> Result<u64> {
     let mut string = String::new();
     match file.read_to_string(&mut string) {
-        Ok(_) => string.trim().parse().map_err(|e| Error::with_cause(ParseError, e)),
+        Ok(_) => string
+            .trim()
+            .parse()
+            .map_err(|e| Error::with_cause(ParseError, e)),
         Err(e) => Err(Error::with_cause(ReadFailed, e)),
     }
 }
 
 impl CpuController {
     /// Contructs a new `CpuController` with `oroot` serving as the root of the control group.
-    pub fn new(oroot: PathBuf) -> Self {
+    pub fn new(oroot: PathBuf, v2: bool) -> Self {
         let mut root = oroot;
-        root.push(Self::controller_type().to_string());
+        if !v2 {
+            root.push(Self::controller_type().to_string());
+        }
         Self {
             base: root.clone(),
             path: root,
+            v2: v2,
         }
     }
 
@@ -135,7 +146,8 @@ impl CpuController {
                         Ok(_) => Ok(s),
                         Err(e) => Err(Error::with_cause(ReadFailed, e)),
                     }
-                }).unwrap_or("".to_string()),
+                })
+                .unwrap_or("".to_string()),
         }
     }
 
@@ -146,7 +158,12 @@ impl CpuController {
     /// `shares` to `200` ensures that control group `B` receives twice as much as CPU bandwidth.
     /// (Assuming both `A` and `B` are of the same parent)
     pub fn set_shares(&self, shares: u64) -> Result<()> {
-        self.open_path("cpu.shares", true).and_then(|mut file| {
+        let mut file = "cpu.shares";
+        if self.v2 {
+            file = "cpu.weight";
+        }
+        // NOTE: .CpuShares is not used here. Conversion is the caller's responsibility.
+        self.open_path(file, true).and_then(|mut file| {
             file.write_all(shares.to_string().as_ref())
                 .map_err(|e| Error::with_cause(WriteFailed, e))
         })
@@ -155,7 +172,11 @@ impl CpuController {
     /// Retrieve the CPU bandwidth that this control group (relative to other control groups and
     /// this control group's parent) can use.
     pub fn shares(&self) -> Result<u64> {
-        self.open_path("cpu.shares", false).and_then(read_u64_from)
+        let mut file = "cpu.shares";
+        if self.v2 {
+            file = "cpu.weight";
+        }
+        self.open_path(file, false).and_then(read_u64_from)
     }
 
     /// Specify a period (when using the CFS scheduler) of time in microseconds for how often this
@@ -191,4 +212,43 @@ impl CpuController {
         self.open_path("cpu.cfs_quota_us", false)
             .and_then(read_u64_from)
     }
+
+    pub fn set_cfs_quota_and_period(&self, quota: u64, period: u64) -> Result<()> {
+        if !self.v2 {
+            self.set_cfs_quota(quota)?;
+            return self.set_cfs_period(period);
+        }
+        let mut line = "max".to_string();
+        if quota > 0 {
+            line = quota.to_string();
+        }
+
+        let mut p = period;
+        if period == 0 {
+            // This default value is documented in
+            // https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html
+            p = 100000
+        }
+        line = format!("{} {}", line, p);
+        self.open_path("cpu.max", true).and_then(|mut file| {
+            file.write_all(line.as_ref())
+                .map_err(|e| Error::with_cause(WriteFailed, e))
+        })
+    }
+
+    pub fn set_rt_runtime(&self, us: i64) -> Result<()> {
+        self.open_path("cpu.rt_runtime_us", true)
+            .and_then(|mut file| {
+                file.write_all(us.to_string().as_ref())
+                    .map_err(|e| Error::with_cause(WriteFailed, e))
+            })
+    }
+
+    pub fn set_rt_period_us(&self, us: u64) -> Result<()> {
+        self.open_path("cpu.rt_period_us", true)
+            .and_then(|mut file| {
+                file.write_all(us.to_string().as_ref())
+                    .map_err(|e| Error::with_cause(WriteFailed, e))
+            })
+    }
 }
diff --git a/src/cpuacct.rs b/src/cpuacct.rs
index 0325723..4171c6d 100644
--- a/src/cpuacct.rs
+++ b/src/cpuacct.rs
@@ -11,8 +11,8 @@ use std::fs::File;
 use std::io::{Read, Write};
 use std::path::PathBuf;
 
-use crate::error::*;
 use crate::error::ErrorKind::*;
+use crate::error::*;
 
 use crate::{ControllIdentifier, ControllerInternal, Controllers, Resources, Subsystem};
 
@@ -167,7 +167,9 @@ impl CpuAcctController {
 
     /// Reset the statistics the kernel has gathered about the control group.
     pub fn reset(&self) -> Result<()> {
-        self.open_path("cpuacct.usage", true)
-            .and_then(|mut file| file.write_all(b"0").map_err(|e| Error::with_cause(WriteFailed, e)))
+        self.open_path("cpuacct.usage", true).and_then(|mut file| {
+            file.write_all(b"0")
+                .map_err(|e| Error::with_cause(WriteFailed, e))
+        })
     }
 }
diff --git a/src/cpuset.rs b/src/cpuset.rs
index 12d757a..92754c0 100644
--- a/src/cpuset.rs
+++ b/src/cpuset.rs
@@ -1,4 +1,5 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 Ant Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
@@ -7,12 +8,14 @@
 //!
 //! See the Kernel's documentation for more information about this subsystem, found at:
 //!  [Documentation/cgroup-v1/cpusets.txt](https://www.kernel.org/doc/Documentation/cgroup-v1/cpusets.txt)
+
+use log::*;
 use std::fs::File;
 use std::io::{Read, Write};
 use std::path::PathBuf;
 
-use crate::error::*;
 use crate::error::ErrorKind::*;
+use crate::error::*;
 
 use crate::{
     ControllIdentifier, ControllerInternal, Controllers, CpuResources, Resources, Subsystem,
@@ -26,6 +29,7 @@ use crate::{
 pub struct CpuSetController {
     base: PathBuf,
     path: PathBuf,
+    v2: bool,
 }
 
 /// The current state of the `cpuset` controller for this control group.
@@ -98,17 +102,93 @@ impl ControllerInternal for CpuSetController {
         &self.base
     }
 
+    fn is_v2(&self) -> bool {
+        self.v2
+    }
+
     fn apply(&self, res: &Resources) -> Result<()> {
         // get the resources that apply to this controller
         let res: &CpuResources = &res.cpu;
 
         if res.update_values {
-            let _ = self.set_cpus(&res.cpus);
+            if res.cpus.is_some() {
+                let _ = self.set_cpus(res.cpus.as_ref().unwrap().as_str());
+            }
             let _ = self.set_mems(&res.mems);
         }
 
         Ok(())
     }
+
+    fn post_create(&self) {
+        if self.is_v2() {
+            return;
+        }
+        let current = self.get_path();
+        let parent = match current.parent() {
+            Some(p) => p,
+            None => return,
+        };
+
+        if current != self.get_base() {
+            match copy_from_parent(current.to_str().unwrap(), "cpuset.cpus") {
+                Ok(_) => (),
+                Err(err) => error!("error create_dir for cpuset.cpus {:?}", err),
+            }
+            match copy_from_parent(current.to_str().unwrap(), "cpuset.mems") {
+                Ok(_) => (),
+                Err(err) => error!("error create_dir for cpuset.mems {:?}", err),
+            }
+        }
+    }
+}
+
+fn find_no_empty_parent(from: &str, file: &str) -> Result<(String, Vec<PathBuf>)> {
+    let mut current_path = ::std::path::Path::new(from).to_path_buf();
+    let mut v = vec![];
+
+    loop {
+        let current_value =
+            match ::std::fs::read_to_string(current_path.clone().join(file).to_str().unwrap()) {
+                Ok(cpus) => String::from(cpus.trim()),
+                Err(e) => return Err(Error::with_cause(ReadFailed, e)),
+            };
+
+        if current_value != "" {
+            return Ok((current_value, v));
+        }
+        v.push(current_path.clone());
+
+        let parent = match current_path.parent() {
+            Some(p) => p,
+            None => return Ok(("".to_string(), v)),
+        };
+
+        // next loop, find parent
+        current_path = parent.to_path_buf();
+    }
+}
+
+/// copy_from_parent copy the cpuset.cpus and cpuset.mems from the parent
+/// directory to the current directory if the file's contents are 0
+fn copy_from_parent(current: &str, file: &str) -> Result<()> {
+    // find not empty cpus/memes from current directory.
+    let (value, parents) = find_no_empty_parent(current, file)?;
+
+    if value == "" || parents.len() == 0 {
+        return Ok(());
+    }
+
+    for p in parents.iter().rev() {
+        let mut pb = p.clone();
+        pb.push(file);
+        match ::std::fs::write(pb.to_str().unwrap(), value.as_bytes()) {
+            Ok(_) => (),
+            Err(e) => return Err(Error::with_cause(WriteFailed, e)),
+        }
+    }
+
+    Ok(())
 }
 
 impl ControllIdentifier for CpuSetController {
@@ -142,7 +222,10 @@ fn read_string_from(mut file: File) -> Result<String> {
 fn read_u64_from(mut file: File) -> Result<u64> {
     let mut string = String::new();
     match file.read_to_string(&mut string) {
-        Ok(_) => string.trim().parse().map_err(|e| Error::with_cause(ParseError, e)),
+        Ok(_) => string
+            .trim()
+            .parse()
+            .map_err(|e| Error::with_cause(ParseError, e)),
         Err(e) => Err(Error::with_cause(ReadFailed, e)),
     }
 }
@@ -186,12 +269,15 @@ fn parse_range(s: String) -> Result<Vec<(u64, u64)>> {
 
 impl CpuSetController {
     /// Contructs a new `CpuSetController` with `oroot` serving as the root of the control group.
-    pub fn new(oroot: PathBuf) -> Self {
+    pub fn new(oroot: PathBuf, v2: bool) -> Self {
         let mut root = oroot;
-        root.push(Self::controller_type().to_string());
+        if !v2 {
+            root.push(Self::controller_type().to_string());
+        }
         Self {
             base: root.clone(),
             path: root,
+            v2: v2,
         }
     }
 
@@ -290,9 +376,11 @@ impl CpuSetController {
         self.open_path("cpuset.cpu_exclusive", true)
             .and_then(|mut file| {
                 if b {
-                    file.write_all(b"1").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"1")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 } else {
-                    file.write_all(b"0").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"0")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 }
             })
     }
@@ -303,9 +391,11 @@ impl CpuSetController {
         self.open_path("cpuset.mem_exclusive", true)
             .and_then(|mut file| {
                 if b {
-                    file.write_all(b"1").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"1")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 } else {
-                    file.write_all(b"0").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"0")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 }
             })
     }
@@ -340,9 +430,11 @@ impl CpuSetController {
         self.open_path("cpuset.mem_hardwall", true)
             .and_then(|mut file| {
                 if b {
-                    file.write_all(b"1").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"1")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 } else {
-                    file.write_all(b"0").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"0")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 }
             })
     }
@@ -353,9 +445,11 @@ impl CpuSetController {
         self.open_path("cpuset.sched_load_balance", true)
             .and_then(|mut file| {
                 if b {
-                    file.write_all(b"1").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"1")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 } else {
-                    file.write_all(b"0").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"0")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 }
             })
     }
@@ -377,9 +471,11 @@ impl CpuSetController {
         self.open_path("cpuset.memory_migrate", true)
             .and_then(|mut file| {
                 if b {
-                    file.write_all(b"1").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"1")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 } else {
-                    file.write_all(b"0").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"0")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 }
             })
     }
@@ -390,9 +486,11 @@ impl CpuSetController {
         self.open_path("cpuset.memory_spread_page", true)
             .and_then(|mut file| {
                 if b {
-                    file.write_all(b"1").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"1")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 } else {
-                    file.write_all(b"0").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"0")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 }
             })
     }
@@ -403,9 +501,11 @@ impl CpuSetController {
         self.open_path("cpuset.memory_spread_slab", true)
             .and_then(|mut file| {
                 if b {
-                    file.write_all(b"1").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"1")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 } else {
-                    file.write_all(b"0").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"0")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 }
             })
     }
@@ -422,9 +522,11 @@ impl CpuSetController {
         self.open_path("cpuset.memory_pressure_enabled", true)
             .and_then(|mut file| {
                 if b {
-                    file.write_all(b"1").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"1")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 } else {
-                    file.write_all(b"0").map_err(|e| Error::with_cause(WriteFailed, e))
+                    file.write_all(b"0")
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
                 }
             })
     }
diff --git a/src/devices.rs b/src/devices.rs
index 09628c4..5e6efb9 100644
--- a/src/devices.rs
+++ b/src/devices.rs
@@ -12,8 +12,8 @@ use std::path::PathBuf;
 
 use log::*;
 
-use crate::error::*;
 use crate::error::ErrorKind::*;
+use crate::error::*;
 
 use crate::{
     ControllIdentifier, ControllerInternal, Controllers, DeviceResource, DeviceResources,
@@ -129,8 +129,7 @@ impl DevicePermissions {
             return Ok(v);
         }
         for e in s.chars() {
-            let perm = DevicePermissions::from_char(e)
-                .ok_or_else(|| Error::new(ParseError))?;
+            let perm = DevicePermissions::from_char(e).ok_or_else(|| Error::new(ParseError))?;
             v.push(perm);
         }
 
diff --git a/src/error.rs b/src/error.rs
index 59f3cca..ff5549c 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -1,4 +1,5 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 Ant Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
@@ -9,6 +10,9 @@ use std::fmt;
 /// The different types of errors that can occur while manipulating control groups.
 #[derive(Debug, Eq, PartialEq)]
 pub enum ErrorKind {
+    FsError,
+    Common(String),
+
     /// An error occured while writing to a control group file.
     WriteFailed,
 
@@ -32,6 +36,8 @@ pub enum ErrorKind {
     /// This crate checks against this and operations will fail with this error.
     InvalidPath,
 
+    InvalidBytesSize,
+
     /// An unknown error has occured.
     Other,
 }
@@ -44,13 +50,16 @@ pub struct Error {
 
