Merge pull request #50072 from squall0gd/squall0gd/hugepages_support

Automatic merge from submit-queue

Hugetlbfs support based on empty dir volume plugin

**What this PR does / why we need it**: Support for huge pages in empty dir volume plugin. More information about hugepages can be found [here](https://www.kernel.org/doc/Documentation/vm/hugetlbpage.txt)

Feature track issue: kubernetes/enhancements#275

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
Support for Huge pages in empty_dir volume plugin
[Huge pages](https://www.kernel.org/doc/Documentation/vm/hugetlbpage.txt) can now be used with empty dir volume plugin.
```

pkg/api/types.go

@@ -681,8 +681,9 @@ type EmptyDirVolumeSource struct {
 type StorageMedium string
 
 const (
-	StorageMediumDefault StorageMedium = ""       // use whatever the default is for the node
-	StorageMediumMemory  StorageMedium = "Memory" // use memory (tmpfs)
+	StorageMediumDefault   StorageMedium = ""          // use whatever the default is for the node
+	StorageMediumMemory    StorageMedium = "Memory"    // use memory (tmpfs)
+	StorageMediumHugePages StorageMedium = "HugePages" // use hugepages
 )
 
 // Protocol defines network protocols supported for things like container ports.

pkg/api/validation/validation.go

@@ -394,6 +394,9 @@ func validateVolumeSource(source *api.VolumeSource, fldPath *field.Path, volName
 				allErrs = append(allErrs, field.Forbidden(fldPath.Child("emptyDir").Child("sizeLimit"), "SizeLimit field must be a valid resource quantity"))
 			}
 		}
+		if !utilfeature.DefaultFeatureGate.Enabled(features.HugePages) && source.EmptyDir.Medium == api.StorageMediumHugePages {
+			allErrs = append(allErrs, field.Forbidden(fldPath.Child("emptyDir").Child("medium"), "HugePages medium is disabled by feature-gate for EmptyDir volumes"))
+		}
 	}
 	if source.HostPath != nil {
 		if numVolumes > 0 {

pkg/api/validation/validation_test.go

@@ -2757,6 +2757,28 @@ func TestValidateVolumes(t *testing.T) {
 	} else if errs[0].Type != field.ErrorTypeDuplicate {
 		t.Errorf("expected error type %v, got %v", field.ErrorTypeDuplicate, errs[0].Type)
 	}
+
+	// Validate HugePages medium type for EmptyDir when HugePages feature is enabled/disabled
+	hugePagesCase := api.VolumeSource{EmptyDir: &api.EmptyDirVolumeSource{Medium: api.StorageMediumHugePages}}
+
+	// Enable alpha feature HugePages
+	err := utilfeature.DefaultFeatureGate.Set("HugePages=true")
+	if err != nil {
+		t.Errorf("Failed to enable feature gate for HugePages: %v", err)
+	}
+	if errs := validateVolumeSource(&hugePagesCase, field.NewPath("field").Index(0), "working"); len(errs) != 0 {
+		t.Errorf("Unexpected error when HugePages feature is enabled.")
+	}
+
+	// Disable alpha feature HugePages
+	err = utilfeature.DefaultFeatureGate.Set("HugePages=false")
+	if err != nil {
+		t.Errorf("Failed to disable feature gate for HugePages: %v", err)
+	}
+	if errs := validateVolumeSource(&hugePagesCase, field.NewPath("field").Index(0), "failing"); len(errs) == 0 {
+		t.Errorf("Expected error when HugePages feature is disabled got nothing.")
+	}
+
 }
 
 func TestAlphaHugePagesIsolation(t *testing.T) {

pkg/volume/empty_dir/BUILD

@@ -19,12 +19,14 @@ go_library(
         "//conditions:default": [],
     }),
     deps = [
+        "//pkg/api/v1/helper:go_default_library",
         "//pkg/util/mount:go_default_library",
         "//pkg/util/strings:go_default_library",
         "//pkg/volume:go_default_library",
         "//pkg/volume/util:go_default_library",
         "//vendor/github.com/golang/glog:go_default_library",
