vm_page_trysbusy
if (vm_page_trysbusy(tbp->b_pages[j]) == 0)
if (vm_page_trysbusy(m) == 0) {
if (!vm_page_trysbusy(fs->m)) {
if (vm_page_trysbusy(tm) == 0) {
return (vm_page_trysbusy(m));
int vm_page_trysbusy(vm_page_t m);