Add support for blkio read/write bps device

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

blkiodev/blkiodev.go

@@ -13,3 +13,13 @@ type WeightDevice struct {
 func (w *WeightDevice) String() string {
 	return fmt.Sprintf("%s:%d", w.Path, w.Weight)
 }
+
+// ThrottleDevice is a structure that hold device:rate_per_second pair
+type ThrottleDevice struct {
+	Path string
+	Rate uint64
+}
+
+func (t *ThrottleDevice) String() string {
+	return fmt.Sprintf("%s:%d", t.Path, t.Rate)
+}

sysinfo/sysinfo.go

@@ -63,6 +63,12 @@ type cgroupBlkioInfo struct {
 
 	// Whether Block IO weight_device is supported or not
 	BlkioWeightDevice bool
+
+	// Whether Block IO read limit in bytes per second is supported or not
+	BlkioReadBpsDevice bool
+
+	// Whether Block IO write limit in bytes per second is supported or not
+	BlkioWriteBpsDevice bool
 }
 
 type cgroupCpusetInfo struct {

sysinfo/sysinfo_linux.go

@@ -126,9 +126,21 @@ func checkCgroupBlkioInfo(quiet bool) cgroupBlkioInfo {
 	if !quiet && !weightDevice {
 		logrus.Warn("Your kernel does not support cgroup blkio weight_device")
 	}
+
+	readBpsDevice := cgroupEnabled(mountPoint, "blkio.throttle.read_bps_device")
+	if !quiet && !readBpsDevice {
+		logrus.Warn("Your kernel does not support cgroup blkio throttle.read_bps_device")
+	}
+
+	writeBpsDevice := cgroupEnabled(mountPoint, "blkio.throttle.write_bps_device")
+	if !quiet && !writeBpsDevice {
+		logrus.Warn("Your kernel does not support cgroup blkio throttle.write_bps_device")
+	}
 	return cgroupBlkioInfo{
-		BlkioWeight:       weight,
-		BlkioWeightDevice: weightDevice,
+		BlkioWeight:         weight,
+		BlkioWeightDevice:   weightDevice,
+		BlkioReadBpsDevice:  readBpsDevice,
+		BlkioWriteBpsDevice: writeBpsDevice,
 	}
 }