podman cgroup enhancement

currently, setting any sort of resource limit in a pod does nothing. With the newly refactored creation process in c/common, podman ca now set resources at a pod level
meaning that resource related flags can now be exposed to podman pod create.

cgroupfs and systemd are both supported with varying completion. cgroupfs is a much simpler process and one that is virtually complete for all resource types, the flags now just need to be added. systemd on the other hand
has to be handeled via the dbus api meaning that the limits need to be passed as recognized properties to systemd. The properties added so far are the ones that podman pod create supports as well as `cpuset-mems` as this will
be the next flag I work on.

Signed-off-by: Charlie Doern <cdoern@redhat.com>

vendor/github.com/containers/common/pkg/cgroups/cpu_linux.go

@@ -0,0 +1,100 @@
+//go:build linux
+// +build linux
+
+package cgroups
+
+import (
+	"os"
+	"path/filepath"
+	"strconv"
+
+	"github.com/opencontainers/runc/libcontainer/cgroups"
+	"github.com/opencontainers/runc/libcontainer/cgroups/fs"
+	"github.com/opencontainers/runc/libcontainer/cgroups/fs2"
+	"github.com/opencontainers/runc/libcontainer/configs"
+	"github.com/pkg/errors"
+)
+
+type linuxCPUHandler struct {
+	CPU fs.CpuGroup
+}
+
+func getCPUHandler() *linuxCPUHandler {
+	return &linuxCPUHandler{}
+}
+
+// Apply set the specified constraints
+func (c *linuxCPUHandler) Apply(ctr *CgroupControl, res *configs.Resources) error {
+	if ctr.cgroup2 {
+		man, err := fs2.NewManager(ctr.config, filepath.Join(cgroupRoot, ctr.config.Path))
+		if err != nil {
+			return err
+		}
+		return man.Set(res)
+	}
+	path := filepath.Join(cgroupRoot, CPU, ctr.config.Path)
+	return c.CPU.Set(path, res)
+}
+
+// Create the cgroup
+func (c *linuxCPUHandler) Create(ctr *CgroupControl) (bool, error) {
+	if ctr.cgroup2 {
+		return false, nil
+	}
+	return ctr.createCgroupDirectory(CPU)
+}
+
+// Destroy the cgroup
+func (c *linuxCPUHandler) Destroy(ctr *CgroupControl) error {
+	return rmDirRecursively(ctr.getCgroupv1Path(CPU))
+}
+
+// Stat fills a metrics structure with usage stats for the controller
+func (c *linuxCPUHandler) Stat(ctr *CgroupControl, m *cgroups.Stats) error {
+	var err error
+	cpu := cgroups.CpuStats{}
+	if ctr.cgroup2 {
+		values, err := readCgroup2MapFile(ctr, "cpu.stat")
+		if err != nil {
+			return err
+		}
+		if val, found := values["usage_usec"]; found {
+			cpu.CpuUsage.TotalUsage, err = strconv.ParseUint(cleanString(val[0]), 10, 64)
+			if err != nil {
+				return err
+			}
+			cpu.CpuUsage.UsageInKernelmode *= 1000
+		}
+		if val, found := values["system_usec"]; found {
+			cpu.CpuUsage.UsageInKernelmode, err = strconv.ParseUint(cleanString(val[0]), 10, 64)
+			if err != nil {
+				return err
+			}
+			cpu.CpuUsage.TotalUsage *= 1000
+		}
+	} else {
+		cpu.CpuUsage.TotalUsage, err = readAcct(ctr, "cpuacct.usage")
+		if err != nil {
+			if !os.IsNotExist(errors.Cause(err)) {
+				return err
+			}
+			cpu.CpuUsage.TotalUsage = 0
+		}
+		cpu.CpuUsage.UsageInKernelmode, err = readAcct(ctr, "cpuacct.usage_sys")
+		if err != nil {
+			if !os.IsNotExist(errors.Cause(err)) {
+				return err
+			}
+			cpu.CpuUsage.UsageInKernelmode = 0
+		}
+		cpu.CpuUsage.PercpuUsage, err = readAcctList(ctr, "cpuacct.usage_percpu")
+		if err != nil {
+			if !os.IsNotExist(errors.Cause(err)) {
+				return err
+			}
+			cpu.CpuUsage.PercpuUsage = nil
+		}
+	}
+	m.CpuStats = cpu
+	return nil
+}