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let msg = match self.kind {
-            ErrorKind::WriteFailed => "unable to write to a control group file",
-            ErrorKind::ReadFailed => "unable to read a control group file",
-            ErrorKind::ParseError => "unable to parse control group file",
-            ErrorKind::InvalidOperation => "the requested operation is invalid",
-            ErrorKind::InvalidPath => "the given path is invalid",
-            ErrorKind::Other => "an unknown error",
+        let msg = match &self.kind {
+            ErrorKind::FsError => "fs error".to_string(),
+            ErrorKind::Common(s) => s.clone(),
+            ErrorKind::WriteFailed => "unable to write to a control group file".to_string(),
+            ErrorKind::ReadFailed => "unable to read a control group file".to_string(),
+            ErrorKind::ParseError => "unable to parse control group file".to_string(),
+            ErrorKind::InvalidOperation => "the requested operation is invalid".to_string(),
+            ErrorKind::InvalidPath => "the given path is invalid".to_string(),
+            ErrorKind::InvalidBytesSize => "invalid bytes size".to_string(),
+            ErrorKind::Other => "an unknown error".to_string(),
         };
 
         write!(f, "{}", msg)
@@ -67,12 +76,15 @@ impl StdError for Error {
 }
 
 impl Error {
-    pub(crate) fn new(kind: ErrorKind) -> Self {
+    pub(crate) fn from_string(s: String) -> Self {
         Self {
-            kind,
+            kind: ErrorKind::Common(s),
             cause: None,
         }
     }
+    pub(crate) fn new(kind: ErrorKind) -> Self {
+        Self { kind, cause: None }
+    }
 
     pub(crate) fn with_cause<E>(kind: ErrorKind, cause: E) -> Self
     where
diff --git a/src/events.rs b/src/events.rs
new file mode 100644
index 0000000..da0b718
--- /dev/null
+++ b/src/events.rs
@@ -0,0 +1,90 @@
+// Copyright (c) 2020 Ant Group
+//
+// SPDX-License-Identifier: Apache-2.0 or MIT
+//
+
+use eventfd::{eventfd, EfdFlags};
+use nix::sys::eventfd;
+use std::fs::{self, File};
+use std::io::Read;
+use std::os::unix::io::{AsRawFd, FromRawFd};
+use std::path::{Path, PathBuf};
+use std::sync::mpsc::{self, Receiver};
+use std::thread;
+
+use crate::error::ErrorKind::*;
+use crate::error::*;
+
+// notify_on_oom returns channel on which you can expect event about OOM,
+// if process died without OOM this channel will be closed.
+pub fn notify_on_oom_v2(key: &str, dir: &PathBuf) -> Result<Receiver<String>> {
+    register_memory_event(key, dir, "memory.oom_control", "")
+}
+
+// notify_on_oom returns channel on which you can expect event about OOM,
+// if process died without OOM this channel will be closed.
+pub fn notify_on_oom_v1(key: &str, dir: &PathBuf) -> Result<Receiver<String>> {
+    register_memory_event(key, dir, "memory.oom_control", "")
+}
+
+// level is one of "low", "medium", or "critical"
+pub fn notify_memory_pressure(key: &str, dir: &PathBuf, level: &str) -> Result<Receiver<String>> {
+    if level != "low" && level != "medium" && level != "critical" {
+        return Err(Error::from_string(format!(
+            "invalid pressure level {}",
+            level
+        )));
+    }
+
+    register_memory_event(key, dir, "memory.pressure_level", level)
+}
+
+fn register_memory_event(
+    key: &str,
+    cg_dir: &PathBuf,
+    event_name: &str,
+    arg: &str,
+) -> Result<Receiver<String>> {
+    let path = cg_dir.join(event_name);
+    let event_file = File::open(path).map_err(|e| Error::with_cause(ReadFailed, e))?;
+
+    let eventfd =
+        eventfd(0, EfdFlags::EFD_CLOEXEC).map_err(|e| Error::with_cause(ReadFailed, e))?;
+
+    let event_control_path = cg_dir.join("cgroup.event_control");
+    let data;
+    if arg == "" {
+        data = format!("{} {}", eventfd, event_file.as_raw_fd());
+    } else {
+        data = format!("{} {} {}", eventfd, event_file.as_raw_fd(), arg);
+    }
+
+    // write to file and set mode to 0700(FIXME)
+    fs::write(&event_control_path, data).map_err(|e| Error::with_cause(WriteFailed, e));
+
+    let mut eventfd_file = unsafe { File::from_raw_fd(eventfd) };
+
+    let (sender, receiver) = mpsc::channel();
+    let key = key.to_string();
+
+    thread::spawn(move || {
+        loop {
+            let mut buf = [0; 8];
+            match eventfd_file.read(&mut buf) {
+                Err(err) => {
+                    return;
+                }
+                Ok(_) => {}
+            }
+
+            // When a cgroup is destroyed, an event is sent to eventfd.
+            // So if the control path is gone, return instead of notifying.
+            if !Path::new(&event_control_path).exists() {
+                return;
+            }
+            sender.send(key.clone()).unwrap();
+        }
+    });
+
+    Ok(receiver)
+}
diff --git a/src/freezer.rs b/src/freezer.rs
index 53e2d9d..92d8c2c 100644
--- a/src/freezer.rs
+++ b/src/freezer.rs
@@ -1,4 +1,5 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 Ant Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
@@ -10,8 +11,8 @@
 use std::io::{Read, Write};
 use std::path::PathBuf;
 
-use crate::error::*;
 use crate::error::ErrorKind::*;
+use crate::error::*;
 
 use crate::{ControllIdentifier, ControllerInternal, Controllers, Resources, Subsystem};
 
@@ -27,6 +28,7 @@ use crate::{ControllIdentifier, ControllerInternal, Controllers, Resources, Subs
 pub struct FreezerController {
     base: PathBuf,
     path: PathBuf,
+    v2: bool,
 }
 
 /// The current state of the control group
@@ -80,40 +82,62 @@ impl<'a> From<&'a Subsystem> for &'a FreezerController {
 
 impl FreezerController {
     /// Contructs a new `FreezerController` with `oroot` serving as the root of the control group.
-    pub fn new(oroot: PathBuf) -> Self {
+    pub fn new(oroot: PathBuf, v2: bool) -> Self {
         let mut root = oroot;
-        root.push(Self::controller_type().to_string());
+        if !v2 {
+            root.push(Self::controller_type().to_string());
+        }
         Self {
             base: root.clone(),
             path: root,
+            v2: v2,
         }
     }
 
     /// Freezes the processes in the control group.
     pub fn freeze(&self) -> Result<()> {
-        self.open_path("freezer.state", true).and_then(|mut file| {
-            file.write_all("FROZEN".to_string().as_ref())
+        let mut file = "freezer.state";
+        let mut content = "FROZEN".to_string();
+        if self.v2 {
+            file = "cgroup.freeze";
+            content = "1".to_string();
+        }
+
+        self.open_path(file, true).and_then(|mut file| {
+            file.write_all(content.as_ref())
                 .map_err(|e| Error::with_cause(WriteFailed, e))
         })
     }
 
     /// Thaws, that is, unfreezes the processes in the control group.
     pub fn thaw(&self) -> Result<()> {
-        self.open_path("freezer.state", true).and_then(|mut file| {
-            file.write_all("THAWED".to_string().as_ref())
+        let mut file = "freezer.state";
+        let mut content = "THAWED".to_string();
+        if self.v2 {
+            file = "cgroup.freeze";
+            content = "0".to_string();
+        }
+        self.open_path(file, true).and_then(|mut file| {
+            file.write_all(content.as_ref())
                 .map_err(|e| Error::with_cause(WriteFailed, e))
         })
     }
 
     /// Retrieve the state of processes in the control group.
     pub fn state(&self) -> Result<FreezerState> {
-        self.open_path("freezer.state", false).and_then(|mut file| {
+        let mut file = "freezer.state";
+        if self.v2 {
+            file = "cgroup.freeze";
+        }
+        self.open_path(file, false).and_then(|mut file| {
             let mut s = String::new();
             let res = file.read_to_string(&mut s);
             match res {
                 Ok(_) => match s.as_ref() {
                     "FROZEN" => Ok(FreezerState::Frozen),
                     "THAWED" => Ok(FreezerState::Thawed),
+                    "1" => Ok(FreezerState::Frozen),
+                    "0" => Ok(FreezerState::Thawed),
                     "FREEZING" => Ok(FreezerState::Freezing),
                     _ => Err(Error::new(ParseError)),
                 },
diff --git a/src/hierarchies.rs b/src/hierarchies.rs
index 43b7fe9..4b8f1eb 100644
--- a/src/hierarchies.rs
+++ b/src/hierarchies.rs
@@ -1,4 +1,5 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 Ant Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
@@ -7,8 +8,9 @@
 //!
 //! Currently, we only support the cgroupv1 hierarchy, but in the future we will add support for
 //! the Unified Hierarchy.
+use nix::sys::statfs;
 
-use std::fs::File;
+use std::fs::{self, File};
 use std::io::BufRead;
 use std::io::BufReader;
 use std::path::{Path, PathBuf};
@@ -28,6 +30,7 @@ use crate::net_prio::NetPrioController;
 use crate::perf_event::PerfEventController;
 use crate::pid::PidController;
 use crate::rdma::RdmaController;
+use crate::systemd::SystemdController;
 use crate::{Controllers, Hierarchy, Subsystem};
 
 use crate::cgroup::Cgroup;
@@ -37,35 +40,46 @@ pub struct V1 {
     mount_point: String,
 }
 
+pub struct V2 {
+    root: String,
+}
+
 impl Hierarchy for V1 {
+    fn v2(&self) -> bool {
+        false
+    }
+
     fn subsystems(&self) -> Vec<Subsystem> {
         let mut subs = vec![];
         if self.check_support(Controllers::Pids) {
-            subs.push(Subsystem::Pid(PidController::new(self.root())));
+            subs.push(Subsystem::Pid(PidController::new(self.root(), false)));
         }
         if self.check_support(Controllers::Mem) {
-            subs.push(Subsystem::Mem(MemController::new(self.root())));
+            subs.push(Subsystem::Mem(MemController::new(self.root(), false)));
         }
         if self.check_support(Controllers::CpuSet) {
-            subs.push(Subsystem::CpuSet(CpuSetController::new(self.root())));
+            subs.push(Subsystem::CpuSet(CpuSetController::new(self.root(), false)));
         }
         if self.check_support(Controllers::CpuAcct) {
             subs.push(Subsystem::CpuAcct(CpuAcctController::new(self.root())));
         }
         if self.check_support(Controllers::Cpu) {
-            subs.push(Subsystem::Cpu(CpuController::new(self.root())));
+            subs.push(Subsystem::Cpu(CpuController::new(self.root(), false)));
         }
         if self.check_support(Controllers::Devices) {
             subs.push(Subsystem::Devices(DevicesController::new(self.root())));
         }
         if self.check_support(Controllers::Freezer) {
-            subs.push(Subsystem::Freezer(FreezerController::new(self.root())));
+            subs.push(Subsystem::Freezer(FreezerController::new(
+                self.root(),
+                false,
+            )));
         }
         if self.check_support(Controllers::NetCls) {
             subs.push(Subsystem::NetCls(NetClsController::new(self.root())));
         }
         if self.check_support(Controllers::BlkIo) {
-            subs.push(Subsystem::BlkIo(BlkIoController::new(self.root())));
+            subs.push(Subsystem::BlkIo(BlkIoController::new(self.root(), false)));
         }
         if self.check_support(Controllers::PerfEvent) {
             subs.push(Subsystem::PerfEvent(PerfEventController::new(self.root())));
@@ -74,17 +88,27 @@ impl Hierarchy for V1 {
             subs.push(Subsystem::NetPrio(NetPrioController::new(self.root())));
         }
         if self.check_support(Controllers::HugeTlb) {
-            subs.push(Subsystem::HugeTlb(HugeTlbController::new(self.root())));
+            subs.push(Subsystem::HugeTlb(HugeTlbController::new(
+                self.root(),
+                false,
+            )));
         }
         if self.check_support(Controllers::Rdma) {
             subs.push(Subsystem::Rdma(RdmaController::new(self.root())));
         }
+        if self.check_support(Controllers::Systemd) {
+            subs.push(Subsystem::Systemd(SystemdController::new(
+                self.root(),
+                false,
+            )));
+        }
 
         subs
     }
 
     fn root_control_group(&self) -> Cgroup {
-        Cgroup::load(self, "".to_string())
+        let b: &Hierarchy = self as &Hierarchy;
+        Cgroup::load(Box::new(&*b), "".to_string())
     }
 
     fn check_support(&self, sub: Controllers) -> bool {
@@ -104,10 +128,77 @@ impl Hierarchy for V1 {
     }
 }
 
+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 controller_list: Vec<&str> = controllers.split(' ').collect();
+
+        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
+    }
+
+    fn root_control_group(&self) -> Cgroup {
+        let b: &Hierarchy = self as &Hierarchy;
+        Cgroup::load(Box::new(&*b), "".to_string())
+    }
+
+    fn check_support(&self, _sub: Controllers) -> bool {
+        return false;
+    }
+
+    fn root(&self) -> PathBuf {
+        PathBuf::from(self.root.clone())
+    }
+}
+
 impl V1 {
     /// Finds where control groups are mounted to and returns a hierarchy in which control groups
     /// can be created.
-    pub fn new() -> Self {
+    pub fn new() -> V1 {
         let mount_point = find_v1_mount().unwrap();
         V1 {
             mount_point: mount_point,
@@ -115,6 +206,60 @@ impl V1 {
     }
 }
 
+impl V2 {
+    /// Finds where control groups are mounted to and returns a hierarchy in which control groups
+    /// can be created.
+    pub fn new() -> V2 {
+        V2 {
+            root: String::from(UNIFIED_MOUNTPOINT),
+        }
+    }
+}
+
+pub const UNIFIED_MOUNTPOINT: &'static str = "/sys/fs/cgroup";
+
+#[cfg(all(target_os = "linux", not(target_env = "musl")))]
+pub fn is_cgroup2_unified_mode() -> bool {
+    let path = Path::new(UNIFIED_MOUNTPOINT);
+    let fs_stat = statfs::statfs(path);
+    if fs_stat.is_err() {
+        return false;
+    }
+
+    // FIXME notwork, nix will not compile CGROUP2_SUPER_MAGIC because not(target_env = "musl")
+    fs_stat.unwrap().filesystem_type() == statfs::CGROUP2_SUPER_MAGIC
+}
+
+pub const INIT_CGROUP_PATHS: &'static str = "/proc/1/cgroup";
+
+#[cfg(all(target_os = "linux", target_env = "musl"))]
+pub fn is_cgroup2_unified_mode() -> bool {
+    let lines = fs::read_to_string(INIT_CGROUP_PATHS);
+    if lines.is_err() {
+        return false;
+    }
+
+    for line in lines.unwrap().lines() {
+        let fields: Vec<&str> = line.split(':').collect();
+        if fields.len() != 3 {
+            continue;
+        }
+        if fields[0] != "0" {
+            return false;
+        }
+    }
+
+    true
+}
+
+pub fn auto() -> Box<dyn Hierarchy> {
+    if is_cgroup2_unified_mode() {
+        Box::new(V2::new())
+    } else {
+        Box::new(V1::new())
+    }
+}
+
 fn find_v1_mount() -> Option<String> {
     // Open mountinfo so we can get a parseable mount list
     let mountinfo_path = Path::new("/proc/self/mountinfo");
@@ -130,12 +275,22 @@ fn find_v1_mount() -> Option<String> {
         let line = _line.unwrap();
         let mut fields = line.split_whitespace();
         let index = line.find(" - ").unwrap();
-        let mut more_fields = line[index + 3..].split_whitespace().collect::<Vec<_>>();
-        let fstype = more_fields[0];
-        if fstype == "tmpfs" && more_fields[2].contains("ro") {
+        let more_fields = line[index + 3..].split_whitespace().collect::<Vec<_>>();
+        if more_fields.len() == 0 {
+            continue;
+        }
+        if more_fields[0] == "cgroup" {
+            if more_fields.len() < 3 {
+                continue;
+            }
             let cgroups_mount = fields.nth(4).unwrap();
-            info!("found cgroups at {:?}", cgroups_mount);
-            return Some(cgroups_mount.to_string());
+            if let Some(parent) = std::path::Path::new(cgroups_mount).parent() {
+                if let Some(path) = parent.as_os_str().to_str() {
+                    debug!("found cgroups {:?} from {:?}", path, cgroups_mount);
+                    return Some(path.to_string());
+                }
+            }
+            continue;
         }
     }
 
diff --git a/src/hugetlb.rs b/src/hugetlb.rs
index 7269b30..4237c11 100644
--- a/src/hugetlb.rs
+++ b/src/hugetlb.rs
@@ -1,4 +1,5 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 Ant Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
@@ -11,12 +12,12 @@ use std::fs::File;
 use std::io::{Read, Write};
 use std::path::PathBuf;
 
