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libct/intelrdt: add Root() #3239

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Oct 11, 2021
Merged

libct/intelrdt: add Root() #3239

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48 changes: 23 additions & 25 deletions libcontainer/intelrdt/intelrdt.go
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Original file line number Diff line number Diff line change
Expand Up @@ -185,10 +185,6 @@ const (
)

var (
// The absolute root path of the Intel RDT "resource control" filesystem
intelRdtRoot string
intelRdtRootLock sync.Mutex

// The flag to indicate if Intel RDT/CAT is enabled
catEnabled bool
// The flag to indicate if Intel RDT/MBA is enabled
Expand All @@ -215,9 +211,10 @@ func featuresInit() {
return
}

// 2. Check if Intel RDT "resource control" filesystem is mounted
// The user guarantees to mount the filesystem
if !isIntelRdtMounted() {
// 2. Check if Intel RDT "resource control" filesystem is available.
// The user guarantees to mount the filesystem.
root, err := Root()
if err != nil {
return
}

Expand All @@ -226,7 +223,7 @@ func featuresInit() {
// selectively disabled or enabled by kernel command line
// (e.g., rdt=!l3cat,mba) in 4.14 and newer kernel
if flagsSet.CAT {
if _, err := os.Stat(filepath.Join(intelRdtRoot, "info", "L3")); err == nil {
if _, err := os.Stat(filepath.Join(root, "info", "L3")); err == nil {
catEnabled = true
}
}
Expand All @@ -236,15 +233,15 @@ func featuresInit() {
// depends on MBA
mbaEnabled = true
} else if flagsSet.MBA {
if _, err := os.Stat(filepath.Join(intelRdtRoot, "info", "MB")); err == nil {
if _, err := os.Stat(filepath.Join(root, "info", "MB")); err == nil {
mbaEnabled = true
}
}
if flagsSet.MBMTotal || flagsSet.MBMLocal || flagsSet.CMT {
if _, err := os.Stat(filepath.Join(intelRdtRoot, "info", "L3_MON")); err != nil {
if _, err := os.Stat(filepath.Join(root, "info", "L3_MON")); err != nil {
return
}
enabledMonFeatures, err = getMonFeatures(intelRdtRoot)
enabledMonFeatures, err = getMonFeatures(root)
if err != nil {
return
}
Expand Down Expand Up @@ -282,10 +279,16 @@ func findIntelRdtMountpointDir(f io.Reader) (string, error) {
return mi[0].Mountpoint, nil
}

// Gets the root path of Intel RDT "resource control" filesystem
func getIntelRdtRoot() (string, error) {
intelRdtRootLock.Lock()
defer intelRdtRootLock.Unlock()
// For Root() use only.
var (
intelRdtRoot string
rootMu sync.Mutex
)

// Root returns the Intel RDT "resource control" filesystem mount point.
func Root() (string, error) {
rootMu.Lock()
defer rootMu.Unlock()

if intelRdtRoot != "" {
return intelRdtRoot, nil
Expand All @@ -309,11 +312,6 @@ func getIntelRdtRoot() (string, error) {
return intelRdtRoot, nil
}

func isIntelRdtMounted() bool {
_, err := getIntelRdtRoot()
return err == nil
}

type cpuInfoFlags struct {
CAT bool // Cache Allocation Technology
MBA bool // Memory Bandwidth Allocation
Expand Down Expand Up @@ -405,7 +403,7 @@ func writeFile(dir, file, data string) error {
func getL3CacheInfo() (*L3CacheInfo, error) {
l3CacheInfo := &L3CacheInfo{}

rootPath, err := getIntelRdtRoot()
rootPath, err := Root()
if err != nil {
return l3CacheInfo, err
}
Expand Down Expand Up @@ -435,7 +433,7 @@ func getL3CacheInfo() (*L3CacheInfo, error) {
func getMemBwInfo() (*MemBwInfo, error) {
memBwInfo := &MemBwInfo{}

rootPath, err := getIntelRdtRoot()
rootPath, err := Root()
if err != nil {
return memBwInfo, err
}
Expand Down Expand Up @@ -468,7 +466,7 @@ func getMemBwInfo() (*MemBwInfo, error) {

// Get diagnostics for last filesystem operation error from file info/last_cmd_status
func getLastCmdStatus() (string, error) {
rootPath, err := getIntelRdtRoot()
rootPath, err := Root()
if err != nil {
return "", err
}
Expand Down Expand Up @@ -517,7 +515,7 @@ func IsMBAScEnabled() bool {

// Get the path of the clos group in "resource control" filesystem that the container belongs to
func (m *intelRdtManager) getIntelRdtPath() (string, error) {
rootPath, err := getIntelRdtRoot()
rootPath, err := Root()
if err != nil {
return "", err
}
Expand Down Expand Up @@ -601,7 +599,7 @@ func (m *intelRdtManager) GetStats() (*Stats, error) {
defer m.mu.Unlock()
stats := newStats()

rootPath, err := getIntelRdtRoot()
rootPath, err := Root()
if err != nil {
return nil, err
}
Expand Down