__create_val_field 4549 kernel/trace/trace_events_hist.c 	return __create_val_field(hist_data, val_idx, file, NULL, field_str, 0);
__create_val_field 4573 kernel/trace/trace_events_hist.c 	return __create_val_field(hist_data, val_idx, file, var_name, expr_str, flags);