-use crate::error::*;
 use crate::error::ErrorKind::*;
+use crate::error::*;
+use crate::flat_keyed_to_vec;
 
 use crate::{
-    ControllIdentifier, ControllerInternal, Controllers, HugePageResources, Resources,
-    Subsystem,
+    ControllIdentifier, ControllerInternal, Controllers, HugePageResources, Resources, Subsystem,
 };
 
 /// A controller that allows controlling the `hugetlb` subsystem of a Cgroup.
@@ -27,6 +28,8 @@ use crate::{
 pub struct HugeTlbController {
     base: PathBuf,
     path: PathBuf,
+    sizes: Vec<String>,
+    v2: bool,
 }
 
 impl ControllerInternal for HugeTlbController {
@@ -43,6 +46,10 @@ impl ControllerInternal for HugeTlbController {
         &self.base
     }
 
+    fn is_v2(&self) -> bool {
+        self.v2
+    }
+
     fn apply(&self, res: &Resources) -> Result<()> {
         // get the resources that apply to this controller
         let res: &HugePageResources = &res.hugepages;
@@ -82,30 +89,63 @@ impl<'a> From<&'a Subsystem> for &'a HugeTlbController {
 fn read_u64_from(mut file: File) -> Result<u64> {
     let mut string = String::new();
     match file.read_to_string(&mut string) {
-        Ok(_) => string.trim().parse().map_err(|e| Error::with_cause(ParseError, e)),
+        Ok(_) => string
+            .trim()
+            .parse()
+            .map_err(|e| Error::with_cause(ParseError, e)),
         Err(e) => Err(Error::with_cause(ReadFailed, e)),
     }
 }
 
 impl HugeTlbController {
     /// Constructs a new `HugeTlbController` with `oroot` serving as the root of the control group.
-    pub fn new(oroot: PathBuf) -> Self {
+    pub fn new(oroot: PathBuf, v2: bool) -> Self {
         let mut root = oroot;
-        root.push(Self::controller_type().to_string());
+        if !v2 {
+            root.push(Self::controller_type().to_string());
+        }
+        let sizes = get_hugepage_sizes().unwrap();
         Self {
             base: root.clone(),
             path: root,
+            sizes: sizes,
+            v2: v2,
         }
     }
 
     /// Whether the system supports `hugetlb_size` hugepages.
-    pub fn size_supported(&self, _hugetlb_size: &str) -> bool {
-        // TODO
-        true
+    pub fn size_supported(&self, hugetlb_size: &str) -> bool {
+        for s in &self.sizes {
+            if s == hugetlb_size {
+                return true;
+            }
+        }
+        false
+    }
+
+    pub fn get_sizes(&self) -> Vec<String> {
+        self.sizes.clone()
+    }
+
+    fn failcnt_v2(&self, hugetlb_size: &str) -> Result<u64> {
+        self.open_path(&format!("hugetlb.{}.events", hugetlb_size), false)
+            .and_then(flat_keyed_to_vec)
+            .and_then(|x| {
+                if x.len() == 0 {
+                    return Err(Error::from_string(format!(
+                        "get empty from hugetlb.{}.events",
+                        hugetlb_size
+                    )));
+                }
+                Ok(x[0].1 as u64)
+            })
     }
 
     /// Check how many times has the limit of `hugetlb_size` hugepages been hit.
     pub fn failcnt(&self, hugetlb_size: &str) -> Result<u64> {
+        if self.v2 {
+            return self.failcnt_v2(hugetlb_size);
+        }
         self.open_path(&format!("hugetlb.{}.failcnt", hugetlb_size), false)
             .and_then(read_u64_from)
     }
@@ -120,8 +160,11 @@ impl HugeTlbController {
     /// Get the current usage of memory that is backed by hugepages of a certain size
     /// (`hugetlb_size`).
     pub fn usage_in_bytes(&self, hugetlb_size: &str) -> Result<u64> {
-        self.open_path(&format!("hugetlb.{}.usage_in_bytes", hugetlb_size), false)
-            .and_then(read_u64_from)
+        let mut file = format!("hugetlb.{}.usage_in_bytes", hugetlb_size);
+        if self.v2 {
+            file = format!("hugetlb.{}.current", hugetlb_size);
+        }
+        self.open_path(&file, false).and_then(read_u64_from)
     }
 
     /// Get the maximum observed usage of memory that is backed by hugepages of a certain size
@@ -130,16 +173,139 @@ impl HugeTlbController {
         self.open_path(
             &format!("hugetlb.{}.max_usage_in_bytes", hugetlb_size),
             false,
-        ).and_then(read_u64_from)
+        )
+        .and_then(read_u64_from)
     }
 
     /// Set the limit (in bytes) of how much memory can be backed by hugepages of a certain size
     /// (`hugetlb_size`).
     pub fn set_limit_in_bytes(&self, hugetlb_size: &str, limit: u64) -> Result<()> {
-        self.open_path(&format!("hugetlb.{}.limit_in_bytes", hugetlb_size), true)
-            .and_then(|mut file| {
-                file.write_all(limit.to_string().as_ref())
-                    .map_err(|e| Error::with_cause(WriteFailed, e))
-            })
+        let mut file = format!("hugetlb.{}.limit_in_bytes", hugetlb_size);
+        if self.v2 {
+            file = format!("hugetlb.{}.max", hugetlb_size);
+        }
+        self.open_path(&file, true).and_then(|mut file| {
+            file.write_all(limit.to_string().as_ref())
+                .map_err(|e| Error::with_cause(WriteFailed, e))
+        })
     }
 }
+
+pub const HUGEPAGESIZE_DIR: &'static str = "/sys/kernel/mm/hugepages";
+use regex::Regex;
+use std::collections::HashMap;
+use std::fs;
+
+fn get_hugepage_sizes() -> Result<Vec<String>> {
+    let mut m = Vec::new();
+    let dirs = fs::read_dir(HUGEPAGESIZE_DIR);
+    if dirs.is_err() {
+        return Ok(m);
+    }
+
+    for e in dirs.unwrap() {
+        let entry = e.unwrap();
+        let name = entry.file_name().into_string().unwrap();
+        let parts: Vec<&str> = name.split('-').collect();
+        if parts.len() != 2 {
+            continue;
+        }
+        let bmap = get_binary_size_map();
+        let size = parse_size(parts[1], &bmap)?;
+        let dabbrs = get_decimal_abbrs();
+        m.push(custom_size(size as f64, 1024.0, &dabbrs));
+    }
+
+    Ok(m)
+}
+
+pub const KB: u128 = 1000;
+pub const MB: u128 = 1000 * KB;
+pub const GB: u128 = 1000 * MB;
+pub const TB: u128 = 1000 * GB;
+pub const PB: u128 = 1000 * TB;
+
+pub const KiB: u128 = 1024;
+pub const MiB: u128 = 1024 * KiB;
+pub const GiB: u128 = 1024 * MiB;
+pub const TiB: u128 = 1024 * GiB;
+pub const PiB: u128 = 1024 * TiB;
+
+pub fn get_binary_size_map() -> HashMap<String, u128> {
+    let mut m = HashMap::new();
+    m.insert("k".to_string(), KiB);
+    m.insert("m".to_string(), MiB);
+    m.insert("g".to_string(), GiB);
+    m.insert("t".to_string(), TiB);
+    m.insert("p".to_string(), PiB);
+    m
+}
+
+pub fn get_decimal_size_map() -> HashMap<String, u128> {
+    let mut m = HashMap::new();
+    m.insert("k".to_string(), KB);
+    m.insert("m".to_string(), MB);
+    m.insert("g".to_string(), GB);
+    m.insert("t".to_string(), TB);
+    m.insert("p".to_string(), PB);
+    m
+}
+
+pub fn get_decimal_abbrs() -> Vec<String> {
+    let m = vec![
+        "B".to_string(),
+        "KB".to_string(),
+        "MB".to_string(),
+        "GB".to_string(),
+        "TB".to_string(),
+        "PB".to_string(),
+        "EB".to_string(),
+        "ZB".to_string(),
+        "YB".to_string(),
+    ];
+    m
+}
+
+fn parse_size(s: &str, m: &HashMap<String, u128>) -> Result<u128> {
+    let re = Regex::new(r"(?P<num>\d+)(?P<mul>[kKmMgGtTpP]?)[bB]?$");
+
+    if re.is_err() {
+        return Err(Error::new(InvalidBytesSize));
+    }
+    let caps = re.unwrap().captures(s).unwrap();
+
+    let num = caps.name("num");
+    let size: u128 = if num.is_some() {
+        let n = num.unwrap().as_str().trim().parse::<u128>();
+        if n.is_err() {
+            return Err(Error::new(InvalidBytesSize));
+        }
+        n.unwrap()
+    } else {
+        return Err(Error::new(InvalidBytesSize));
+    };
+
+    let q = caps.name("mul");
+    let mul: u128 = if q.is_some() {
+        let t = m.get(q.unwrap().as_str());
+        if t.is_some() {
+            *t.unwrap()
+        } else {
+            return Err(Error::new(InvalidBytesSize));
+        }
+    } else {
+        return Err(Error::new(InvalidBytesSize));
+    };
+
+    Ok(size * mul)
+}
+
+fn custom_size(mut size: f64, base: f64, m: &Vec<String>) -> String {
+    let mut i = 0;
+    while size >= base && i < m.len() - 1 {
+        size /= base;
+        i += 1;
+    }
+
+    format!("{}{}", size, m[i].as_str())
+}
diff --git a/src/lib.rs b/src/lib.rs
index 15c4cee..e48b9d4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,21 +1,25 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 Ant Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
 
 use log::*;
 
+use std::collections::HashMap;
 use std::fs::File;
-use std::io::{BufRead, BufReader, Write};
+use std::io::{BufRead, BufReader, Read, Write};
 use std::path::{Path, PathBuf};
 
 pub mod blkio;
 pub mod cgroup;
+pub mod cgroup_builder;
 pub mod cpu;
 pub mod cpuacct;
 pub mod cpuset;
 pub mod devices;
 pub mod error;
+pub mod events;
 pub mod freezer;
 pub mod hierarchies;
 pub mod hugetlb;
@@ -25,13 +29,14 @@ pub mod net_prio;
 pub mod perf_event;
 pub mod pid;
 pub mod rdma;
-pub mod cgroup_builder;
+pub mod systemd;
 
 use crate::blkio::BlkIoController;
 use crate::cpu::CpuController;
 use crate::cpuacct::CpuAcctController;
 use crate::cpuset::CpuSetController;
 use crate::devices::DevicesController;
+use crate::error::ErrorKind::*;
 use crate::error::*;
 use crate::freezer::FreezerController;
 use crate::hugetlb::HugeTlbController;
@@ -41,6 +46,7 @@ use crate::net_prio::NetPrioController;
 use crate::perf_event::PerfEventController;
 use crate::pid::PidController;
 use crate::rdma::RdmaController;
+use crate::systemd::SystemdController;
 
 pub use crate::cgroup::Cgroup;
 
@@ -73,6 +79,8 @@ pub enum Subsystem {
     HugeTlb(HugeTlbController),
     /// Controller for the `Rdma` subsystem, see `RdmaController` for more information.
     Rdma(RdmaController),
+    /// Controller for the `Systemd` subsystem, see `SystemdController` for more information.
+    Systemd(SystemdController),
 }
 
 #[doc(hidden)]
@@ -91,6 +99,7 @@ pub enum Controllers {
     NetPrio,
     HugeTlb,
     Rdma,
+    Systemd,
 }
 
 impl Controllers {
@@ -109,6 +118,7 @@ impl Controllers {
             Controllers::NetPrio => return "net_prio".to_string(),
             Controllers::HugeTlb => return "hugetlb".to_string(),
             Controllers::Rdma => return "rdma".to_string(),
+            Controllers::Systemd => return "systemd".to_string(),
         }
     }
 }
@@ -125,6 +135,13 @@ mod sealed {
         fn get_path_mut(&mut self) -> &mut PathBuf;
         fn get_base(&self) -> &PathBuf;
 
+        /// Hooks running after controller crated, if have
+        fn post_create(&self) {}
+
+        fn is_v2(&self) -> bool {
+            false
+        }
+
         fn verify_path(&self) -> Result<()> {
             if self.get_path().starts_with(self.get_base()) {
                 Ok(())
@@ -152,6 +169,17 @@ mod sealed {
             }
         }
 
+        fn get_max_value(&self, f: &str) -> Result<MaxValue> {
+            self.open_path(f, false).and_then(|mut file| {
+                let mut string = String::new();
+                let res = file.read_to_string(&mut string);
+                match res {
+                    Ok(_) => parse_max_value(&string),
+                    Err(e) => Err(Error::with_cause(ReadFailed, e)),
+                }
+            })
+        }
+
         #[doc(hidden)]
         fn path_exists(&self, p: &str) -> bool {
             if let Err(_) = self.verify_path() {
@@ -160,7 +188,6 @@ mod sealed {
 
             std::path::Path::new(p).exists()
         }
-
     }
 }
 
@@ -194,9 +221,14 @@ pub trait Controller {
 
     /// Get the list of tasks that this controller has.
     fn tasks(&self) -> Vec<CgroupPid>;
+
+    fn v2(&self) -> bool;
 }
 
