Intel RDT: updates according to proposed spec changes.

libcontainer/intelrdt/intelrdt.go

@@ -146,10 +146,11 @@ import (
  */
 
 type Manager struct {
- mu sync.Mutex
- config *configs.Config
- id string
- path string
+ mu sync.Mutex
+ config *configs.Config
+ id string
+ path string
+ directoryCreated bool
 }
 
 // NewManager returns a new instance of Manager, or nil if the Intel RDT
@@ -170,9 +171,10 @@ func NewManager(config *configs.Config, id string, path string) *Manager {
 // is actually available. Used by unit tests that mock intelrdt paths.
 func newManager(config *configs.Config, id string, path string) *Manager {
  return &Manager{
- config: config,
- id: id,
- path: path,
+ config: config,
+ id: id,
+ path: path,
+ directoryCreated: false,
  }
 }
 
@@ -466,6 +468,14 @@ func (m *Manager) Apply(pid int) (err error) {
  }
  }
 
+ // If the directory doesn't exist we need to create it -> it means we also need
+ // to clean it up afterwards. Make a note to the manager.
+ if _, err := os.Stat(path); err != nil {
+ if os.IsNotExist(err) {
+ m.directoryCreated = true
+ }
+ }
+
  if err := os.MkdirAll(path, 0o755); err != nil {
  return newLastCmdError(err)
  }
@@ -482,8 +492,9 @@ func (m *Manager) Apply(pid int) (err error) {
 func (m *Manager) Destroy() error {
  // 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 == "" {
+ // There are probably other containers/tasks sharing the same group. Also
+ // only remove the directory if it was created by us.
+ if m.config.IntelRdt != nil && m.config.IntelRdt.ClosID == "" && m.directoryCreated {
  m.mu.Lock()
  defer m.mu.Unlock()
  if err := os.RemoveAll(m.GetPath()); err != nil {
@@ -589,6 +600,28 @@ func (m *Manager) GetStats() (*Stats, error) {
  return stats, nil
 }
 
+func combineSchemas(l3CacheSchema, memBwSchema string) string {
+ // If both l3CacheSchema and memBwSchema are set and
+ // l3CacheSchema contains a line beginning with "MB:", the
+ // value written to schemata file MUST be the non-"MB:"
+ // line(s) from l3CacheSchema and the line from memBWSchema.
+
+ validLines := make([]string, 0)
+
+ // Split the l3CacheSchema to lines.
+ lines := strings.Split(l3CacheSchema, "\n")
+
+ // Remove the "MB:" lines.
+ for _, line := range lines {
+ if strings.HasPrefix(line, "MB:") {
+ continue
+ }
+ validLines = append(validLines, line)
+ }
+
+ return strings.Join(validLines, "\n") + "\n" + memBwSchema
+}
+
 // Set Intel RDT "resource control" filesystem as configured.
 func (m *Manager) Set(container *configs.Config) error {
  // About L3 cache schema:
@@ -649,7 +682,8 @@ func (m *Manager) Set(container *configs.Config) error {
 
  // Write a single joint schema string to schemata file
  if l3CacheSchema != "" && memBwSchema != "" {
- if err := writeFile(path, "schemata", l3CacheSchema+"\n"+memBwSchema); err != nil {
+ schemata := combineSchemas(l3CacheSchema, memBwSchema)
+ if err := writeFile(path, "schemata", schemata); err != nil {
  return err
  }
  }

libcontainer/intelrdt/intelrdt_test.go

@@ -67,6 +67,46 @@ func TestIntelRdtSetMemBwSchema(t *testing.T) {
  }
 }
 
+func TestIntelRdtSetCombinedSchema(t *testing.T) {
+ helper := NewIntelRdtTestUtil(t)
+
+ // Test filtering out the "MB:"" line in l3CacheSchema.
+
+ const (
+ schemaBefore = "MB:0=20;1=70"
+ memBwSchema = "MB:0=70;1=20"
+ l3CacheSchema = "MB:0=80;1=10\nL3:0=f0;1=f"
+ combinedSchemaAfter = "L3:0=f0;1=f\nMB:0=70;1=20"
+ )
+
+ helper.writeFileContents(map[string]string{
+ "schemata": schemaBefore + "\n",
+ })
+
+ helper.config.IntelRdt.MemBwSchema = memBwSchema
+ helper.config.IntelRdt.L3CacheSchema = l3CacheSchema
+ intelrdt := newManager(helper.config, "", helper.IntelRdtPath)
+ if err := intelrdt.Set(helper.config); err != nil {
+ t.Fatal(err)
+ }
+
+ tmpStrings, err := getIntelRdtParamString(helper.IntelRdtPath, "schemata")
+ if err != nil {
+ t.Fatalf("Failed to parse file 'schemata' - %s", err)
+ }
+
+ readValues := strings.Split(tmpStrings, "\n")
+ expectedValues := strings.Split(combinedSchemaAfter, "\n")
+
+ if readValues[0] != expectedValues[0] {
+ t.Fatal("Got the wrong value for L3 cache, set 'schemata' failed.")
+ }
+
+ if readValues[1] != expectedValues[1] {
+ t.Fatal("Got the wrong value for MemBW, set 'schemata' failed.")
+ }
+}
+
 func TestIntelRdtSetMemBwScSchema(t *testing.T) {
  helper := NewIntelRdtTestUtil(t)