Merge pull request #4 from crosbymichael/cgroup-enter

Cleanup systemd cgroup code

Author: vishh

cgroups/fs/cpuset.go

@@ -20,19 +20,10 @@ func (s *CpusetGroup) Set(d *data) error {
 		if err != nil {
 			return err
 		}
-		if err := s.ensureParent(dir); err != nil {
-			return err
-		}
 
-		// because we are not using d.join we need to place the pid into the procs file
-		// unlike the other subsystems
-		if err := writeFile(dir, "cgroup.procs", strconv.Itoa(d.pid)); err != nil {
-			return err
-		}
-		if err := writeFile(dir, "cpuset.cpus", d.c.CpusetCpus); err != nil {
-			return err
-		}
+		return s.SetDir(dir, d.c.CpusetCpus, d.pid)
 	}
+
 	return nil
 }
 
@@ -44,6 +35,24 @@ func (s *CpusetGroup) GetStats(path string, stats *cgroups.Stats) error {
 	return nil
 }
 
+func (s *CpusetGroup) SetDir(dir, value string, pid int) error {
+	if err := s.ensureParent(dir); err != nil {
+		return err
+	}
+
+	// because we are not using d.join we need to place the pid into the procs file
+	// unlike the other subsystems
+	if err := writeFile(dir, "cgroup.procs", strconv.Itoa(pid)); err != nil {
+		return err
+	}
+
+	if err := writeFile(dir, "cpuset.cpus", value); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 func (s *CpusetGroup) getSubsystemSettings(parent string) (cpus []byte, mems []byte, err error) {
 	if cpus, err = ioutil.ReadFile(filepath.Join(parent, "cpuset.cpus")); err != nil {
 		return