zthr_iscancelled
arc_adjust_needed = !zthr_iscancelled(arc_adjust_zthr) &&
if (zthr_iscancelled(zthr))
extern boolean_t zthr_iscancelled(zthr_t *t);
if (zthr_iscancelled(zthr)) {
if (zthr_iscancelled(zthr))