Paging

Question

In multi-level paging, a big page table is divided into smaller pages and for those pages (of main page table) a new page table is created. So what be basically did is broke down the main page table into small pieces (usually so to reduce the size of parts to page size). But, the overall size of the main page table remain same, right? Then what actually is the benefit of multilevel paging?

Answer 1

The thing is we cannot have a partial page table in memory. By breaking down of the page tables, for the inner levels, we only need to load so many page tables as the memory requirement of a given process. This is how multi-level paging saves memory. If a process use all available memory, then multi-level and single-level paging will have same memory requirement.

Comments

Thanks @arjun sir. Now I understood it.