pmap_pvo_pool
pool_put(&pmap_pvo_pool, pvo);
error = pmap_pvo_enter(pm, &pmap_pvo_pool, pvo_head, va, pa, pte_lo, flags);
error = pmap_pvo_enter(pmap_kernel(), &pmap_pvo_pool,
struct pool pmap_pvo_pool; /* pool for pvo entries */
pool_init(&pmap_pvo_pool, sizeof(struct pvo_entry),
pool_setlowat(&pmap_pvo_pool, 1008);