vd_capacity_t
vd_capacity_t *vd_cap;
alloc_len = P2ROUNDUP(sizeof (vd_capacity_t), sizeof (uint64_t));
vd_capacity_t vd_cap = { 0 };
if (nbytes != RNDSIZE(vd_capacity_t)) {
RNDSIZE(vd_capacity_t), nbytes);