add cgroup subsystem hugetlb

Signed-off-by: Ma Shimiao <mashimiao.fnst@cn.fujitsu.com>

cgroups/fs/apply_raw.go

@@ -19,6 +19,7 @@ var (
 		"cpuset":     &CpusetGroup{},
 		"cpuacct":    &CpuacctGroup{},
 		"blkio":      &BlkioGroup{},
+		"hugetlb":    &HugetlbGroup{},
 		"perf_event": &PerfEventGroup{},
 		"freezer":    &FreezerGroup{},
 	}

cgroups/fs/hugetlb.go

@@ -0,0 +1,29 @@
+package fs
+
+import (
+	"github.com/docker/libcontainer/cgroups"
+	"github.com/docker/libcontainer/configs"
+)
+
+type HugetlbGroup struct {
+}
+
+func (s *HugetlbGroup) Apply(d *data) error {
+	// we just want to join this group even though we don't set anything
+	if _, err := d.join("hugetlb"); err != nil && !cgroups.IsNotFound(err) {
+		return err
+	}
+	return nil
+}
+
+func (s *HugetlbGroup) Set(path string, cgroup *configs.Cgroup) error {
+	return nil
+}
+
+func (s *HugetlbGroup) Remove(d *data) error {
+	return removePath(d.path("hugetlb"))
+}
+
+func (s *HugetlbGroup) GetStats(path string, stats *cgroups.Stats) error {
+	return nil
+}

cgroups/systemd/apply_systemd.go

@@ -38,6 +38,7 @@ var subsystems = map[string]subsystem{
 	"cpuset":     &fs.CpusetGroup{},
 	"cpuacct":    &fs.CpuacctGroup{},
 	"blkio":      &fs.BlkioGroup{},
+	"hugetlb":    &fs.HugetlbGroup{},
 	"perf_event": &fs.PerfEventGroup{},
 	"freezer":    &fs.FreezerGroup{},
 }