fix: allow more powershell command running at same time

pkg/azureutils/azure_disk_utils.go

@@ -88,8 +88,8 @@ var (
 		{Mode: csi.VolumeCapability_AccessMode_MULTI_NODE_MULTI_WRITER},
 	}
 
-	// lock mutex for RunPowerShellCommand
-	mutex = &sync.Mutex{}
+	wg  sync.WaitGroup
+	sem = make(chan struct{}, 3)
 )
 
 type ManagedDiskParameters struct {
@@ -832,14 +832,18 @@ func SetKeyValueInMap(m map[string]string, key, value string) {
 }
 
 func RunPowershellCmd(command string, envs ...string) ([]byte, error) {
-	// only one powershell command can be executed at a time to avoid OOM
-	mutex.Lock()
-	defer mutex.Unlock()
+	// acquire a semaphore to limit the number of concurrent operations
+	sem <- struct{}{}
+	defer func() { <-sem }()
 
 	cmd := exec.Command("powershell", "-Mta", "-NoProfile", "-Command", command)
 	cmd.Env = append(os.Environ(), envs...)
 	klog.V(6).Infof("Executing command: %q", cmd.String())
-	return cmd.CombinedOutput()
+	output, err := cmd.CombinedOutput()
+
+	// signal the completion of the operation
+	wg.Done()
+	return output, err
 }
 
 // GenerateVolumeName returns a PV name with clusterName prefix. The function