Add elaboration to quota and burst of CPU resource

Signed-off-by: Kailun Qin <kailun.qin@intel.com>

config-linux.md

@@ -301,7 +301,11 @@ The following parameters can be specified to set up the controller:
 
 * **`shares`** *(uint64, OPTIONAL)* - specifies a relative share of CPU time available to the tasks in a cgroup
 * **`quota`** *(int64, OPTIONAL)* - specifies the replenished amount of time in microseconds for which all tasks in a cgroup can run during one period (as defined by **`period`** below)
+    A value of `-1` indicates that the cgroup does not have any bandwidth restriction in place (i.e., an unconstrained bandwidth group).
+    Any (valid) positive value(s) no smaller than `burst` will enact the specified bandwidth limit.
 * **`burst`** *(uint64, OPTIONAL)* - specifies the maximum amount of accumulated time in microseconds for which all tasks in a cgroup can run additionally for burst during one period (as defined by **`period`** below)
+    A value of `0` for indicates that the cgroup can not accumulate any unused bandwidth. It makes the traditional bandwidth control behavior unchanged.
+    Any (valid) positive value(s) no larger than `quota` will enact the cap on unused bandwidth accumulation.
 * **`period`** *(uint64, OPTIONAL)* - specifies a period of time in microseconds for how regularly a cgroup's access to CPU resources should be reallocated (CFS scheduler only)
 * **`realtimeRuntime`** *(int64, OPTIONAL)* - specifies a period of time in microseconds for the longest continuous period in which the tasks in a cgroup have access to CPU resources
 * **`realtimePeriod`** *(uint64, OPTIONAL)* - same as **`period`** but applies to realtime scheduler only