vm_page_drop
if (vm_page_drop(p, VPRC_OBJREF) == VPRC_OBJREF) {
dropped = (vm_page_drop(m, VPRC_OBJREF) == VPRC_OBJREF);
return (vm_page_drop(m, VPRC_OBJREF) == VPRC_OBJREF);
dropped = vm_page_drop(mold, VPRC_OBJREF) == VPRC_OBJREF;
old = vm_page_drop(m, 1);
old = vm_page_drop(m, VPRC_BLOCKED);