Skip to content

Commit

Permalink
Intel RDT: updates according to proposed spec changes.
Browse files Browse the repository at this point in the history
There are two proposed clarifications to the OCI spec.

The first item specifies that the L3CacheSchema line filtering needs to
happen only when both MemBw and L3Cache schemas are specified.

The second item specifies that the subdirectory needs to be deleted.
Runc already does that, but the clarification adds for directory removal
only if the directory was created by us.

Signed-off-by: Ismo Puustinen <[email protected]>
  • Loading branch information
ipuustin committed May 2, 2023
1 parent 5a9266b commit d34c05a
Show file tree
Hide file tree
Showing 2 changed files with 84 additions and 10 deletions.
54 changes: 44 additions & 10 deletions libcontainer/intelrdt/intelrdt.go
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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,
}
}

Expand Down Expand Up @@ -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)
}
Expand All @@ -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 {
Expand Down Expand Up @@ -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:
Expand Down Expand Up @@ -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
}
}
Expand Down
40 changes: 40 additions & 0 deletions libcontainer/intelrdt/intelrdt_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -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)

Expand Down

0 comments on commit d34c05a

Please sign in to comment.