-impl<T> Controller for T where T: ControllerInternal {
+impl<T> Controller for T
+where
+    T: ControllerInternal,
+{
     fn control_type(&self) -> Controllers {
         ControllerInternal::control_type(self)
     }
@@ -213,10 +245,11 @@ impl<T> Controller for T where T: ControllerInternal {
 
     /// Create this controller
     fn create(&self) {
-        self.verify_path().expect("path should be valid");
+        self.verify_path()
+            .expect(format!("path should be valid: {:?}", self.path()).as_str());
 
-        match ::std::fs::create_dir(self.get_path()) {
-            Ok(_) => (),
+        match ::std::fs::create_dir_all(self.get_path()) {
+            Ok(_) => self.post_create(),
             Err(e) => warn!("error create_dir {:?}", e),
         }
     }
@@ -229,13 +262,17 @@ impl<T> Controller for T where T: ControllerInternal {
     /// Delete the controller.
     fn delete(&self) {
         if self.get_path().exists() {
-            let _ = ::std::fs::remove_dir(self.get_path());
+            libc_rmdir(self.get_path().to_str().unwrap());
         }
     }
 
     /// Attach a task to this controller.
     fn add_task(&self, pid: &CgroupPid) -> Result<()> {
-        self.open_path("tasks", true).and_then(|mut file| {
+        let mut file = "tasks";
+        if self.is_v2() {
+            file = "cgroup.procs";
+        }
+        self.open_path(file, true).and_then(|mut file| {
             file.write_all(pid.pid.to_string().as_ref())
                 .map_err(|e| Error::with_cause(ErrorKind::WriteFailed, e))
         })
@@ -243,7 +280,11 @@ impl<T> Controller for T where T: ControllerInternal {
 
     /// Get the list of tasks that this controller has.
     fn tasks(&self) -> Vec<CgroupPid> {
-        self.open_path("tasks", false)
+        let mut file = "tasks";
+        if self.is_v2() {
+            file = "cgroup.procs";
+        }
+        self.open_path(file, false)
             .and_then(|file| {
                 let bf = BufReader::new(file);
                 let mut v = Vec::new();
@@ -254,7 +295,12 @@ impl<T> Controller for T where T: ControllerInternal {
                     }
                 }
                 Ok(v.into_iter().map(CgroupPid::from).collect())
-            }).unwrap_or(vec![])
+            })
+            .unwrap_or(vec![])
+    }
+
+    fn v2(&self) -> bool {
+        self.is_v2()
     }
 }
 
@@ -275,6 +321,8 @@ pub trait Hierarchy {
     /// Return a handle to the root control group in the hierarchy.
     fn root_control_group(&self) -> Cgroup;
 
+    fn v2(&self) -> bool;
+
     /// Checks whether a certain subsystem is supported in the hierarchy.
     ///
     /// This is an internal function and should not be used.
@@ -288,16 +336,16 @@ pub struct MemoryResources {
     /// Whether values should be applied to the controller.
     pub update_values: bool,
     /// How much memory (in bytes) can the kernel consume.
-    pub kernel_memory_limit: u64,
+    pub kernel_memory_limit: i64,
     /// Upper limit of memory usage of the control group's tasks.
-    pub memory_hard_limit: u64,
+    pub memory_hard_limit: i64,
     /// How much memory the tasks in the control group can use when the system is under memory
     /// pressure.
-    pub memory_soft_limit: u64,
+    pub memory_soft_limit: i64,
     /// How much of the kernel's memory (in bytes) can be used for TCP-related buffers.
-    pub kernel_tcp_memory_limit: u64,
+    pub kernel_tcp_memory_limit: i64,
     /// How much memory and swap together can the tasks in the control group use.
-    pub memory_swap_limit: u64,
+    pub memory_swap_limit: i64,
     /// Controls the tendency of the kernel to swap out parts of the address space of the tasks to
     /// disk. Lower value implies less likely.
     ///
@@ -316,7 +364,7 @@ pub struct PidResources {
     /// Note that attaching processes to the control group will still succeed _even_ if the limit
     /// would be violated, however forks/clones inside the control group will have with `EAGAIN` if
     /// they would violate the limit set here.
-    pub maximum_number_of_processes: pid::PidMax,
+    pub maximum_number_of_processes: MaxValue,
 }
 
 /// Resources limits about how the tasks can use the CPU.
@@ -327,7 +375,7 @@ pub struct CpuResources {
     // cpuset
     /// A comma-separated list of CPU IDs where the task in the control group can run. Dashes
     /// between numbers indicate ranges.
-    pub cpus: String,
+    pub cpus: Option<String>,
     /// Same syntax as the `cpus` field of this structure, but applies to memory nodes instead of
     /// processors.
     pub mems: String,
@@ -419,9 +467,9 @@ pub struct BlkIoDeviceResource {
     /// The minor number of the device.
     pub minor: u64,
     /// The weight of the device against the descendant nodes.
-    pub weight: u16,
+    pub weight: Option<u16>,
     /// The weight of the device against the sibling nodes.
-    pub leaf_weight: u16,
+    pub leaf_weight: Option<u16>,
 }
 
 /// Provides the ability to throttle a device (both byte/sec, and IO op/s)
@@ -441,9 +489,9 @@ pub struct BlkIoResources {
     /// Whether values should be applied to the controller.
     pub update_values: bool,
     /// The weight of the control group against descendant nodes.
-    pub weight: u16,
+    pub weight: Option<u16>,
     /// The weight of the control group against sibling nodes.
-    pub leaf_weight: u16,
+    pub leaf_weight: Option<u16>,
     /// For each device, a separate weight (both normal and leaf) can be provided.
     pub weight_device: Vec<BlkIoDeviceResource>,
     /// Throttled read bytes/second can be provided for each device.
@@ -563,6 +611,11 @@ impl Subsystem {
                 c.get_path_mut().push(path);
                 c
             }),
+            Subsystem::Systemd(cont) => Subsystem::Systemd({
+                let mut c = cont.clone();
+                c.get_path_mut().push(path);
+                c
+            }),
         }
     }
 
@@ -581,6 +634,137 @@ impl Subsystem {
             Subsystem::NetPrio(cont) => cont,
             Subsystem::HugeTlb(cont) => cont,
             Subsystem::Rdma(cont) => cont,
+            Subsystem::Systemd(cont) => cont,
+        }
+    }
+
+    fn controller_name(&self) -> String {
+        self.to_controller().control_type().to_string()
+    }
+}
+
+/// The values for `memory.hight` or `pids.max`
+#[derive(Eq, PartialEq, Copy, Clone, Debug)]
+pub enum MaxValue {
+    /// This value is returned when the text is `"max"`.
+    Max,
+    /// When the value is a numerical value, they are returned via this enum field.
+    Value(i64),
+}
+
+impl Default for MaxValue {
+    fn default() -> Self {
+        MaxValue::Max
+    }
+}
+
+impl MaxValue {
+    fn to_i64(&self) -> i64 {
+        match self {
+            MaxValue::Max => -1,
+            MaxValue::Value(num) => *num,
+        }
+    }
+
+    fn to_string(&self) -> String {
+        match self {
+            MaxValue::Max => "max".to_string(),
+            MaxValue::Value(num) => num.to_string(),
         }
     }
 }
+
+pub fn parse_max_value(s: &String) -> Result<MaxValue> {
+    if s.trim() == "max" {
+        return Ok(MaxValue::Max);
+    }
+    match s.trim().parse() {
+        Ok(val) => Ok(MaxValue::Value(val)),
+        Err(e) => Err(Error::with_cause(ParseError, e)),
+    }
+}
+
+// Flat keyed
+//  KEY0 VAL0\n
+//  KEY1 VAL1\n
+pub fn flat_keyed_to_vec(mut file: File) -> Result<Vec<(String, i64)>> {
+    let mut content = String::new();
+    file.read_to_string(&mut content)
+        .map_err(|e| Error::with_cause(ReadFailed, e))?;
+
+    let mut v = Vec::new();
+    for line in content.lines() {
+        let parts: Vec<&str> = line.split(' ').collect();
+        if parts.len() == 2 {
+            match parts[1].parse::<i64>() {
+                Ok(i) => {
+                    v.push((parts[0].to_string(), i));
+                }
+                Err(_) => {}
+            }
+        }
+    }
+    Ok(v)
+}
+
+// Flat keyed
+//  KEY0 VAL0\n
+//  KEY1 VAL1\n
+pub fn flat_keyed_to_hashmap(mut file: File) -> Result<HashMap<String, i64>> {
+    let mut content = String::new();
+    file.read_to_string(&mut content)
+        .map_err(|e| Error::with_cause(ReadFailed, e))?;
+
+    let mut h = HashMap::new();
+    for line in content.lines() {
+        let parts: Vec<&str> = line.split(' ').collect();
+        if parts.len() == 2 {
+            match parts[1].parse::<i64>() {
+                Ok(i) => {
+                    h.insert(parts[0].to_string(), i);
+                }
+                Err(_) => {}
+            }
+        }
+    }
+    Ok(h)
+}
+
+// Nested keyed
+//  KEY0 SUB_KEY0=VAL00 SUB_KEY1=VAL01...
+//  KEY1 SUB_KEY0=VAL10 SUB_KEY1=VAL11...
+pub fn nested_keyed_to_hashmap(mut file: File) -> Result<HashMap<String, HashMap<String, i64>>> {
+    let mut content = String::new();
+    file.read_to_string(&mut content)
+        .map_err(|e| Error::with_cause(ReadFailed, e))?;
+
+    let mut h = HashMap::new();
+    for line in content.lines() {
+        let parts: Vec<&str> = line.split(' ').collect();
+        if parts.len() == 0 {
+            continue;
+        }
+        let mut th = HashMap::new();
+        for item in parts[1..].into_iter() {
+            let fields: Vec<&str> = item.split('=').collect();
+            if fields.len() == 2 {
+                match fields[1].parse::<i64>() {
+                    Ok(i) => {
+                        th.insert(fields[0].to_string(), i);
+                    }
+                    Err(_) => {}
+                }
+            }
+        }
+        h.insert(parts[0].to_string(), th);
+    }
+
+    Ok(h)
+}
+
+/// fs::remove_dir_all or fs::remove_dir can't work with cgroup directory sometimes.
+/// with error: `Os { code: 1, kind: PermissionDenied, message: "Operation not permitted" }`
+pub fn libc_rmdir(p: &str) {
+    // with int return value
+    let _ = unsafe { libc::rmdir(p.as_ptr() as *const i8) };
+}
diff --git a/src/memory.rs b/src/memory.rs
index 0e3e6fb..0f193f3 100644
--- a/src/memory.rs
+++ b/src/memory.rs
@@ -1,4 +1,5 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 Ant Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
@@ -7,15 +8,21 @@
 //!
 //! See the Kernel's documentation for more information about this subsystem, found at:
 //!  [Documentation/cgroup-v1/memory.txt](https://www.kernel.org/doc/Documentation/cgroup-v1/memory.txt)
+use std::collections::HashMap;
 use std::fs::File;
 use std::io::{Read, Write};
 use std::path::PathBuf;
+use std::sync::mpsc::Receiver;
 
-use crate::error::*;
 use crate::error::ErrorKind::*;
+use crate::error::*;
+use crate::events;
+
+use crate::flat_keyed_to_hashmap;
 
 use crate::{
-    ControllIdentifier, ControllerInternal, Controllers, MemoryResources, Resources, Subsystem,
+    ControllIdentifier, ControllerInternal, Controllers, MaxValue, MemoryResources, Resources,
+    Subsystem,
 };
 
 /// A controller that allows controlling the `memory` subsystem of a Cgroup.
@@ -27,6 +34,15 @@ use crate::{
 pub struct MemController {
     base: PathBuf,
     path: PathBuf,
+    v2: bool,
+}
+
+#[derive(Default, Debug, PartialEq, Eq)]
+pub struct SetMemory {
+    pub low: Option<MaxValue>,
+    pub high: Option<MaxValue>,
+    pub min: Option<MaxValue>,
+    pub max: Option<MaxValue>,
 }
 
 /// Controls statistics and controls about the OOM killer operating in this control group.
@@ -114,7 +130,8 @@ fn parse_numa_stat(s: String) -> Result<NumaStat> {
                     x.split("=").collect::<Vec<_>>()[1]
                         .parse::<u64>()
                         .unwrap_or(0)
-                }).collect()
+                })
+                .collect()
         },
         file_pages: file_line
             .split(|x| x == ' ' || x == '=')
@@ -128,7 +145,8 @@ fn parse_numa_stat(s: String) -> Result<NumaStat> {
                     x.split("=").collect::<Vec<_>>()[1]
                         .parse::<u64>()
                         .unwrap_or(0)
-                }).collect()
+                })
+                .collect()
         },
         anon_pages: anon_line
             .split(|x| x == ' ' || x == '=')
@@ -142,7 +160,8 @@ fn parse_numa_stat(s: String) -> Result<NumaStat> {
                     x.split("=").collect::<Vec<_>>()[1]
                         .parse::<u64>()
                         .unwrap_or(0)
-                }).collect()
+                })
+                .collect()
         },
         unevictable_pages: unevict_line
             .split(|x| x == ' ' || x == '=')
@@ -156,7 +175,8 @@ fn parse_numa_stat(s: String) -> Result<NumaStat> {
                     x.split("=").collect::<Vec<_>>()[1]
                         .parse::<u64>()
                         .unwrap_or(0)
-                }).collect()
+                })
+                .collect()
         },
         hierarchical_total_pages: hier_total_line
             .split(|x| x == ' ' || x == '=')
@@ -170,7 +190,8 @@ fn parse_numa_stat(s: String) -> Result<NumaStat> {
                     x.split("=").collect::<Vec<_>>()[1]
                         .parse::<u64>()
                         .unwrap_or(0)
-                }).collect()
+                })
+                .collect()
         },
         hierarchical_file_pages: hier_file_line
             .split(|x| x == ' ' || x == '=')
@@ -184,7 +205,8 @@ fn parse_numa_stat(s: String) -> Result<NumaStat> {
                     x.split("=").collect::<Vec<_>>()[1]
                         .parse::<u64>()
                         .unwrap_or(0)
-                }).collect()
+                })
+                .collect()
         },
         hierarchical_anon_pages: hier_anon_line
             .split(|x| x == ' ' || x == '=')
@@ -198,7 +220,8 @@ fn parse_numa_stat(s: String) -> Result<NumaStat> {
                     x.split("=").collect::<Vec<_>>()[1]
                         .parse::<u64>()
                         .unwrap_or(0)
-                }).collect()
+                })
+                .collect()
         },
         hierarchical_unevictable_pages: hier_unevict_line
             .split(|x| x == ' ' || x == '=')
@@ -212,7 +235,8 @@ fn parse_numa_stat(s: String) -> Result<NumaStat> {
                     x.split("=").collect::<Vec<_>>()[1]
                         .parse::<u64>()
                         .unwrap_or(0)
-                }).collect()
+                })
+                .collect()
         },
     })
 }
@@ -236,8 +260,8 @@ pub struct MemoryStat {
     pub inactive_file: u64,
     pub active_file: u64,
     pub unevictable: u64,
-    pub hierarchical_memory_limit: u64,
-    pub hierarchical_memsw_limit: u64,
+    pub hierarchical_memory_limit: i64,
+    pub hierarchical_memsw_limit: i64,
     pub total_cache: u64,
     pub total_rss: u64,
     pub total_rss_huge: u64,
@@ -255,52 +279,63 @@ pub struct MemoryStat {
     pub total_inactive_file: u64,
     pub total_active_file: u64,
     pub total_unevictable: u64,
+    pub raw: HashMap<String, u64>,
 }
 
 fn parse_memory_stat(s: String) -> Result<MemoryStat> {
-    let sp: Vec<&str> = s
-        .split_whitespace()
-        .filter(|x| x.parse::<u64>().is_ok())
-        .collect();
+    let mut raw = HashMap::new();
+
+    for l in s.lines() {
+        let t: Vec<&str> = l.split(' ').collect();
+        if t.len() != 2 {
+            continue;
+        }
+        let n = t[1].trim().parse::<u64>();
+        if n.is_err() {
+            continue;
+        }
+
+        raw.insert(t[0].to_string(), n.unwrap());
+    }
 
