Os Memory Management Questions Medium
The LRU-WSR (Least Recently Used with Working Set Replacement) page replacement algorithm is a combination of the LRU (Least Recently Used) and WSR (Working Set Replacement) algorithms. It aims to improve the efficiency of memory management by considering both the recent usage of pages and the working set of a process.
In the LRU-WSR algorithm, each page in memory is assigned a timestamp indicating the last time it was accessed. When a page needs to be replaced, the algorithm first checks if the page is part of the working set of the process. The working set represents the set of pages that a process is actively using. If the page is part of the working set, it is considered as a candidate for replacement.
Among the pages in the working set, the algorithm selects the page with the oldest timestamp, indicating that it has been accessed least recently. This page is then replaced with the new page that needs to be brought into memory.
If the page to be replaced is not part of the working set, the algorithm falls back to the LRU strategy. It selects the page with the oldest timestamp among all the pages in memory, regardless of whether they are part of the working set or not.
By combining the LRU and WSR strategies, the LRU-WSR algorithm takes into account both the recent usage of pages and the working set of a process. This helps in reducing the number of page faults and improving the overall performance of the memory management system.