epoch_tracker_t
epoch_trace_enter(struct thread *td, epoch_t epoch, epoch_tracker_t et,
epoch_tracker_t iet;
epoch_trace_exit(struct thread *td, epoch_t epoch, epoch_tracker_t et,
epoch_tracker_t iet;
_epoch_enter_preempt(epoch_t epoch, epoch_tracker_t et EPOCH_FILE_LINE)
_epoch_exit_preempt(epoch_t epoch, epoch_tracker_t et EPOCH_FILE_LINE)
void _epoch_enter_preempt(epoch_t epoch, epoch_tracker_t et EPOCH_FILE_LINE);
void _epoch_exit_preempt(epoch_t epoch, epoch_tracker_t et EPOCH_FILE_LINE);