         "//vendor/k8s.io/api/core/v1:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/api/resource:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/types:go_default_library",
     ] + select({
@@ -51,6 +53,7 @@ go_test(
             "//pkg/volume/testing:go_default_library",
             "//pkg/volume/util:go_default_library",
             "//vendor/k8s.io/api/core/v1:go_default_library",
+            "//vendor/k8s.io/apimachinery/pkg/api/resource:go_default_library",
             "//vendor/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
             "//vendor/k8s.io/apimachinery/pkg/types:go_default_library",
             "//vendor/k8s.io/client-go/util/testing:go_default_library",

pkg/volume/empty_dir/empty_dir.go

@@ -23,10 +23,12 @@ import (
 
 	"github.com/golang/glog"
 	"k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
+	v1helper "k8s.io/kubernetes/pkg/api/v1/helper"
 	"k8s.io/kubernetes/pkg/util/mount"
-	"k8s.io/kubernetes/pkg/util/strings"
+	stringsutil "k8s.io/kubernetes/pkg/util/strings"
 	"k8s.io/kubernetes/pkg/volume"
 	volumeutil "k8s.io/kubernetes/pkg/volume/util"
 )
@@ -56,7 +58,7 @@ const (
 )
 
 func getPath(uid types.UID, volName string, host volume.VolumeHost) string {
-	return host.GetPodVolumeDir(uid, strings.EscapeQualifiedNameForDisk(emptyDirPluginName), volName)
+	return host.GetPodVolumeDir(uid, stringsutil.EscapeQualifiedNameForDisk(emptyDirPluginName), volName)
 }
 
 func (plugin *emptyDirPlugin) Init(host volume.VolumeHost) error {
@@ -104,9 +106,11 @@ func (plugin *emptyDirPlugin) NewMounter(spec *volume.Spec, pod *v1.Pod, opts vo
 
 func (plugin *emptyDirPlugin) newMounterInternal(spec *volume.Spec, pod *v1.Pod, mounter mount.Interface, mountDetector mountDetector, opts volume.VolumeOptions) (volume.Mounter, error) {
 	medium := v1.StorageMediumDefault
+
 	if spec.Volume.EmptyDir != nil { // Support a non-specified source as EmptyDir.
 		medium = spec.Volume.EmptyDir.Medium
 	}
+
 	return &emptyDir{
 		pod:             pod,
 		volName:         spec.Name(),
@@ -159,8 +163,9 @@ type mountDetector interface {
 type storageMedium int
 
 const (
-	mediumUnknown storageMedium = 0 // assume anything we don't explicitly handle is this
-	mediumMemory  storageMedium = 1 // memory (e.g. tmpfs on linux)
+	mediumUnknown   storageMedium = 0 // assume anything we don't explicitly handle is this
+	mediumMemory    storageMedium = 1 // memory (e.g. tmpfs on linux)
+	mediumHugepages storageMedium = 2 // hugepages
 )
 
 // EmptyDir volumes are temporary directories exposed to the pod.
@@ -221,6 +226,8 @@ func (ed *emptyDir) SetUpAt(dir string, fsGroup *int64) error {
 		err = ed.setupDir(dir)
 	case v1.StorageMediumMemory:
 		err = ed.setupTmpfs(dir)
+	case v1.StorageMediumHugepages:
+		err = ed.setupHugepages(dir)
 	default:
 		err = fmt.Errorf("unknown storage medium %q", ed.medium)
 	}
@@ -257,6 +264,67 @@ func (ed *emptyDir) setupTmpfs(dir string) error {
 	return ed.mounter.Mount("tmpfs", dir, "tmpfs", nil /* options */)
 }
 
+// setupHugepages creates a hugepage mount at the specified directory.
+func (ed *emptyDir) setupHugepages(dir string) error {
+	if ed.mounter == nil {
+		return fmt.Errorf("memory storage requested, but mounter is nil")
+	}
+	if err := ed.setupDir(dir); err != nil {
+		return err
+	}
+	// Make SetUp idempotent.
+	medium, isMnt, err := ed.mountDetector.GetMountMedium(dir)
+	if err != nil {
+		return err
+	}
+	// If the directory is a mountpoint with medium hugepages, there is no
+	// work to do since we are already in the desired state.
+	if isMnt && medium == mediumHugepages {
+		return nil
+	}
+
+	pageSizeMountOption, err := getPageSizeMountOptionFromPod(ed.pod)
+	if err != nil {
+		return err
+	}
+
