add support for blkio.weight

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>

cgroups/cgroups.go

@@ -51,6 +51,7 @@ type Cgroup struct {
 	CpuPeriod         int64             `json:"cpu_period,omitempty"`         // CPU period to be used for hardcapping (in usecs). 0 to use system default.
 	CpusetCpus        string            `json:"cpuset_cpus,omitempty"`        // CPU to use
 	CpusetMems        string            `json:"cpuset_mems,omitempty"`        // MEM to use
+	BlkioWeight       int64             `json:"blkio_weight,omitempty"`       // Specifies per cgroup weight, range is from 10 to 1000.
 	Freezer           FreezerState      `json:"freezer,omitempty"`            // set the freeze value for the process
 	Slice             string            `json:"slice,omitempty"`              // Parent slice to use for systemd
 }

cgroups/fs/blkio.go

@@ -15,11 +15,17 @@ type BlkioGroup struct {
 }
 
 func (s *BlkioGroup) Set(d *data) error {
-	// we just want to join this group even though we don't set anything
-	if _, err := d.join("blkio"); err != nil && !cgroups.IsNotFound(err) {
+	dir, err := d.join("blkio")
+	if err != nil && !cgroups.IsNotFound(err) {
 		return err
 	}
 
+	if d.c.BlkioWeight != 0 {
+		if err := writeFile(dir, "blkio.weight", strconv.FormatInt(d.c.BlkioWeight, 10)); err != nil {
+			return err
+		}
+	}
+
 	return nil
 }
 

cgroups/systemd/apply_systemd.go

@@ -119,6 +119,11 @@ func Apply(c *cgroups.Cgroup, pid int) (map[string]string, error) {
 			newProp("CPUShares", uint64(c.CpuShares)))
 	}
 
+	if c.BlkioWeight != 0 {
+		properties = append(properties,
+			newProp("BlockIOWeight", uint64(c.BlkioWeight)))
+	}
+
 	if _, err := theConn.StartTransientUnit(unitName, "replace", properties...); err != nil {
 		return nil, err
 	}