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/systemd_linux.go

@@ -0,0 +1,167 @@
+//go:build linux
+// +build linux
+
+package cgroups
+
+import (
+	"context"
+	"fmt"
+	"path/filepath"
+	"strings"
+
+	systemdDbus "github.com/coreos/go-systemd/v22/dbus"
+	"github.com/godbus/dbus/v5"
+	"github.com/opencontainers/runc/libcontainer/configs"
+)
+
+func systemdCreate(resources *configs.Resources, path string, c *systemdDbus.Conn) error {
+	slice, name := filepath.Split(path)
+	slice = strings.TrimSuffix(slice, "/")
+
+	var lastError error
+	for i := 0; i < 2; i++ {
+		properties := []systemdDbus.Property{
+			systemdDbus.PropDescription(fmt.Sprintf("cgroup %s", name)),
+			systemdDbus.PropWants(slice),
+		}
+		pMap := map[string]bool{
+			"DefaultDependencies": false,
+			"MemoryAccounting":    true,
+			"CPUAccounting":       true,
+			"BlockIOAccounting":   true,
+		}
+		if i == 0 {
+			pMap["Delegate"] = true
+		}
+
+		for k, v := range pMap {
+			p := systemdDbus.Property{
+				Name:  k,
+				Value: dbus.MakeVariant(v),
+			}
+			properties = append(properties, p)
+		}
+
+		uMap, sMap, bMap, iMap := resourcesToProps(resources)
+		for k, v := range uMap {
+			p := systemdDbus.Property{
+				Name:  k,
+				Value: dbus.MakeVariant(v),
+			}
+			properties = append(properties, p)
+		}
+
+		for k, v := range sMap {
+			p := systemdDbus.Property{
+				Name:  k,
+				Value: dbus.MakeVariant(v),
+			}
+			properties = append(properties, p)
+		}
+
+		for k, v := range bMap {
+			p := systemdDbus.Property{
+				Name:  k,
+				Value: dbus.MakeVariant(v),
+			}
+			properties = append(properties, p)
+		}
+
+		for k, v := range iMap {
+			p := systemdDbus.Property{
+				Name:  k,
+				Value: dbus.MakeVariant(v),
+			}
+			properties = append(properties, p)
+		}
+
+		ch := make(chan string)
+		_, err := c.StartTransientUnitContext(context.TODO(), name, "replace", properties, ch)
+		if err != nil {
+			lastError = err
+			continue
+		}
+		<-ch
+		return nil
+	}
+	return lastError
+}
+
+/*
+   systemdDestroyConn is copied from containerd/cgroups/systemd.go file, that
+   has the following license:
+
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       https://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+func systemdDestroyConn(path string, c *systemdDbus.Conn) error {
+	name := filepath.Base(path)
+
+	ch := make(chan string)
+	_, err := c.StopUnitContext(context.TODO(), name, "replace", ch)
+	if err != nil {
+		return err
+	}
+	<-ch
+	return nil
+}
+
+func resourcesToProps(res *configs.Resources) (map[string]uint64, map[string]string, map[string][]byte, map[string]int64) {
+	bMap := make(map[string][]byte)
+	// this array is not used but will be once more resource limits are added
+	sMap := make(map[string]string)
+	iMap := make(map[string]int64)
+	uMap := make(map[string]uint64)
+
+	// CPU
+	if res.CpuPeriod != 0 {
+		uMap["CPUQuotaPeriodUSec"] = res.CpuPeriod
+	}
+	if res.CpuQuota != 0 {
+		period := res.CpuPeriod
+		if period == 0 {
+			period = uint64(100000)
+		}
+		cpuQuotaPerSecUSec := uint64(res.CpuQuota*1000000) / period
+		if cpuQuotaPerSecUSec%10000 != 0 {
+			cpuQuotaPerSecUSec = ((cpuQuotaPerSecUSec / 10000) + 1) * 10000
+		}
+		uMap["CPUQuotaPerSecUSec"] = cpuQuotaPerSecUSec
+	}
+
+	// CPUSet
+	if res.CpusetCpus != "" {
+		bits := []byte(res.CpusetCpus)
+		bMap["AllowedCPUs"] = bits
+	}
+	if res.CpusetMems != "" {
+		bits := []byte(res.CpusetMems)
+		bMap["AllowedMemoryNodes"] = bits
+	}
+
+	// Mem
+	if res.Memory != 0 {
+		iMap["MemoryMax"] = res.Memory
+	}
+	if res.MemorySwap != 0 {
+		iMap["MemorySwapMax"] = res.MemorySwap
+	}
+
+	// Blkio
+	if res.BlkioWeight > 0 {
+		uMap["BlockIOWeight"] = uint64(res.BlkioWeight)
+	}
+
+	return uMap, sMap, bMap, iMap
+}