+	glog.V(3).Infof("pod %v: mounting hugepages for volume %v", ed.pod.UID, ed.volName)
+	return ed.mounter.Mount("nodev", dir, "hugetlbfs", []string{pageSizeMountOption})
+}
+
+// getPageSizeMountOptionFromPod retrieves pageSize mount option from Pod's resources
+// and validates pageSize options in all containers of given Pod.
+func getPageSizeMountOptionFromPod(pod *v1.Pod) (string, error) {
+	pageSizeFound := false
+	pageSize := resource.Quantity{}
+	// In some rare cases init containers can also consume Huge pages.
+	containers := append(pod.Spec.Containers, pod.Spec.InitContainers...)
+	for _, container := range containers {
+		// We can take request because limit and requests must match.
+		for requestName := range container.Resources.Requests {
+			if v1helper.IsHugePageResourceName(requestName) {
+				currentPageSize, err := v1helper.HugePageSizeFromResourceName(requestName)
+				if err != nil {
+					return "", err
+				}
+				// PageSize for all volumes in a POD are equal, except for the first one discovered.
+				if pageSizeFound && pageSize.Cmp(currentPageSize) != 0 {
+					return "", fmt.Errorf("multiple pageSizes for huge pages in a single PodSpec")
+				}
+				pageSize = currentPageSize
+				pageSizeFound = true
+			}
+		}
+	}
+
+	if !pageSizeFound {
+		return "", fmt.Errorf("hugePages storage requested, but there is no resource request for huge pages.")
+	}
+
+	return fmt.Sprintf("pageSize=%s", pageSize.String()), nil
+
+}
+
 // setupDir creates the directory with the default permissions specified by the perm constant.
 func (ed *emptyDir) setupDir(dir string) error {
 	// Create the directory if it doesn't already exist.
@@ -318,9 +386,14 @@ func (ed *emptyDir) TearDownAt(dir string) error {
 	if err != nil {
 		return err
 	}
-	if isMnt && medium == mediumMemory {
-		ed.medium = v1.StorageMediumMemory
-		return ed.teardownTmpfs(dir)
+	if isMnt {
+		if medium == mediumMemory {
+			ed.medium = v1.StorageMediumMemory
+			return ed.teardownTmpfsOrHugetlbfs(dir)
+		} else if medium == mediumHugepages {
+			ed.medium = v1.StorageMediumHugepages
+			return ed.teardownTmpfsOrHugetlbfs(dir)
+		}
 	}
 	// assume StorageMediumDefault
 	return ed.teardownDefault(dir)
@@ -336,7 +409,7 @@ func (ed *emptyDir) teardownDefault(dir string) error {
 	return nil
 }
 
-func (ed *emptyDir) teardownTmpfs(dir string) error {
+func (ed *emptyDir) teardownTmpfsOrHugetlbfs(dir string) error {
 	if ed.mounter == nil {
 		return fmt.Errorf("memory storage requested, but mounter is nil")
 	}
@@ -350,7 +423,7 @@ func (ed *emptyDir) teardownTmpfs(dir string) error {
 }
 
 func (ed *emptyDir) getMetaDir() string {
-	return path.Join(ed.plugin.host.GetPodPluginDir(ed.pod.UID, strings.EscapeQualifiedNameForDisk(emptyDirPluginName)), ed.volName)
+	return path.Join(ed.plugin.host.GetPodPluginDir(ed.pod.UID, stringsutil.EscapeQualifiedNameForDisk(emptyDirPluginName)), ed.volName)
 }
 
 func getVolumeSource(spec *volume.Spec) (*v1.EmptyDirVolumeSource, bool) {

pkg/volume/empty_dir/empty_dir_linux.go

@@ -27,7 +27,10 @@ import (
 )
 
 // Defined by Linux - the type number for tmpfs mounts.
-const linuxTmpfsMagic = 0x01021994
+const (
+	linuxTmpfsMagic     = 0x01021994
+	linuxHugetlbfsMagic = 0x958458f6
+)
 
 // realMountDetector implements mountDetector in terms of syscalls.
 type realMountDetector struct {
@@ -48,6 +51,8 @@ func (m *realMountDetector) GetMountMedium(path string) (storageMedium, bool, er
 	glog.V(5).Infof("Statfs_t of %v: %+v", path, buf)
 	if buf.Type == linuxTmpfsMagic {
 		return mediumMemory, !notMnt, nil
+	} else if buf.Type == linuxHugetlbfsMagic {
+		return mediumHugepages, !notMnt, nil
 	}
 	return mediumUnknown, !notMnt, nil
 }