PAGE_LLOCK_HASH
mutex_enter(&page_llocks[PAGE_LLOCK_HASH(PP_PAGEROOT(pp))].pad_mutex)
mutex_exit(&page_llocks[PAGE_LLOCK_HASH(PP_PAGEROOT(pp))].pad_mutex)
nidx = PAGE_LLOCK_HASH(PP_PAGEROOT(npp));
oidx = PAGE_LLOCK_HASH(PP_PAGEROOT(opp));