-    let mut spl = sp.iter();
     Ok(MemoryStat {
-        cache: spl.next().unwrap().parse::<u64>().unwrap(),
-        rss: spl.next().unwrap().parse::<u64>().unwrap(),
-        rss_huge: spl.next().unwrap().parse::<u64>().unwrap(),
-        shmem: spl.next().unwrap().parse::<u64>().unwrap(),
-        mapped_file: spl.next().unwrap().parse::<u64>().unwrap(),
-        dirty: spl.next().unwrap().parse::<u64>().unwrap(),
-        writeback: spl.next().unwrap().parse::<u64>().unwrap(),
-        swap: spl.next().unwrap().parse::<u64>().unwrap(),
-        pgpgin: spl.next().unwrap().parse::<u64>().unwrap(),
-        pgpgout: spl.next().unwrap().parse::<u64>().unwrap(),
-        pgfault: spl.next().unwrap().parse::<u64>().unwrap(),
-        pgmajfault: spl.next().unwrap().parse::<u64>().unwrap(),
-        inactive_anon: spl.next().unwrap().parse::<u64>().unwrap(),
-        active_anon: spl.next().unwrap().parse::<u64>().unwrap(),
-        inactive_file: spl.next().unwrap().parse::<u64>().unwrap(),
-        active_file: spl.next().unwrap().parse::<u64>().unwrap(),
-        unevictable: spl.next().unwrap().parse::<u64>().unwrap(),
-        hierarchical_memory_limit: spl.next().unwrap().parse::<u64>().unwrap(),
-        hierarchical_memsw_limit: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_cache: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_rss: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_rss_huge: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_shmem: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_mapped_file: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_dirty: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_writeback: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_swap: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_pgpgin: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_pgpgout: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_pgfault: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_pgmajfault: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_inactive_anon: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_active_anon: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_inactive_file: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_active_file: spl.next().unwrap().parse::<u64>().unwrap(),
-        total_unevictable: spl.next().unwrap().parse::<u64>().unwrap(),
+        cache: *raw.get("cache").unwrap_or(&0),
+        rss: *raw.get("rss").unwrap_or(&0),
+        rss_huge: *raw.get("rss_huge").unwrap_or(&0),
+        shmem: *raw.get("shmem").unwrap_or(&0),
+        mapped_file: *raw.get("mapped_file").unwrap_or(&0),
+        dirty: *raw.get("dirty").unwrap_or(&0),
+        writeback: *raw.get("writeback").unwrap_or(&0),
+        swap: *raw.get("swap").unwrap_or(&0),
+        pgpgin: *raw.get("pgpgin").unwrap_or(&0),
+        pgpgout: *raw.get("pgpgout").unwrap_or(&0),
+        pgfault: *raw.get("pgfault").unwrap_or(&0),
+        pgmajfault: *raw.get("pgmajfault").unwrap_or(&0),
+        inactive_anon: *raw.get("inactive_anon").unwrap_or(&0),
+        active_anon: *raw.get("active_anon").unwrap_or(&0),
+        inactive_file: *raw.get("inactive_file").unwrap_or(&0),
+        active_file: *raw.get("active_file").unwrap_or(&0),
+        unevictable: *raw.get("unevictable").unwrap_or(&0),
+        hierarchical_memory_limit: *raw.get("hierarchical_memory_limit").unwrap_or(&0) as i64,
+        hierarchical_memsw_limit: *raw.get("hierarchical_memsw_limit").unwrap_or(&0) as i64,
+        total_cache: *raw.get("total_cache").unwrap_or(&0),
+        total_rss: *raw.get("total_rss").unwrap_or(&0),
+        total_rss_huge: *raw.get("total_rss_huge").unwrap_or(&0),
+        total_shmem: *raw.get("total_shmem").unwrap_or(&0),
+        total_mapped_file: *raw.get("total_mapped_file").unwrap_or(&0),
+        total_dirty: *raw.get("total_dirty").unwrap_or(&0),
+        total_writeback: *raw.get("total_writeback").unwrap_or(&0),
+        total_swap: *raw.get("total_swap").unwrap_or(&0),
+        total_pgpgin: *raw.get("total_pgpgin").unwrap_or(&0),
+        total_pgpgout: *raw.get("total_pgpgout").unwrap_or(&0),
+        total_pgfault: *raw.get("total_pgfault").unwrap_or(&0),
+        total_pgmajfault: *raw.get("total_pgmajfault").unwrap_or(&0),
+        total_inactive_anon: *raw.get("total_inactive_anon").unwrap_or(&0),
+        total_active_anon: *raw.get("total_active_anon").unwrap_or(&0),
+        total_inactive_file: *raw.get("total_inactive_file").unwrap_or(&0),
+        total_active_file: *raw.get("total_active_file").unwrap_or(&0),
+        total_unevictable: *raw.get("total_unevictable").unwrap_or(&0),
+        raw: raw,
     })
 }
 
@@ -311,7 +346,7 @@ pub struct MemSwap {
     /// How many times the limit has been hit.
     pub fail_cnt: u64,
     /// Memory and swap usage limit in bytes.
-    pub limit_in_bytes: u64,
+    pub limit_in_bytes: i64,
     /// Current usage of memory and swap in bytes.
     pub usage_in_bytes: u64,
     /// The maximum observed usage of memory and swap in bytes.
@@ -325,7 +360,7 @@ pub struct Memory {
     /// How many times the limit has been hit.
     pub fail_cnt: u64,
     /// The limit in bytes of the memory usage of the control group's tasks.
-    pub limit_in_bytes: u64,
+    pub limit_in_bytes: i64,
     /// The current usage of memory by the control group's tasks.
     pub usage_in_bytes: u64,
     /// The maximum observed usage of memory by the control group's tasks.
@@ -347,7 +382,7 @@ pub struct Memory {
     pub oom_control: OomControl,
     /// Allows setting a limit to memory usage which is enforced when the system (note, _not_ the
     /// control group) detects memory pressure.
-    pub soft_limit_in_bytes: u64,
+    pub soft_limit_in_bytes: i64,
     /// Contains a wide array of statistics about the memory usage of the tasks in the control
     /// group.
     pub stat: MemoryStat,
@@ -370,7 +405,7 @@ pub struct Tcp {
     pub fail_cnt: u64,
     /// The limit in bytes of the memory usage of the kernel's TCP buffers by control group's
     /// tasks.
-    pub limit_in_bytes: u64,
+    pub limit_in_bytes: i64,
     /// The current memory used by the kernel's TCP buffers related to these tasks.
     pub usage_in_bytes: u64,
     /// The observed maximum usage of memory by the kernel's TCP buffers (that originated from
@@ -387,7 +422,7 @@ pub struct Kmem {
     /// How many times the limit has been hit.
     pub fail_cnt: u64,
     /// The limit in bytes of the kernel memory used by the control group's tasks.
-    pub limit_in_bytes: u64,
+    pub limit_in_bytes: i64,
     /// The current usage of kernel memory used by the control group's tasks, in bytes.
     pub usage_in_bytes: u64,
     /// The maximum observed usage of kernel memory used by the control group's tasks, in bytes.
@@ -410,6 +445,10 @@ impl ControllerInternal for MemController {
         &self.base
     }
 
+    fn is_v2(&self) -> bool {
+        self.v2
+    }
+
     fn apply(&self, res: &Resources) -> Result<()> {
         // get the resources that apply to this controller
         let memres: &MemoryResources = &res.memory;
@@ -429,12 +468,76 @@ impl ControllerInternal for MemController {
 
 impl MemController {
     /// Contructs a new `MemController` with `oroot` serving as the root of the control group.
-    pub fn new(oroot: PathBuf) -> Self {
+    pub fn new(oroot: PathBuf, v2: bool) -> Self {
         let mut root = oroot;
-        root.push(Self::controller_type().to_string());
+        if !v2 {
+            root.push(Self::controller_type().to_string());
+        }
         Self {
             base: root.clone(),
             path: root,
+            v2: v2,
+        }
+    }
+
+    // for v2
+    pub fn set_mem(&self, m: SetMemory) -> Result<()> {
+        let values = vec![
+            (m.high, "memory.high"),
+            (m.low, "memory.low"),
+            (m.max, "memory.max"),
+            (m.min, "memory.min"),
+        ];
+        for value in values {
+            let v = value.0;
+            let f = value.1;
+            if v.is_some() {
+                let v = v.unwrap().to_string();
+                self.open_path(f, true).and_then(|mut file| {
+                    file.write_all(v.as_ref())
+                        .map_err(|e| Error::with_cause(WriteFailed, e))
+                })?;
+            }
+        }
+        Ok(())
+    }
+
+    // for v2
+    pub fn get_mem(&self) -> Result<SetMemory> {
+        let mut m: SetMemory = Default::default();
+        self.get_max_value("memory.high").map(|x| m.high = Some(x));
+        self.get_max_value("memory.low").map(|x| m.low = Some(x));
+        self.get_max_value("memory.max").map(|x| m.max = Some(x));
+        self.get_max_value("memory.min").map(|x| m.min = Some(x));
+
+        Ok(m)
+    }
+
+    fn memory_stat_v2(&self) -> Memory {
+        let set = self.get_mem().unwrap();
+
+        Memory {
+            fail_cnt: 0,
+            limit_in_bytes: set.max.unwrap().to_i64(),
+            usage_in_bytes: self
+                .open_path("memory.current", false)
+                .and_then(read_u64_from)
+                .unwrap_or(0),
+            max_usage_in_bytes: 0,
+            move_charge_at_immigrate: 0,
+            numa_stat: NumaStat::default(),
+            oom_control: OomControl::default(),
+            soft_limit_in_bytes: set.low.unwrap().to_i64(),
+            stat: self
+                .open_path("memory.stat", false)
+                .and_then(read_string_from)
+                .and_then(parse_memory_stat)
+                .unwrap_or(MemoryStat::default()),
+            swappiness: self
+                .open_path("memory.swap.current", false)
+                .and_then(read_u64_from)
+                .unwrap_or(0),
+            use_hierarchy: 0,
         }
     }
 
@@ -444,6 +547,10 @@ impl MemController {
     /// See the individual fields for more explanation, and as always, remember to consult the
     /// kernel Documentation and/or sources.
     pub fn memory_stat(&self) -> Memory {
+        if self.v2 {
+            return self.memory_stat_v2();
+        }
+
         Memory {
             fail_cnt: self
                 .open_path("memory.failcnt", false)
@@ -451,7 +558,7 @@ impl MemController {
                 .unwrap_or(0),
             limit_in_bytes: self
                 .open_path("memory.limit_in_bytes", false)
-                .and_then(read_u64_from)
+                .and_then(read_i64_from)
                 .unwrap_or(0),
             usage_in_bytes: self
                 .open_path("memory.usage_in_bytes", false)
@@ -477,7 +584,7 @@ impl MemController {
                 .unwrap_or(OomControl::default()),
             soft_limit_in_bytes: self
                 .open_path("memory.soft_limit_in_bytes", false)
-                .and_then(read_u64_from)
+                .and_then(read_i64_from)
                 .unwrap_or(0),
             stat: self
                 .open_path("memory.stat", false)
@@ -504,8 +611,8 @@ impl MemController {
                 .unwrap_or(0),
             limit_in_bytes: self
                 .open_path("memory.kmem.limit_in_bytes", false)
-                .and_then(read_u64_from)
-                .unwrap_or(0),
+                .and_then(read_i64_from)
+                .unwrap_or(-1),
             usage_in_bytes: self
                 .open_path("memory.kmem.usage_in_bytes", false)
                 .and_then(read_u64_from)
@@ -531,7 +638,7 @@ impl MemController {
                 .unwrap_or(0),
             limit_in_bytes: self
                 .open_path("memory.kmem.tcp.limit_in_bytes", false)
-                .and_then(read_u64_from)
+                .and_then(read_i64_from)
                 .unwrap_or(0),
             usage_in_bytes: self
                 .open_path("memory.kmem.tcp.usage_in_bytes", false)
@@ -544,9 +651,32 @@ impl MemController {
         }
     }
 
+    pub fn memswap_v2(&self) -> MemSwap {
+        MemSwap {
+            fail_cnt: self
+                .open_path("memory.swap.events", false)
+                .and_then(flat_keyed_to_hashmap)
+                .and_then(|x| Ok(*x.get("fail").unwrap_or(&0) as u64))
+                .unwrap(),
+            limit_in_bytes: self
+                .open_path("memory.swap.max", false)
+                .and_then(read_i64_from)
+                .unwrap_or(0),
+            usage_in_bytes: self
+                .open_path("memory.swap.current", false)
+                .and_then(read_u64_from)
+                .unwrap_or(0),
+            max_usage_in_bytes: 0,
+        }
+    }
+
     /// Gathers information about the memory usage of the control group including the swap usage
     /// (if any).
     pub fn memswap(&self) -> MemSwap {
+        if self.v2 {
+            return self.memswap_v2();
+        }
+
         MemSwap {
             fail_cnt: self
                 .open_path("memory.memsw.failcnt", false)
@@ -554,7 +684,7 @@ impl MemController {
                 .unwrap_or(0),
             limit_in_bytes: self
                 .open_path("memory.memsw.limit_in_bytes", false)
-                .and_then(read_u64_from)
+                .and_then(read_i64_from)
                 .unwrap_or(0),
             usage_in_bytes: self
                 .open_path("memory.memsw.usage_in_bytes", false)
@@ -569,11 +699,10 @@ impl MemController {
 
