config-linux: define default clos for linux.intelRdt

Specify "." as an explicit value for linux.intelRdt.closID to assign a
container to the default CLOS, corresponding to the root of the resctrl
filesystem.

This addition is important after the recently introduced
intelRdt.enableMonitoring field. There is no way to express "enable
monitoring but keep the container in the default CLOS". Users would
otherwise have to rely on pre-created CLOSes or may quickly exhaust
available CLOS entries - in some configurations the number of available
CLOSes (on top of the default) may be as low as three.

Signed-off-by: Markus Lehtonen <[email protected]>

Author: marquiz

config-linux.md

@@ -742,6 +742,8 @@ If `intelRdt` is not set, the runtime MUST NOT manipulate any `resctrl` pseudo-f
 The following parameters can be specified for the container:
 
 * **`closID`** *(string, OPTIONAL)* - specifies the identity for RDT Class of Service (CLOS).
+  As a special case, value `.` means that the container should be assigned to the default CLOS (the
+  root of the resctrl filesystem).
 
 * **`l3CacheSchema`** *(string, OPTIONAL)* - specifies the schema for L3 cache id and capacity bitmask (CBM).
     The value SHOULD start with `L3:` and SHOULD NOT contain newlines.