config-linux: add Intel RDT CLOS name sharing support

config-linux.md

@@ -488,17 +488,20 @@ You MUST specify at least one of the `hcaHandles` or `hcaObjects` in a given ent
 ## <a name="configLinuxIntelRdt" />IntelRdt
 
 **`intelRdt`** (object, OPTIONAL) represents the [Intel Resource Director Technology][intel-rdt-cat-kernel-interface].
-    If `intelRdt` is set, the runtime MUST write the container process ID to the `<container-id>/tasks` file in a mounted `resctrl` pseudo-filesystem, using the container ID from [`start`](runtime.md#start) and creating the `<container-id>` directory if necessary.
+    If `intelRdt` is set, the runtime MUST write the container process ID to the `tasks` file in a proper sub-directory in a mounted `resctrl` pseudo-filesystem. That sub-directory name is specified by `closID` parameter.
     If no mounted `resctrl` pseudo-filesystem is available in the [runtime mount namespace](glossary.md#runtime-namespace), the runtime MUST [generate an error](runtime.md#errors).
 
     If `intelRdt` is not set, the runtime MUST NOT manipulate any `resctrl` pseudo-filesystems.
 
 The following parameters can be specified for the container:
 
+* **`closID`** *(string, OPTIONAL)* - specifies the identity for RDT Class of Service (CLOS).
+    If `closID` is set, runtimes MUST create `closID` directory in a mounted `resctrl` pseudo-filesystem if it doesn't exist. If not set, runtimes MUST use the container ID from [`start`](runtime.md#start) and create the `<container-id>` directory.
+
 * **`l3CacheSchema`** *(string, OPTIONAL)* - specifies the schema for L3 cache id and capacity bitmask (CBM).
-    If `l3CacheSchema` is set, runtimes MUST write the value to the `schemata` file in the `<container-id>` directory discussed in `intelRdt`.
+    If `l3CacheSchema` is set, runtimes MUST write the value to the `schemata` file in that sub-directory discussed in `closID`. If not set, runtimes MUST NOT write to `schemata` files in any `resctrl` pseudo-filesystems.
 
-    If `l3CacheSchema` is not set, runtimes MUST NOT write to `schemata` files in any `resctrl` pseudo-filesystems.
+    If `closID` and `l3CacheSchema` both are set, runtimes MUST compare `l3CacheSchema` value with `schemata` file, and [generate an error](runtime.md#errors) if doesn't match.
 
 ### Example
 
@@ -508,6 +511,7 @@ Tasks inside the container only have access to the "upper" 80% of L3 cache id 0
 ```json
 "linux": {
     "intelRdt": {
+        "closID": "guaranteed_group",
         "l3CacheSchema": "L3:0=ffff0;1=3ff"
     }
 }

schema/config-linux.json

@@ -228,6 +228,9 @@
             "intelRdt": {
                 "type": "object",
                 "properties": {
+                    "closID": {
+                        "type": "string"
+                    },
                     "l3CacheSchema": {
                         "type": "string"
                     }

specs-go/config.go

@@ -624,6 +624,8 @@ type LinuxSyscall struct {
 // LinuxIntelRdt has container runtime resource constraints
 // for Intel RDT/CAT which introduced in Linux 4.10 kernel
 type LinuxIntelRdt struct {
+	// The identity for RDT Class of Service
+	ClosID string `json:"closID,omitempty"`
 	// The schema for L3 cache id and capacity bitmask (CBM)
 	// Format: "L3:<cache_id0>=<cbm0>;<cache_id1>=<cbm1>;..."
 	L3CacheSchema string `json:"l3CacheSchema,omitempty"`