     /// Reset the fail counter
     pub fn reset_fail_count(&self) -> Result<()> {
-        self.open_path("memory.failcnt", true)
-            .and_then(|mut file| {
-                file.write_all("0".to_string().as_ref())
-                    .map_err(|e| Error::with_cause(WriteFailed, e))
-            })
+        self.open_path("memory.failcnt", true).and_then(|mut file| {
+            file.write_all("0".to_string().as_ref())
+                .map_err(|e| Error::with_cause(WriteFailed, e))
+        })
     }
 
     /// Reset the kernel memory fail counter
@@ -604,16 +733,19 @@ impl MemController {
     }
 
     /// Set the memory usage limit of the control group, in bytes.
-    pub fn set_limit(&self, limit: u64) -> Result<()> {
-        self.open_path("memory.limit_in_bytes", true)
-            .and_then(|mut file| {
-                file.write_all(limit.to_string().as_ref())
-                    .map_err(|e| Error::with_cause(WriteFailed, e))
-            })
+    pub fn set_limit(&self, limit: i64) -> Result<()> {
+        let mut file = "memory.limit_in_bytes";
+        if self.v2 {
+            file = "memory.max";
+        }
+        self.open_path(file, true).and_then(|mut file| {
+            file.write_all(limit.to_string().as_ref())
+                .map_err(|e| Error::with_cause(WriteFailed, e))
+        })
     }
 
     /// Set the kernel memory limit of the control group, in bytes.
-    pub fn set_kmem_limit(&self, limit: u64) -> Result<()> {
+    pub fn set_kmem_limit(&self, limit: i64) -> Result<()> {
         self.open_path("memory.kmem.limit_in_bytes", true)
             .and_then(|mut file| {
                 file.write_all(limit.to_string().as_ref())
@@ -622,16 +754,19 @@ impl MemController {
     }
 
     /// Set the memory+swap limit of the control group, in bytes.
-    pub fn set_memswap_limit(&self, limit: u64) -> Result<()> {
-        self.open_path("memory.memsw.limit_in_bytes", true)
-            .and_then(|mut file| {
-                file.write_all(limit.to_string().as_ref())
-                    .map_err(|e| Error::with_cause(WriteFailed, e))
-            })
+    pub fn set_memswap_limit(&self, limit: i64) -> Result<()> {
+        let mut file = "memory.memsw.limit_in_bytes";
+        if self.v2 {
+            file = "memory.swap.max";
+        }
+        self.open_path(file, true).and_then(|mut file| {
+            file.write_all(limit.to_string().as_ref())
+                .map_err(|e| Error::with_cause(WriteFailed, e))
+        })
     }
 
     /// Set how much kernel memory can be used for TCP-related buffers by the control group.
-    pub fn set_tcp_limit(&self, limit: u64) -> Result<()> {
+    pub fn set_tcp_limit(&self, limit: i64) -> Result<()> {
         self.open_path("memory.kmem.tcp.limit_in_bytes", true)
             .and_then(|mut file| {
                 file.write_all(limit.to_string().as_ref())
@@ -643,12 +778,15 @@ impl MemController {
     ///
     /// This limit is enforced when the system is nearing OOM conditions. Contrast this with the
     /// hard limit, which is _always_ enforced.
-    pub fn set_soft_limit(&self, limit: u64) -> Result<()> {
-        self.open_path("memory.soft_limit_in_bytes", true)
-            .and_then(|mut file| {
-                file.write_all(limit.to_string().as_ref())
-                    .map_err(|e| Error::with_cause(WriteFailed, e))
-            })
+    pub fn set_soft_limit(&self, limit: i64) -> Result<()> {
+        let mut file = "memory.soft_limit_in_bytes";
+        if self.v2 {
+            file = "memory.low"
+        }
+        self.open_path(file, true).and_then(|mut file| {
+            file.write_all(limit.to_string().as_ref())
+                .map_err(|e| Error::with_cause(WriteFailed, e))
+        })
     }
 
     /// Set how likely the kernel is to swap out parts of the address space used by the control
@@ -662,6 +800,22 @@ impl MemController {
                     .map_err(|e| Error::with_cause(WriteFailed, e))
             })
     }
+
+    pub fn disable_oom_killer(&self) -> Result<()> {
+        self.open_path("memory.oom_control", true)
+            .and_then(|mut file| {
+                file.write_all("1".to_string().as_ref())
+                    .map_err(|e| Error::with_cause(WriteFailed, e))
+            })
+    }
+
+    pub fn register_oom_event(&self, key: &str) -> Result<Receiver<String>> {
+        if self.v2 {
+            events::notify_on_oom_v2(key, self.get_path())
+        } else {
+            events::notify_on_oom_v1(key, self.get_path())
+        }
+    }
 }
 
 impl ControllIdentifier for MemController {
@@ -687,7 +841,21 @@ impl<'a> From<&'a Subsystem> for &'a MemController {
 fn read_u64_from(mut file: File) -> Result<u64> {
     let mut string = String::new();
     match file.read_to_string(&mut string) {
-        Ok(_) => string.trim().parse().map_err(|e| Error::with_cause(ParseError, e)),
+        Ok(_) => string
+            .trim()
+            .parse()
+            .map_err(|e| Error::with_cause(ParseError, e)),
+        Err(e) => Err(Error::with_cause(ReadFailed, e)),
+    }
+}
+
+fn read_i64_from(mut file: File) -> Result<i64> {
+    let mut string = String::new();
+    match file.read_to_string(&mut string) {
+        Ok(_) => string
+            .trim()
+            .parse()
+            .map_err(|e| Error::with_cause(ParseError, e)),
         Err(e) => Err(Error::with_cause(ReadFailed, e)),
     }
 }
@@ -705,6 +873,7 @@ mod tests {
     use crate::memory::{
         parse_memory_stat, parse_numa_stat, parse_oom_control, MemoryStat, NumaStat, OomControl,
     };
+    use std::collections::HashMap;
 
     static GOOD_VALUE: &str = "\
 total=51189 N0=51189 N1=123
@@ -805,6 +974,7 @@ total_unevictable 81920
     #[test]
     fn test_parse_memory_stat() {
         let ok = parse_memory_stat(GOOD_MEMORYSTAT_VAL.to_string()).unwrap();
+        let raw = ok.raw.clone();
         assert_eq!(
             ok,
             MemoryStat {
@@ -844,6 +1014,7 @@ total_unevictable 81920
                 total_inactive_file: 1272135680,
                 total_active_file: 2338816000,
                 total_unevictable: 81920,
+                raw: raw,
             }
         );
     }
diff --git a/src/net_cls.rs b/src/net_cls.rs
index 13a2366..4d923ff 100644
--- a/src/net_cls.rs
+++ b/src/net_cls.rs
@@ -11,12 +11,11 @@ use std::fs::File;
 use std::io::{Read, Write};
 use std::path::PathBuf;
 
-use crate::error::*;
 use crate::error::ErrorKind::*;
+use crate::error::*;
 
 use crate::{
-    ControllIdentifier, ControllerInternal, Controllers, NetworkResources, Resources,
-    Subsystem,
+    ControllIdentifier, ControllerInternal, Controllers, NetworkResources, Resources, Subsystem,
 };
 
 /// A controller that allows controlling the `net_cls` subsystem of a Cgroup.
@@ -81,7 +80,10 @@ impl<'a> From<&'a Subsystem> for &'a NetClsController {
 fn read_u64_from(mut file: File) -> Result<u64> {
     let mut string = String::new();
     match file.read_to_string(&mut string) {
-        Ok(_) => string.trim().parse().map_err(|e| Error::with_cause(ParseError, e)),
+        Ok(_) => string
+            .trim()
+            .parse()
+            .map_err(|e| Error::with_cause(ParseError, e)),
         Err(e) => Err(Error::with_cause(ReadFailed, e)),
     }
 }
@@ -102,7 +104,8 @@ impl NetClsController {
         self.open_path("net_cls.classid", true)
             .and_then(|mut file| {
                 let s = format!("{:#08X}", class);
-                file.write_all(s.as_ref()).map_err(|e| Error::with_cause(WriteFailed, e))
+                file.write_all(s.as_ref())
+                    .map_err(|e| Error::with_cause(WriteFailed, e))
             })
     }
 
diff --git a/src/net_prio.rs b/src/net_prio.rs
index 6d4cbe0..a4d0b6e 100644
--- a/src/net_prio.rs
+++ b/src/net_prio.rs
@@ -12,12 +12,11 @@ use std::fs::File;
 use std::io::{BufRead, BufReader, Read, Write};
 use std::path::PathBuf;
 
-use crate::error::*;
 use crate::error::ErrorKind::*;
+use crate::error::*;
 
 use crate::{
-    ControllIdentifier, ControllerInternal, Controllers, NetworkResources, Resources,
-    Subsystem,
+    ControllIdentifier, ControllerInternal, Controllers, NetworkResources, Resources, Subsystem,
 };
 
 /// A controller that allows controlling the `net_prio` subsystem of a Cgroup.
@@ -82,7 +81,10 @@ impl<'a> From<&'a Subsystem> for &'a NetPrioController {
 fn read_u64_from(mut file: File) -> Result<u64> {
     let mut string = String::new();
     match file.read_to_string(&mut string) {
-        Ok(_) => string.trim().parse().map_err(|e| Error::with_cause(ParseError, e)),
+        Ok(_) => string
+            .trim()
+            .parse()
+            .map_err(|e| Error::with_cause(ParseError, e)),
         Err(e) => Err(Error::with_cause(ReadFailed, e)),
     }
 }
diff --git a/src/pid.rs b/src/pid.rs
index e4c4100..f1ed845 100644
--- a/src/pid.rs
+++ b/src/pid.rs
@@ -1,4 +1,5 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 Ant Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
@@ -11,11 +12,12 @@ use std::fs::File;
 use std::io::{Read, Write};
 use std::path::PathBuf;
 
-use crate::error::*;
 use crate::error::ErrorKind::*;
+use crate::error::*;
 
 use crate::{
-    ControllIdentifier, ControllerInternal, Controllers, PidResources, Resources, Subsystem,
+    parse_max_value, ControllIdentifier, ControllerInternal, Controllers, MaxValue, PidResources,
+    Resources, Subsystem,
 };
 
 /// A controller that allows controlling the `pids` subsystem of a Cgroup.
@@ -23,22 +25,7 @@ use crate::{
 pub struct PidController {
     base: PathBuf,
     path: PathBuf,
-}
-
-/// The values found in the `pids.max` file in a Cgroup's `pids` subsystem.
-#[derive(Eq, PartialEq, Copy, Clone, Debug)]
-pub enum PidMax {
-    /// This value is returned when the text found `pids.max` is `"max"`.
-    Max,
-    /// When the value in `pids.max` is a numerical value, they are returned via this enum field.
-    Value(i64),
-}
-
-impl Default for PidMax {
-    /// By default, (as per the kernel) `pids.max` should contain `"max"`.
-    fn default() -> Self {
-        PidMax::Max
-    }
+    v2: bool,
 }
 
 impl ControllerInternal for PidController {
@@ -55,6 +42,10 @@ impl ControllerInternal for PidController {
         &self.base
     }
 
+    fn is_v2(&self) -> bool {
+        self.v2
+    }
+
     fn apply(&self, res: &Resources) -> Result<()> {
         // get the resources that apply to this controller
         let pidres: &PidResources = &res.pid;
@@ -104,7 +95,10 @@ impl<'a> From<&'a Subsystem> for &'a PidController {
 fn read_u64_from(mut file: File) -> Result<u64> {
     let mut string = String::new();
     match file.read_to_string(&mut string) {
-        Ok(_) => string.trim().parse().map_err(|e| Error::with_cause(ParseError, e)),
+        Ok(_) => string
+            .trim()
+            .parse()
+            .map_err(|e| Error::with_cause(ParseError, e)),
         Err(e) => Err(Error::with_cause(ReadFailed, e)),
     }
 }
@@ -112,12 +106,15 @@ fn read_u64_from(mut file: File) -> Result<u64> {
 impl PidController {
     /// Constructors a new `PidController` instance, with `oroot` serving as the controller's root
     /// directory.
-    pub fn new(oroot: PathBuf) -> Self {
+    pub fn new(oroot: PathBuf, v2: bool) -> Self {
         let mut root = oroot;
-        root.push(Self::controller_type().to_string());
+        if !v2 {
+            root.push(Self::controller_type().to_string());
+        }
         Self {
             base: root.clone(),
             path: root,
+            v2: v2,
         }
     }
 
@@ -145,19 +142,12 @@ impl PidController {
     }
 
     /// The maximum number of processes that can exist at one time in the control group.
-    pub fn get_pid_max(&self) -> Result<PidMax> {
+    pub fn get_pid_max(&self) -> Result<MaxValue> {
         self.open_path("pids.max", false).and_then(|mut file| {
             let mut string = String::new();
             let res = file.read_to_string(&mut string);
             match res {
-                Ok(_) => if string.trim() == "max" {
-                    Ok(PidMax::Max)
-                } else {
-                    match string.trim().parse() {
-                        Ok(val) => Ok(PidMax::Value(val)),
-                        Err(e) => Err(Error::with_cause(ParseError, e)),
-                    }
-                },
+                Ok(_) => parse_max_value(&string),
                 Err(e) => Err(Error::with_cause(ReadFailed, e)),
             }
         })
@@ -168,12 +158,9 @@ impl PidController {
     /// Note that if `get_pid_current()` returns a higher number than what you
     /// are about to set (`max_pid`), then no processess will be killed. Additonally, attaching
     /// extra processes to a control group disregards the limit.
-    pub fn set_pid_max(&self, max_pid: PidMax) -> Result<()> {
+    pub fn set_pid_max(&self, max_pid: MaxValue) -> Result<()> {
         self.open_path("pids.max", true).and_then(|mut file| {
-            let string_to_write = match max_pid {
-                PidMax::Max => "max".to_string(),
-                PidMax::Value(num) => num.to_string(),
-            };
+            let string_to_write = max_pid.to_string();
             match file.write_all(string_to_write.as_ref()) {
                 Ok(_) => Ok(()),
                 Err(e) => Err(Error::with_cause(WriteFailed, e)),
diff --git a/src/rdma.rs b/src/rdma.rs
index 0611bb6..1de7458 100644
--- a/src/rdma.rs
+++ b/src/rdma.rs
@@ -11,8 +11,8 @@ use std::fs::File;
 use std::io::{Read, Write};
 use std::path::PathBuf;
 
