manager: simplify createContainer

The code to initialize perf collector is almost the same between cgroup
v1 and v2, the only difference is how we get cgroup path. Since now
GetCgroupPath is v2 ready, we can use it, and thus unify these two
cases.

This commit is best reviewed with --ignore-space-change.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

cmd/internal/container/mesos/factory_test.go

@@ -19,8 +19,6 @@ import (
 
 	mesos "github.com/mesos/mesos-go/api/v1/lib"
 	"github.com/stretchr/testify/assert"
-
-	containerlibcontainer "github.com/google/cadvisor/container/libcontainer"
 )
 
 func TestIsContainerName(t *testing.T) {

manager/manager.go

@@ -47,7 +47,6 @@ import (
 	"github.com/google/cadvisor/watcher"
 
 	"github.com/opencontainers/runc/libcontainer/cgroups"
-	"github.com/opencontainers/runc/libcontainer/cgroups/fs2"
 
 	"k8s.io/klog/v2"
 	"k8s.io/utils/clock"
@@ -937,15 +936,7 @@ func (m *manager) createContainerLocked(containerName string, watchSource watche
 		return err
 	}
 
-	if cgroups.IsCgroup2UnifiedMode() {
-		if m.includedMetrics.Has(container.PerfMetrics) {
-			perfCgroupPath := path.Join(fs2.UnifiedMountpoint, containerName)
-			cont.perfCollector, err = m.perfManager.GetCollector(perfCgroupPath)
-			if err != nil {
-				klog.Errorf("Perf event metrics will not be available for container %q: %v", containerName, err)
-			}
-		}
-	} else {
+	if !cgroups.IsCgroup2UnifiedMode() {
 		devicesCgroupPath, err := handler.GetCgroupPath("devices")
 		if err != nil {
 			klog.Warningf("Error getting devices cgroup path: %v", err)
@@ -955,15 +946,15 @@ func (m *manager) createContainerLocked(containerName string, watchSource watche
 				klog.V(4).Infof("GPU metrics may be unavailable/incomplete for container %s: %s", cont.info.Name, err)
 			}
 		}
-		if m.includedMetrics.Has(container.PerfMetrics) {
-			perfCgroupPath, err := handler.GetCgroupPath("perf_event")
+	}
+	if m.includedMetrics.Has(container.PerfMetrics) {
+		perfCgroupPath, err := handler.GetCgroupPath("perf_event")
+		if err != nil {
+			klog.Warningf("Error getting perf_event cgroup path: %q", err)
+		} else {
+			cont.perfCollector, err = m.perfManager.GetCollector(perfCgroupPath)
 			if err != nil {
-				klog.Warningf("Error getting perf_event cgroup path: %q", err)
-			} else {
-				cont.perfCollector, err = m.perfManager.GetCollector(perfCgroupPath)
-				if err != nil {
-					klog.Errorf("Perf event metrics will not be available for container %q: %v", containerName, err)
-				}
+				klog.Errorf("Perf event metrics will not be available for container %q: %v", containerName, err)
 			}
 		}
 	}