Linux Device Drivers Development

How does the TLB work?

On virtual memory access, the CPU walks through the TLB, trying to find the virtual page number of the page that is being accessed. This step is called TLB lookup. When a TLB entry is found (a match occurs), you say there is a TLB hit and the CPU just keeps running and uses the PFN found in the TLB entry to calculate the target physical address. There is no page fault when a TLB hit occurs. As you can see, as long as a translation can be found in the TLB, virtual memory access will be as fast as physical access. If no TLB entry is found (no match occurs), you say there is a TLB miss.

On a TLB miss event, there are two possibilities, depending on the processor type; TLB miss events can be handled by the software, or ...