One difficulty in implementing a working set memory management strategy is that when a process requests a new page, it is difficult to determine whether that process is transitioning to a new working set or is expanding its current working set. In the first case it is better for the memory manager to replace one of the process’s pages; in the latter it is better for the memory manager to increase the process’s page frame allocation. How might a memory manager decide which case is appropriate?

What will be an ideal response?

The process changing to a new working set will stop referencing pages in the previous
working set. The process expanding its working set will continue referencing recently referenced
pages as well as the new pages. The memory manager can observe this behavior and
adjust the working set size accordingly.