libcontainer/intelrdt: rm init() from intelrdt.go

Use sync.Once to init Intel RDT when needed for a small speedup to operations which do not require Intel RDT. Simplify IntelRdtManager initialization in LinuxFactory. Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
opencontainers · Oct 16, 2020 · b856cd3 · b856cd3
1 parent 0cc43aa
commit b856cd3
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Showing 3 changed files with 60 additions and 55 deletions.
diff --git a/libcontainer/factory_linux.go b/libcontainer/factory_linux.go
@@ -148,11 +148,16 @@ func RootlessCgroupfs(l *LinuxFactory) error {
 // containers that use the Intel RDT "resource control" filesystem to
 // create and manage Intel RDT resources (e.g., L3 cache, memory bandwidth).
 func IntelRdtFs(l *LinuxFactory) error {
- l.NewIntelRdtManager = func(config *configs.Config, id string, path string) intelrdt.Manager {
- return &intelrdt.IntelRdtManager{
- Config: config,
- Id: id,
- Path: path,
+ intelrdt.InitIntelRdt()
+ if !intelrdt.IsCATEnabled() && !intelrdt.IsMBAEnabled() {
+ l.NewIntelRdtManager = nil
+ } else {
+ l.NewIntelRdtManager = func(config *configs.Config, id string, path string) intelrdt.Manager {
+ return &intelrdt.IntelRdtManager{
+ Config: config,
+ Id: id,
+ Path: path,
+ }
  }
  }
  return nil
@@ -276,7 +281,7 @@ func (l *LinuxFactory) Create(id string, config *configs.Config) (Container, err
  newgidmapPath: l.NewgidmapPath,
  cgroupManager: l.NewCgroupsManager(config.Cgroups, nil),
  }
- if intelrdt.IsCATEnabled() || intelrdt.IsMBAEnabled() {
+ if l.NewIntelRdtManager != nil {
  c.intelRdtManager = l.NewIntelRdtManager(config, id, "")
  }
  c.state = &stoppedState{c: c}
@@ -318,13 +323,13 @@ func (l *LinuxFactory) Load(id string) (Container, error) {
  root: containerRoot,
  created: state.Created,
  }
+ if l.NewIntelRdtManager != nil {
+ c.intelRdtManager = l.NewIntelRdtManager(&state.Config, id, state.IntelRdtPath)
+ }
  c.state = &loadedState{c: c}
  if err := c.refreshState(); err != nil {
  return nil, err
  }
- if intelrdt.IsCATEnabled() || intelrdt.IsMBAEnabled() {
- c.intelRdtManager = l.NewIntelRdtManager(&state.Config, id, state.IntelRdtPath)
- }
  return c, nil
 }
 

diff --git a/libcontainer/intelrdt/intelrdt.go b/libcontainer/intelrdt/intelrdt.go
@@ -187,6 +187,9 @@ var (
  mbaEnabled bool
  // The flag to indicate if Intel RDT/MBA Software Controller is enabled
  mbaScEnabled bool
+
+ // For Intel RDT initialization
+ initOnce sync.Once
 )
 
 type intelRdtData struct {
@@ -195,55 +198,56 @@ type intelRdtData struct {
  pid int
 }
 
-// Check if Intel RDT sub-features are enabled in init()
-func init() {
- // 1. Check if hardware and kernel support Intel RDT sub-features
- flagsSet, err := parseCpuInfoFile("/proc/cpuinfo")
- if err != nil {
- return
- }
-
- // 2. Check if Intel RDT "resource control" filesystem is mounted
- // The user guarantees to mount the filesystem
- if !isIntelRdtMounted() {
- return
- }
-
- // 3. Double check if Intel RDT sub-features are available in
- // "resource control" filesystem. Intel RDT sub-features can be
- // 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 {
- catEnabled = true
- }
- }
- if mbaScEnabled {
- // We confirm MBA Software Controller is enabled in step 2,
- // MBA should be enabled because MBA Software Controller
- // depends on MBA
- mbaEnabled = true
- } else if flagsSet.MBA {
- if _, err := os.Stat(filepath.Join(intelRdtRoot, "info", "MB")); err == nil {
- mbaEnabled = true
+// Check if Intel RDT sub-features are enabled in InitIntelRdt()
+func InitIntelRdt() {
+ initOnce.Do(func() {
+ // 1. Check if hardware and kernel support Intel RDT sub-features
+ flagsSet, err := parseCpuInfoFile("/proc/cpuinfo")
+ if err != nil {
+ return
  }
- }
 
- if flagsSet.MBMTotal || flagsSet.MBMLocal || flagsSet.CMT {
- if _, err := os.Stat(filepath.Join(intelRdtRoot, "info", "L3_MON")); err != nil {
+ // 2. Check if Intel RDT "resource control" filesystem is mounted
+ // The user guarantees to mount the filesystem
+ if !isIntelRdtMounted() {
  return
  }
- enabledMonFeatures, err = getMonFeatures(intelRdtRoot)
- if err != nil {
- return
+
+ // 3. Double check if Intel RDT sub-features are available in
+ // "resource control" filesystem. Intel RDT sub-features can be
+ // 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 {
+ catEnabled = true
+ }
  }
- if enabledMonFeatures.mbmTotalBytes || enabledMonFeatures.mbmLocalBytes {
- mbmEnabled = true
+ if mbaScEnabled {
+ // We confirm MBA Software Controller is enabled in step 2,
+ // MBA should be enabled because MBA Software Controller
+ // depends on MBA
+ mbaEnabled = true
+ } else if flagsSet.MBA {
+ if _, err := os.Stat(filepath.Join(intelRdtRoot, "info", "MB")); err == nil {
+ mbaEnabled = true
+ }
  }
- if enabledMonFeatures.llcOccupancy {
- cmtEnabled = true
+ if flagsSet.MBMTotal || flagsSet.MBMLocal || flagsSet.CMT {
+ if _, err := os.Stat(filepath.Join(intelRdtRoot, "info", "L3_MON")); err != nil {
+ return
+ }
+ enabledMonFeatures, err = getMonFeatures(intelRdtRoot)
+ if err != nil {
+ return
+ }
+ if enabledMonFeatures.mbmTotalBytes || enabledMonFeatures.mbmLocalBytes {
+ mbmEnabled = true
+ }
+ if enabledMonFeatures.llcOccupancy {
+ cmtEnabled = true
+ }
  }
- }
+ })
 }
 
 // Return the mount point path of Intel RDT "resource control" filesysem

diff --git a/utils_linux.go b/utils_linux.go
@@ -13,7 +13,6 @@ import (
  "github.com/opencontainers/runc/libcontainer"
  "github.com/opencontainers/runc/libcontainer/cgroups/systemd"
  "github.com/opencontainers/runc/libcontainer/configs"
- "github.com/opencontainers/runc/libcontainer/intelrdt"
  "github.com/opencontainers/runc/libcontainer/specconv"
  "github.com/opencontainers/runc/libcontainer/utils"
  "github.com/opencontainers/runtime-spec/specs-go"
@@ -57,9 +56,6 @@ func loadFactory(context *cli.Context) (libcontainer.Factory, error) {
  }
 
  intelRdtManager := libcontainer.IntelRdtFs
- if !intelrdt.IsCATEnabled() && !intelrdt.IsMBAEnabled() {
- intelRdtManager = nil
- }
 
  // We resolve the paths for {newuidmap,newgidmap} from the context of runc,
  // to avoid doing a path lookup in the nsexec context. TODO: The binary