-use crate::error::*;
 use crate::error::ErrorKind::*;
+use crate::error::*;
 
 use crate::{ControllIdentifier, ControllerInternal, Controllers, Resources, Subsystem};
 
diff --git a/src/systemd.rs b/src/systemd.rs
new file mode 100644
index 0000000..9c9d36d
--- /dev/null
+++ b/src/systemd.rs
@@ -0,0 +1,76 @@
+// Copyright (c) 2020 Ant Group
+//
+// SPDX-License-Identifier: Apache-2.0 or MIT
+//
+
+//! This module contains the implementation of the `systemd` cgroup subsystem.
+//!
+use std::path::PathBuf;
+
+use crate::error::ErrorKind::*;
+use crate::error::*;
+
+use crate::{ControllIdentifier, ControllerInternal, Controllers, Resources, Subsystem};
+
+/// A controller that allows controlling the `systemd` subsystem of a Cgroup.
+///
+#[derive(Debug, Clone)]
+pub struct SystemdController {
+    base: PathBuf,
+    path: PathBuf,
+    v2: bool,
+}
+
+impl ControllerInternal for SystemdController {
+    fn control_type(&self) -> Controllers {
+        Controllers::Systemd
+    }
+    fn get_path(&self) -> &PathBuf {
+        &self.path
+    }
+    fn get_path_mut(&mut self) -> &mut PathBuf {
+        &mut self.path
+    }
+    fn get_base(&self) -> &PathBuf {
+        &self.base
+    }
+
+    fn apply(&self, _res: &Resources) -> Result<()> {
+        Ok(())
+    }
+}
+
+impl ControllIdentifier for SystemdController {
+    fn controller_type() -> Controllers {
+        Controllers::Systemd
+    }
+}
+
+impl<'a> From<&'a Subsystem> for &'a SystemdController {
+    fn from(sub: &'a Subsystem) -> &'a SystemdController {
+        unsafe {
+            match sub {
+                Subsystem::Systemd(c) => c,
+                _ => {
+                    assert_eq!(1, 0);
+                    ::std::mem::uninitialized()
+                }
+            }
+        }
+    }
+}
+
+impl SystemdController {
+    /// Constructs a new `SystemdController` with `oroot` serving as the root of the control group.
+    pub fn new(oroot: PathBuf, v2: bool) -> Self {
+        let mut root = oroot;
+        if !v2 {
+            root.push(Self::controller_type().to_string());
+        }
+        Self {
+            base: root.clone(),
+            path: root,
+            v2: v2,
+        }
+    }
+}
diff --git a/tests/builder.rs b/tests/builder.rs
index 05e2919..fced12a 100644
--- a/tests/builder.rs
+++ b/tests/builder.rs
@@ -1,26 +1,28 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 And Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
 
 //! Some simple tests covering the builder pattern for control groups.
-use cgroups::*;
-use cgroups::cpu::*;
-use cgroups::devices::*;
-use cgroups::pid::*;
-use cgroups::memory::*;
-use cgroups::net_cls::*;
-use cgroups::hugetlb::*;
 use cgroups::blkio::*;
 use cgroups::cgroup_builder::*;
+use cgroups::cpu::*;
+use cgroups::devices::*;
+use cgroups::hugetlb::*;
+use cgroups::memory::*;
+use cgroups::net_cls::*;
+use cgroups::pid::*;
+use cgroups::*;
 
 #[test]
 pub fn test_cpu_res_build() {
-    let v1 = crate::hierarchies::V1::new();
-    let cg: Cgroup = CgroupBuilder::new("test_cpu_res_build", &v1)
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg: Cgroup = CgroupBuilder::new("test_cpu_res_build", h)
         .cpu()
-            .shares(85)
-            .done()
+        .shares(85)
+        .done()
         .build();
 
     {
@@ -34,19 +36,22 @@ pub fn test_cpu_res_build() {
 
 #[test]
 pub fn test_memory_res_build() {
-    let v1 = crate::hierarchies::V1::new();
-    let cg: Cgroup = CgroupBuilder::new("test_memory_res_build", &v1)
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg: Cgroup = CgroupBuilder::new("test_memory_res_build", h)
         .memory()
-            .kernel_memory_limit(128 * 1024 * 1024)
-            .swappiness(70)
-            .memory_hard_limit(1024 * 1024 * 1024)
-            .done()
+        .kernel_memory_limit(128 * 1024 * 1024)
+        .swappiness(70)
+        .memory_hard_limit(1024 * 1024 * 1024)
+        .done()
         .build();
 
     {
         let c: &MemController = cg.controller_of().unwrap();
-        assert_eq!(c.kmem_stat().limit_in_bytes, 128 * 1024 * 1024);
-        assert_eq!(c.memory_stat().swappiness, 70);
+        if !c.v2() {
+            assert_eq!(c.kmem_stat().limit_in_bytes, 128 * 1024 * 1024);
+            assert_eq!(c.memory_stat().swappiness, 70);
+        }
         assert_eq!(c.memory_stat().limit_in_bytes, 1024 * 1024 * 1024);
     }
 
@@ -55,17 +60,18 @@ pub fn test_memory_res_build() {
 
 #[test]
 pub fn test_pid_res_build() {
-    let v1 = crate::hierarchies::V1::new();
-    let cg: Cgroup = CgroupBuilder::new("test_pid_res_build", &v1)
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg: Cgroup = CgroupBuilder::new("test_pid_res_build", h)
         .pid()
-            .maximum_number_of_processes(PidMax::Value(123))
-            .done()
+        .maximum_number_of_processes(MaxValue::Value(123))
+        .done()
         .build();
 
     {
         let c: &PidController = cg.controller_of().unwrap();
         assert!(c.get_pid_max().is_ok());
-        assert_eq!(c.get_pid_max().unwrap(), PidMax::Value(123));
+        assert_eq!(c.get_pid_max().unwrap(), MaxValue::Value(123));
     }
 
     cg.delete();
@@ -74,37 +80,43 @@ pub fn test_pid_res_build() {
 #[test]
 #[ignore] // ignore this test for now, not sure why my kernel doesn't like it
 pub fn test_devices_res_build() {
-    let v1 = crate::hierarchies::V1::new();
-    let cg: Cgroup = CgroupBuilder::new("test_devices_res_build", &v1)
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg: Cgroup = CgroupBuilder::new("test_devices_res_build", h)
         .devices()
-            .device(1, 6, DeviceType::Char, true,
-                    vec![DevicePermissions::Read])
-            .done()
+        .device(1, 6, DeviceType::Char, true, vec![DevicePermissions::Read])
+        .done()
         .build();
 
     {
         let c: &DevicesController = cg.controller_of().unwrap();
         assert!(c.allowed_devices().is_ok());
-        assert_eq!(c.allowed_devices().unwrap(), vec![
-                   DeviceResource {
-                       allow: true,
-                       devtype: DeviceType::Char,
-                       major: 1,
-                       minor: 6,
-                       access: vec![DevicePermissions::Read],
-                   }
-        ]);
+        assert_eq!(
+            c.allowed_devices().unwrap(),
+            vec![DeviceResource {
+                allow: true,
+                devtype: DeviceType::Char,
+                major: 1,
+                minor: 6,
+                access: vec![DevicePermissions::Read],
+            }]
+        );
     }
     cg.delete();
 }
 
 #[test]
 pub fn test_network_res_build() {
-    let v1 = crate::hierarchies::V1::new();
-    let cg: Cgroup = CgroupBuilder::new("test_network_res_build", &v1)
+    let h = cgroups::hierarchies::auto();
+    if h.v2() {
+        // FIXME add cases for v2
+        return;
+    }
+    let h = Box::new(&*h);
+    let cg: Cgroup = CgroupBuilder::new("test_network_res_build", h)
         .network()
-            .class_id(1337)
-            .done()
+        .class_id(1337)
+        .done()
         .build();
 
     {
@@ -117,28 +129,38 @@ pub fn test_network_res_build() {
 
 #[test]
 pub fn test_hugepages_res_build() {
-    let v1 = crate::hierarchies::V1::new();
-    let cg: Cgroup = CgroupBuilder::new("test_hugepages_res_build", &v1)
+    let h = cgroups::hierarchies::auto();
+    if h.v2() {
+        // FIXME add cases for v2
+        return;
+    }
+    let h = Box::new(&*h);
+    let cg: Cgroup = CgroupBuilder::new("test_hugepages_res_build", h)
         .hugepages()
-            .limit("2MB".to_string(), 4 * 2 * 1024 * 1024)
-            .done()
+        .limit("2MB".to_string(), 4 * 2 * 1024 * 1024)
+        .done()
         .build();
 
     {
         let c: &HugeTlbController = cg.controller_of().unwrap();
         assert!(c.limit_in_bytes(&"2MB".to_string()).is_ok());
-        assert_eq!(c.limit_in_bytes(&"2MB".to_string()).unwrap(), 4 * 2 * 1024 * 1024);
+        assert_eq!(
+            c.limit_in_bytes(&"2MB".to_string()).unwrap(),
+            4 * 2 * 1024 * 1024
+        );
     }
     cg.delete();
 }
 
 #[test]
+#[ignore] // high version kernel not support `blkio.weight`
 pub fn test_blkio_res_build() {
-    let v1 = crate::hierarchies::V1::new();
-    let cg: Cgroup = CgroupBuilder::new("test_blkio_res_build", &v1)
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg: Cgroup = CgroupBuilder::new("test_blkio_res_build", h)
         .blkio()
-            .weight(100)
-            .done()
+        .weight(Some(100))
+        .done()
         .build();
 
     {
diff --git a/tests/cgroup.rs b/tests/cgroup.rs
index 83b5ebe..915a5f9 100644
--- a/tests/cgroup.rs
+++ b/tests/cgroup.rs
@@ -1,19 +1,28 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 And Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
 
 //! Simple unit tests about the control groups system.
-use cgroups::{Cgroup, CgroupPid};
+use cgroups::memory::{MemController, SetMemory};
+use cgroups::Controller;
+use cgroups::{Cgroup, CgroupPid, Hierarchy, Subsystem};
+use std::collections::HashMap;
 
 #[test]
 fn test_tasks_iterator() {
-    let hier = cgroups::hierarchies::V1::new();
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
     let pid = libc::pid_t::from(nix::unistd::getpid()) as u64;
-    let cg = Cgroup::new(&hier, String::from("test_tasks_iterator"));
+    let cg = Cgroup::new(h, String::from("test_tasks_iterator"));
     {
         // Add a task to the control group.
-        cg.add_task(CgroupPid::from(pid));
+        cg.add_task(CgroupPid::from(pid)).unwrap();
+
+        use std::{thread, time};
+        thread::sleep(time::Duration::from_millis(100));
+
         let mut tasks = cg.tasks().into_iter();
         // Verify that the task is indeed in the control group
         assert_eq!(tasks.next(), Some(CgroupPid::from(pid)));
@@ -28,3 +37,81 @@ fn test_tasks_iterator() {
     }
     cg.delete();
 }
+
+#[test]
+fn test_cgroup_with_relative_paths() {
+    if cgroups::hierarchies::is_cgroup2_unified_mode() {
+        return;
+    }
+    let h = cgroups::hierarchies::auto();
+    let cgroup_root = h.root();
+    let h = Box::new(&*h);
+    let mut relative_paths = HashMap::new();
+    let mem_relative_path = "/mmm/abc/def";
+    relative_paths.insert("memory".to_string(), mem_relative_path.to_string());
+    let cgroup_name = "test_cgroup_with_relative_paths";
+
+    let cg = Cgroup::new_with_relative_paths(h, String::from(cgroup_name), relative_paths);
+    {
+        let subsystems = cg.subsystems();
+        subsystems.into_iter().for_each(|sub| match sub {
+            Subsystem::Pid(c) => {
+                let cgroup_path = c.path().to_str().unwrap();
+                let relative_path = "/pids/";
+                // cgroup_path = cgroup_root + relative_path + cgroup_name
+                assert_eq!(
+                    cgroup_path,
+                    format!(
+                        "{}{}{}",
+                        cgroup_root.to_str().unwrap(),
+                        relative_path,
+                        cgroup_name
+                    )
+                );
+            }
+            Subsystem::Mem(c) => {
+                let cgroup_path = c.path().to_str().unwrap();
+                // cgroup_path = cgroup_root + relative_path + cgroup_name
+                assert_eq!(
+                    cgroup_path,
+                    format!(
+                        "{}/memory{}/{}",
+                        cgroup_root.to_str().unwrap(),
+                        mem_relative_path,
+                        cgroup_name
+                    )
+                );
+            }
+            _ => {}
+        });
+    }
+    cg.delete();
+}
+
+#[test]
+fn test_cgroup_v2() {
+    if !cgroups::hierarchies::is_cgroup2_unified_mode() {
+        return;
+    }
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg = Cgroup::new_with_relative_paths(h, String::from("test_v2"), HashMap::new());
+
+    let mem_controller: &MemController = cg.controller_of().unwrap();
+    let (mem, swp, rev) = (4 * 1024 * 1000, 2 * 1024 * 1000, 1024 * 1000);
+
+    let _ = mem_controller.set_limit(mem);
+    let _ = mem_controller.set_memswap_limit(swp);
+    let _ = mem_controller.set_soft_limit(rev);
+
+    let memory_stat = mem_controller.memory_stat();
+    println!("memory_stat {:?}", memory_stat);
+    assert_eq!(mem, memory_stat.limit_in_bytes);
+    assert_eq!(rev, memory_stat.soft_limit_in_bytes);
+
+    let memswap = mem_controller.memswap();
+    println!("memswap {:?}", memswap);
+    assert_eq!(swp, memswap.limit_in_bytes);
+
+    cg.delete();
+}
diff --git a/tests/cpuset.rs b/tests/cpuset.rs
index 2f5ff93..3563354 100644
--- a/tests/cpuset.rs
+++ b/tests/cpuset.rs
@@ -1,16 +1,20 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 And Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
 
 use cgroups::cpuset::CpuSetController;
 use cgroups::error::ErrorKind;
-use cgroups::Cgroup;
+use cgroups::{Cgroup, CgroupPid, CpuResources, Hierarchy, Resources};
+
+use std::fs;
 
 #[test]
 fn test_cpuset_memory_pressure_root_cg() {
-    let hier = cgroups::hierarchies::V1::new();
-    let cg = Cgroup::new(&hier, String::from("test_cpuset_memory_pressure_root_cg"));
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg = Cgroup::new(h, String::from("test_cpuset_memory_pressure_root_cg"));
     {
         let cpuset: &CpuSetController = cg.controller_of().unwrap();
 
