when a virtual address needs to be translated into a physical address, the tlb is searched first. if a match is found (a "tlb hit"), the physical address is returned and memory access can continue. however, if there is no match (called a "tlb miss"), the memory management unit, or the operating system tlb miss handler, will typically look up the address mapping in the page table to see whether a mapping exists (a "page walk"). if one exists, it is written back to the tlb (this must be done, as the hardware accesses memory through the tlb in a virtual memory system), and the faulting instruction is restarted (this may happen in parallel as well). this subsequent translation will find a tlb hit, and the memory access will continue.