AMAP
#define amap_flags(AMAP) ((AMAP)->am_flags)
#define amap_refs(AMAP) ((AMAP)->am_ref)
#define amap_lock(AMAP, RWLT) rw_enter((AMAP)->am_lock, (RWLT))
#define amap_unlock(AMAP) rw_exit((AMAP)->am_lock)
p->p_p->ps_acflag |= AMAP;
BIT(AMAP, 'M');