config-linux.md: part fix of blkio spec

weightDevice is not direct for bindwidth rate limit, actually
used for weight division.
bpsdeivce limits are different from IOpsdevice, they are limit
rate in bytes, say used for bandwidth limit will be better.

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

config-linux.md

@@ -337,16 +337,25 @@ The following parameters can be specified to set up the controller:
 
 * **`weight`** *(uint16, OPTIONAL)* - specifies per-cgroup weight. This is default weight of the group on all devices until and unless overridden by per-device rules.
 * **`leafWeight`** *(uint16, OPTIONAL)* - equivalents of `weight` for the purpose of deciding how much weight tasks in the given cgroup has while competing with the cgroup's child cgroups.
-* **`weightDevice`** *(array of objects, OPTIONAL)* - specifies the list of devices which will be bandwidth rate limited. The following parameters can be specified per-device:
-    * **`major, minor`** *(int64, REQUIRED)* - major, minor numbers for device. More info in [mknod(1)][mknod.1] man page.
-    * **`weight`** *(uint16, OPTIONAL)* - bandwidth rate for the device.
-    * **`leafWeight`** *(uint16, OPTIONAL)* - bandwidth rate for the device while competing with the cgroup's child cgroups, CFQ scheduler only
+* **`weightDevice`** *(array of objects, OPTIONAL)* - an array of per-device bandwidth weights.
+    Each entry has the following structure:
+    * **`major, minor`** *(int64, REQUIRED)* - major, minor numbers for device.
+        For more information, see the [mknod(1)][mknod.1] man page.
+    * **`weight`** *(uint16, OPTIONAL)* - bandwidth weight for the device.
+    * **`leafWeight`** *(uint16, OPTIONAL)* - bandwidth weight for the device while competing with the cgroup's child cgroups, CFQ scheduler only
 
     You MUST specify at least one of `weight` or `leafWeight` in a given entry, and MAY specify both.
 
-* **`throttleReadBpsDevice`**, **`throttleWriteBpsDevice`**, **`throttleReadIOPSDevice`**, **`throttleWriteIOPSDevice`** *(array of objects, OPTIONAL)* - specify the list of devices which will be IO rate limited.
-    The following parameters can be specified per-device:
-    * **`major, minor`** *(int64, REQUIRED)* - major, minor numbers for device. More info in [mknod(1)][mknod.1] man page.
+* **`throttleReadBpsDevice`**, **`throttleWriteBpsDevice`** *(array of objects, OPTIONAL)* - an array of per-device bandwidth rate limits.
+    Each entry has the following structure:
+    * **`major, minor`** *(int64, REQUIRED)* - major, minor numbers for device.
+        For more information, see the [mknod(1)][mknod.1] man page.
+    * **`rate`** *(uint64, REQUIRED)* - bandwidth rate limit in bytes per second for the device
+
+* **`throttleReadIOPSDevice`**, **`throttleWriteIOPSDevice`** *(array of objects, OPTIONAL)* - an array of per-device IO rate limits.
+    Each entry has the following structure:
+    * **`major, minor`** *(int64, REQUIRED)* - major, minor numbers for device.
+        For more information, see the [mknod(1)][mknod.1] man page.
     * **`rate`** *(uint64, REQUIRED)* - IO rate limit for the device
 
 #### Example