libcontainer/intelrdt: support ClosID parameter

Handle ClosID parameter of IntelRdt. Makes it possible to use
pre-configured classes/ClosIDs and avoid running out of available IDs
which easily happens with per-container classes.

Remove validator checks for empty L3CacheSchema and MemBwSchema fields
in order to be able to leave them empty, and only specify ClosID for
a pre-configured class.

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

Author: marquiz

libcontainer/configs/intelrdt.go

@@ -1,6 +1,9 @@
 package configs
 
 type IntelRdt 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:"l3_cache_schema,omitempty"`

libcontainer/configs/validate/validator.go

@@ -205,19 +205,16 @@ func (v *ConfigValidator) intelrdt(config *configs.Config) error {
 			return errors.New("intelRdt is specified in config, but Intel RDT is not supported or enabled")
 		}
 
+		if config.IntelRdt.ClosID == "." || config.IntelRdt.ClosID == ".." || strings.Contains(config.IntelRdt.ClosID, "/") {
+			return fmt.Errorf("invalid intelRdt.ClosID %q", config.IntelRdt.ClosID)
+		}
+
 		if !intelrdt.IsCATEnabled() && config.IntelRdt.L3CacheSchema != "" {
 			return errors.New("intelRdt.l3CacheSchema is specified in config, but Intel RDT/CAT is not enabled")
 		}
 		if !intelrdt.IsMBAEnabled() && config.IntelRdt.MemBwSchema != "" {
 			return errors.New("intelRdt.memBwSchema is specified in config, but Intel RDT/MBA is not enabled")
 		}
-
-		if intelrdt.IsCATEnabled() && config.IntelRdt.L3CacheSchema == "" {
-			return errors.New("Intel RDT/CAT is enabled and intelRdt is specified in config, but intelRdt.l3CacheSchema is empty")
-		}
-		if intelrdt.IsMBAEnabled() && config.IntelRdt.MemBwSchema == "" {
-			return errors.New("Intel RDT/MBA is enabled and intelRdt is specified in config, but intelRdt.memBwSchema is empty")
-		}
 	}
 
 	return nil

libcontainer/intelrdt/intelrdt.go

@@ -525,7 +525,12 @@ func (m *intelRdtManager) getIntelRdtPath() (string, error) {
 		return "", err
 	}
 
-	return filepath.Join(rootPath, m.id), nil
+	clos := m.id
+	if m.config.IntelRdt != nil && m.config.IntelRdt.ClosID != "" {
+		clos = m.config.IntelRdt.ClosID
+	}
+
+	return filepath.Join(rootPath, clos), nil
 }
 
 // Applies Intel RDT configuration to the process with the specified pid
@@ -557,12 +562,17 @@ func (m *intelRdtManager) Apply(pid int) (err error) {
 
 // Destroys the Intel RDT 'container_id' group
 func (m *intelRdtManager) Destroy() error {
-	m.mu.Lock()
-	defer m.mu.Unlock()
-	if err := os.RemoveAll(m.GetPath()); err != nil {
-		return err
+	// Don't remove resctrl group if closid has been explicitly specified. The
+	// group is likely externally managed, i.e. by some other entity than us.
+	// There are probably other containers/tasks sharing the same group.
+	if m.config.IntelRdt == nil || m.config.IntelRdt.ClosID == "" {
+		m.mu.Lock()
+		defer m.mu.Unlock()
+		if err := os.RemoveAll(m.GetPath()); err != nil {
+			return err
+		}
+		m.path = ""
 	}
-	m.path = ""
 	return nil
 }
 

libcontainer/specconv/spec_linux.go

@@ -301,6 +301,7 @@ func CreateLibcontainerConfig(opts *CreateOpts) (*configs.Config, error) {
 		}
 		if spec.Linux.IntelRdt != nil {
 			config.IntelRdt = &configs.IntelRdt{
+				ClosID:        spec.Linux.IntelRdt.ClosID,
 				L3CacheSchema: spec.Linux.IntelRdt.L3CacheSchema,
 				MemBwSchema:   spec.Linux.IntelRdt.MemBwSchema,
 			}