vm_reserv
struct vm_reserv;
typedef struct vm_reserv *vm_reserv_t;
LIST_HEAD(, vm_reserv) rvq; /* list of reservations */
struct vm_reserv *rv;
size = count * sizeof(struct vm_reserv);
TAILQ_ENTRY(vm_reserv) partpopq; /* (d, r) per-domain queue. */
LIST_ENTRY(vm_reserv) objq; /* (o, r) object queue */
TAILQ_HEAD(vm_reserv_queue, vm_reserv);
struct vm_reserv marker; /* (d, s) scan marker/lock */