TDI_IWAIT
#define TD_AWAITING_INTR(td) ((td)->td_inhibitors & TDI_IWAIT)
((td)->td_inhibitors & TDI_IWAIT) != 0 ? "iwait" : "yielding")
#define TD_SET_IWAIT(td) TD_SET_INHIB((td), TDI_IWAIT)
#define TD_CLR_IWAIT(td) TD_CLR_INHIB((td), TDI_IWAIT)