add basic v2 cpu/memory functions

Signed-off-by: bin liu <bin@hyper.sh>

src/cpu.rs

@@ -149,7 +149,12 @@ 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))
         })
@@ -194,4 +199,44 @@ 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))
+            })
+    }
 }