virtcontainers: Rename the cgroups package

To resourcecontrol, and make it consistent with the fact that cgroups
are a Linux implementation of the ResourceController interface.

Fixes: #3601

Signed-off-by: Samuel Ortiz <s.ortiz@apple.com>

src/runtime/virtcontainers/pkg/resourcecontrol/controller.go

@@ -0,0 +1,82 @@
+// Copyright (c) 2021 Apple Inc.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+package resourcecontrol
+
+import (
+	v1 "github.com/containerd/cgroups/stats/v1"
+	"github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/sirupsen/logrus"
+)
+
+var (
+	controllerLogger = logrus.WithField("source", "virtcontainers/pkg/resourcecontrol")
+)
+
+// SetLogger sets up a logger for this pkg
+func SetLogger(logger *logrus.Entry) {
+	fields := controllerLogger.Data
+
+	controllerLogger = logger.WithFields(fields)
+}
+
+// HypervisorType describes an hypervisor type.
+type ResourceControllerType string
+
+const (
+	LinuxCgroups ResourceControllerType = "cgroups"
+)
+
+// String converts an hypervisor type to a string.
+func (rType *ResourceControllerType) String() string {
+	switch *rType {
+	case LinuxCgroups:
+		return string(LinuxCgroups)
+	default:
+		return "Unknown controller type"
+	}
+}
+
+// ResourceController represents a system resources controller.
+// On Linux this interface is implemented through the cgroups API.
+type ResourceController interface {
+	// Type returns the resource controller implementation type.
+	Type() ResourceControllerType
+
+	// The controller identifier, e.g. a Linux cgroups path.
+	ID() string
+
+	// Parent returns the parent controller, on hierarchically
+	// defined resource (e.g. Linux cgroups).
+	Parent() string
+
+	// Delete the controller.
+	Delete() error
+
+	// Stat returns the statistics for the controller.
+	Stat() (*v1.Metrics, error)
+
+	// AddProcess adds a process to a set of controllers.
+	AddProcess(int, ...string) error
+
+	// AddThread adds a process thread to a set of controllers.
+	AddThread(int, ...string) error
+
+	// Update updates the set of resources controlled, based on
+	// an OCI resources description.
+	Update(*specs.LinuxResources) error
+
+	// MoveTo moves a controller to another one.
+	MoveTo(string) error
+
+	// AddDevice adds a device resource to the controller.
+	AddDevice(string) error
+
+	// RemoveDevice removes a device resource to the controller.
+	RemoveDevice(string) error
+
+	// UpdateCpuSet updates the set of controlled CPUs and memory nodes.
+	UpdateCpuSet(string, string) error
+}