code: func validateResources(hc *container.HostConfig, si *sysinfo.SysInfo) error {
  	// We may not be passed a host config, such as in the case of docker commit
  	if hc == nil {
  		return nil
  	}
  
  	if hc.Resources.CPURealtimePeriod > 0 && !si.CPURealtimePeriod {
  		return fmt.Errorf("Your kernel does not support cgroup cpu real-time period")
  	}
  
  	if hc.Resources.CPURealtimeRuntime > 0 && !si.CPURealtimeRuntime {
  		return fmt.Errorf("Your kernel does not support cgroup cpu real-time runtime")
  	}
  
  	if hc.Resources.CPURealtimePeriod != 0 && hc.Resources.CPURealtimeRuntime != 0 && hc.Resources.CPURealtimeRuntime > hc.Resources.CPURealtimePeriod {
  		return fmt.Errorf("cpu real-time runtime cannot be higher than cpu real-time period")
  	}
  	return nil
  }
docs: // validateResources performs platform specific validation of the resource settings
  // cpu-rt-runtime and cpu-rt-period can not be greater than their parent, cpu-rt-runtime requires sys_nice