@@ -20,3 +24,73 @@ fn test_cpuset_memory_pressure_root_cg() {
     }
     cg.delete();
 }
+
+#[test]
+fn test_cpuset_set_cpus() {
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg = Cgroup::new(h, String::from("test_cpuset_set_cpus"));
+    {
+        let cpuset: &CpuSetController = cg.controller_of().unwrap();
+
+        let set = cpuset.cpuset();
+        if cg.v2() {
+            assert_eq!(0, set.cpus.len());
+        } else {
+            // for cgroup v1, cpuset is copied from parent.
+            assert_eq!(true, set.cpus.len() > 0);
+        }
+
+        // 0
+        let r = cpuset.set_cpus("0");
+        assert_eq!(true, r.is_ok());
+
+        let set = cpuset.cpuset();
+        assert_eq!(1, set.cpus.len());
+        assert_eq!((0, 0), set.cpus[0]);
+
+        // all cpus in system
+        let cpus =
+            fs::read_to_string("/sys/fs/cgroup/cpuset.cpus.effective").unwrap_or("".to_string());
+        let cpus = cpus.trim();
+        if cpus != "" {
+            let r = cpuset.set_cpus(&cpus);
+            assert_eq!(true, r.is_ok());
+            let set = cpuset.cpuset();
+            assert_eq!(1, set.cpus.len());
+            assert_eq!(format!("{}-{}", set.cpus[0].0, set.cpus[0].1), cpus);
+        }
+    }
+    cg.delete();
+}
+
+#[test]
+fn test_cpuset_set_cpus_add_task() {
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg = Cgroup::new(h, String::from("test_cpuset_set_cpus_add_task/sub-dir"));
+
+    let cpuset: &CpuSetController = cg.controller_of().unwrap();
+    let set = cpuset.cpuset();
+    if cg.v2() {
+        assert_eq!(0, set.cpus.len());
+    } else {
+        // for cgroup v1, cpuset is copied from parent.
+        assert_eq!(true, set.cpus.len() > 0);
+    }
+
+    // Add a task to the control group.
+    let pid_i = libc::pid_t::from(nix::unistd::getpid()) as u64;
+    let _ = cg.add_task(CgroupPid::from(pid_i));
+    let tasks = cg.tasks();
+    assert_eq!(true, tasks.len() > 0);
+    println!("tasks after added: {:?}", tasks);
+
+    // remove task
+    let _ = cg.remove_task(CgroupPid::from(pid_i));
+    let tasks = cg.tasks();
+    println!("tasks after deleted: {:?}", tasks);
+    assert_eq!(0, tasks.len());
+
+    cg.delete();
+}
diff --git a/tests/devices.rs b/tests/devices.rs
index b79c626..adb7e13 100644
--- a/tests/devices.rs
+++ b/tests/devices.rs
@@ -1,4 +1,5 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 And Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
@@ -6,12 +7,18 @@
 //! Integration tests about the devices subsystem
 
 use cgroups::devices::{DevicePermissions, DeviceType, DevicesController};
-use cgroups::{Cgroup, DeviceResource};
+use cgroups::{Cgroup, DeviceResource, Hierarchy};
 
 #[test]
 fn test_devices_parsing() {
-    let hier = cgroups::hierarchies::V1::new();
-    let cg = Cgroup::new(&hier, String::from("test_devices_parsing"));
+    // now only v2
+    if cgroups::hierarchies::is_cgroup2_unified_mode() {
+        return;
+    }
+
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg = Cgroup::new(h, String::from("test_devices_parsing"));
     {
         let devices: &DevicesController = cg.controller_of().unwrap();
 
diff --git a/tests/hugetlb.rs b/tests/hugetlb.rs
new file mode 100644
index 0000000..095243e
--- /dev/null
+++ b/tests/hugetlb.rs
@@ -0,0 +1,48 @@
+// Copyright (c) 2020 And Group
+//
+// SPDX-License-Identifier: Apache-2.0 or MIT
+//
+
+//! Integration tests about the hugetlb subsystem
+use cgroups::hugetlb::{self, HugeTlbController};
+use cgroups::Controller;
+use cgroups::{Cgroup, Hierarchy};
+
+use cgroups::error::ErrorKind::*;
+use cgroups::error::*;
+use std::fs;
+
+#[test]
+fn test_hugetlb_sizes() {
+    // now only v2
+    if cgroups::hierarchies::is_cgroup2_unified_mode() {
+        return;
+    }
+
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg = Cgroup::new(h, String::from("test_hugetlb_sizes"));
+    {
+        let hugetlb_controller: &HugeTlbController = cg.controller_of().unwrap();
+        let sizes = hugetlb_controller.get_sizes();
+
+        // test sizes count
+        let sizes = hugetlb_controller.get_sizes();
+        let sizes_count = fs::read_dir(hugetlb::HUGEPAGESIZE_DIR).unwrap().count();
+        assert_eq!(sizes.len(), sizes_count);
+
+        for size in sizes {
+            let supported = hugetlb_controller.size_supported(&size);
+            assert_eq!(supported, true);
+            assert_no_error(hugetlb_controller.failcnt(&size));
+            assert_no_error(hugetlb_controller.limit_in_bytes(&size));
+            assert_no_error(hugetlb_controller.usage_in_bytes(&size));
+            assert_no_error(hugetlb_controller.max_usage_in_bytes(&size));
+        }
+    }
+    cg.delete();
+}
+
+fn assert_no_error(r: Result<u64>) {
+    assert_eq!(!r.is_err(), true)
+}
diff --git a/tests/memory.rs b/tests/memory.rs
new file mode 100644
index 0000000..2d64906
--- /dev/null
+++ b/tests/memory.rs
@@ -0,0 +1,93 @@
+// Copyright (c) 2020 And Group
+//
+// SPDX-License-Identifier: Apache-2.0 or MIT
+//
+
+//! Integration tests about the hugetlb subsystem
+use cgroups::memory::{MemController, SetMemory};
+use cgroups::Controller;
+use cgroups::{Cgroup, MaxValue};
+
+#[test]
+fn test_disable_oom_killer() {
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg = Cgroup::new(h, String::from("test_disable_oom_killer"));
+    {
+        let mem_controller: &MemController = cg.controller_of().unwrap();
+
+        // before disable
+        let m = mem_controller.memory_stat();
+        assert_eq!(m.oom_control.oom_kill_disable, false);
+
+        // now only v1
+        if !mem_controller.v2() {
+            // disable oom killer
+            let r = mem_controller.disable_oom_killer();
+            assert_eq!(r.is_err(), false);
+
+            // after disable
+            let m = mem_controller.memory_stat();
+            assert_eq!(m.oom_control.oom_kill_disable, true);
+        }
+    }
+    cg.delete();
+}
+
+#[test]
+fn set_mem_v2() {
+    let h = cgroups::hierarchies::auto();
+    if !h.v2() {
+        return;
+    }
+
+    let h = Box::new(&*h);
+    let cg = Cgroup::new(h, String::from("set_mem_v2"));
+    {
+        let mem_controller: &MemController = cg.controller_of().unwrap();
+
+        // before disable
+        let m = mem_controller.get_mem().unwrap();
+        // case 1: get default value
+        assert_eq!(m.low, Some(MaxValue::Value(0)));
+        assert_eq!(m.min, Some(MaxValue::Value(0)));
+        assert_eq!(m.high, Some(MaxValue::Max));
+        assert_eq!(m.max, Some(MaxValue::Max));
+
+        // case 2: set parts
+        let m = SetMemory {
+            low: Some(MaxValue::Value(1024 * 1024 * 2)),
+            high: Some(MaxValue::Value(1024 * 1024 * 1024 * 2)),
+            min: Some(MaxValue::Value(1024 * 1024 * 3)),
+            max: None,
+        };
+        let r = mem_controller.set_mem(m);
+        assert_eq!(true, r.is_ok());
+
+        let m = mem_controller.get_mem().unwrap();
+        // get
+        assert_eq!(m.low, Some(MaxValue::Value(1024 * 1024 * 2)));
+        assert_eq!(m.min, Some(MaxValue::Value(1024 * 1024 * 3)));
+        assert_eq!(m.high, Some(MaxValue::Value(1024 * 1024 * 1024 * 2)));
+        assert_eq!(m.max, Some(MaxValue::Max));
+
+        // case 3: set parts
+        let m = SetMemory {
+            max: Some(MaxValue::Value(1024 * 1024 * 1024 * 2)),
+            min: Some(MaxValue::Value(1024 * 1024 * 4)),
+            high: Some(MaxValue::Max),
+            low: None,
+        };
+        let r = mem_controller.set_mem(m);
+        assert_eq!(true, r.is_ok());
+
+        let m = mem_controller.get_mem().unwrap();
+        // get
+        assert_eq!(m.low, Some(MaxValue::Value(1024 * 1024 * 2)));
+        assert_eq!(m.min, Some(MaxValue::Value(1024 * 1024 * 4)));
+        assert_eq!(m.max, Some(MaxValue::Value(1024 * 1024 * 1024 * 2)));
+        assert_eq!(m.high, Some(MaxValue::Max));
+    }
+
+    cg.delete();
+}
diff --git a/tests/pids.rs b/tests/pids.rs
index 0cc0a95..0449a0d 100644
--- a/tests/pids.rs
+++ b/tests/pids.rs
@@ -1,12 +1,13 @@
 // Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 And Group
 //
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
 
 //! Integration tests about the pids subsystem
-use cgroups::pid::{PidController, PidMax};
+use cgroups::pid::PidController;
 use cgroups::Controller;
-use cgroups::{Cgroup, CgroupPid, PidResources, Resources};
+use cgroups::{Cgroup, CgroupPid, Hierarchy, MaxValue, PidResources, Resources};
 
 use nix::sys::wait::{waitpid, WaitStatus};
 use nix::unistd::{fork, ForkResult, Pid};
@@ -17,22 +18,24 @@ use std::thread;
 
 #[test]
 fn create_and_delete_cgroup() {
-    let hier = cgroups::hierarchies::V1::new();
-    let cg = Cgroup::new(&hier, String::from("create_and_delete_cgroup"));
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg = Cgroup::new(h, String::from("create_and_delete_cgroup"));
     {
         let pidcontroller: &PidController = cg.controller_of().unwrap();
-        pidcontroller.set_pid_max(PidMax::Value(1337));
+        pidcontroller.set_pid_max(MaxValue::Value(1337));
         let max = pidcontroller.get_pid_max();
         assert!(max.is_ok());
-        assert_eq!(max.unwrap(), PidMax::Value(1337));
+        assert_eq!(max.unwrap(), MaxValue::Value(1337));
     }
     cg.delete();
 }
 
 #[test]
 fn test_pids_current_is_zero() {
-    let hier = cgroups::hierarchies::V1::new();
-    let cg = Cgroup::new(&hier, String::from("test_pids_current_is_zero"));
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg = Cgroup::new(h, String::from("test_pids_current_is_zero"));
     {
         let pidcontroller: &PidController = cg.controller_of().unwrap();
         let current = pidcontroller.get_pid_current();
@@ -43,8 +46,9 @@ fn test_pids_current_is_zero() {
 
 #[test]
 fn test_pids_events_is_zero() {
-    let hier = cgroups::hierarchies::V1::new();
-    let cg = Cgroup::new(&hier, String::from("test_pids_events_is_zero"));
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg = Cgroup::new(h, String::from("test_pids_events_is_zero"));
     {
         let pidcontroller: &PidController = cg.controller_of().unwrap();
         let events = pidcontroller.get_pid_events();
@@ -56,8 +60,9 @@ fn test_pids_events_is_zero() {
 
 #[test]
 fn test_pid_events_is_not_zero() {
-    let hier = cgroups::hierarchies::V1::new();
-    let cg = Cgroup::new(&hier, String::from("test_pid_events_is_not_zero"));
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg = Cgroup::new(h, String::from("test_pid_events_is_not_zero"));
     {
         let pids: &PidController = cg.controller_of().unwrap();
         let before = pids.get_pid_events();
@@ -66,13 +71,13 @@ fn test_pid_events_is_not_zero() {
         match fork() {
             Ok(ForkResult::Parent { child, .. }) => {
                 // move the process into the control group
-                pids.add_task(&(pid_t::from(child) as u64).into());
+                let _ = pids.add_task(&(pid_t::from(child) as u64).into());
 
                 println!("added task to cg: {:?}", child);
 
                 // Set limit to one
-                pids.set_pid_max(PidMax::Value(1));
-                println!("err = {:?}", pids.get_pid_max());
+                let _ = pids.set_pid_max(MaxValue::Value(1));
+                println!("current pid.max = {:?}", pids.get_pid_max());
 
                 // wait on the child
                 let res = waitpid(child, None);
@@ -89,7 +94,7 @@ fn test_pid_events_is_not_zero() {
             }
             Ok(ForkResult::Child) => loop {
                 let pids_max = pids.get_pid_max();
-                if pids_max.is_ok() && pids_max.unwrap() == PidMax::Value(1) {
+                if pids_max.is_ok() && pids_max.unwrap() == MaxValue::Value(1) {
                     if let Err(_) = fork() {
                         unsafe { libc::exit(0) };
                     } else {
diff --git a/tests/resources.rs b/tests/resources.rs
index c612df1..665e4d0 100644
--- a/tests/resources.rs
+++ b/tests/resources.rs
@@ -1,16 +1,23 @@
+// Copyright (c) 2018 Levente Kurusa
+// Copyright (c) 2020 And Group
+//
+// SPDX-License-Identifier: Apache-2.0 or MIT
+//
+
 //! Integration test about setting resources using `apply()`
-use cgroups::pid::{PidController, PidMax};
-use cgroups::{Cgroup, PidResources, Resources};
+use cgroups::pid::PidController;
+use cgroups::{Cgroup, Hierarchy, MaxValue, PidResources, Resources};
 
 #[test]
 fn pid_resources() {
-    let hier = cgroups::hierarchies::V1::new();
-    let cg = Cgroup::new(&hier, String::from("pid_resources"));
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg = Cgroup::new(h, String::from("pid_resources"));
     {
         let res = Resources {
             pid: PidResources {
                 update_values: true,
-                maximum_number_of_processes: PidMax::Value(512),
+                maximum_number_of_processes: MaxValue::Value(512),
             },
             ..Default::default()
         };
@@ -20,7 +27,7 @@ fn pid_resources() {
         let pidcontroller: &PidController = cg.controller_of().unwrap();
         let pid_max = pidcontroller.get_pid_max();
         assert_eq!(pid_max.is_ok(), true);
-        assert_eq!(pid_max.unwrap(), PidMax::Value(512));
+        assert_eq!(pid_max.unwrap(), MaxValue::Value(512));
     }
     cg.delete();
 }