/**
  * Check config cache is in sync with config
  * @param W3_Config $config
  * @param SelfTestExceptions $exs
  **/
 private function notify_config_cache_not_writeable($config, $exs)
 {
     try {
         $config->validate_cache_actual();
     } catch (Exception $ex) {
         // we could just create cache folder, so try again
         $config->load(true);
         try {
             $config->validate_cache_actual();
         } catch (Exception $ex) {
             $exs->push(new SelfTestFailedException('<strong>W3 Total Cache Error:</strong> ' . $ex->getMessage()));
         }
     }
 }