Suggestions

Suggested Order of Implementation

We suggest the following initial order of implementation:

• Frame table (see section Managing the Frame Table).

  • Change process.c to use your frame table allocator.

  • Do not implement swapping yet. If you run out of frames, fail the allocator or panic the kernel.

  • After this step, your kernel should still pass all the project 2 test cases.

• Supplemental page table and page fault handler (see section Managing the Supplemental Page Table).

  • Change process.c to record the necessary information in the supplemental page table when loading an executable and setting up its stack.

  • Implement loading of code and data segments in the page fault handler.

  • For now, consider only valid accesses.

  • After this step, your kernel should pass all of the project 2 functionality test cases, but only some of the robustness tests.

• From here, you can implement page reclamation on process exit.

• The next step is to implement eviction (see section Managing the Frame Table).

  • Initially you could choose the page to evict randomly.

  • At this point, you need to consider how to manage accessed and dirty bits and aliasing of user and kernel pages.

  • Synchronization is also a concern: how do you deal with it if process A faults on a page whose frame process B is in the process of evicting?

  • Finally, implement a eviction strategy such as the clock algorithm.