[compute/copy-on-write]: Add a new quiz about Transparent Huge Pages

[robertmercea]

Prerequisite Checklist

• Read the contribution guidelines regarding submitting new changes to the project;
• Tested your changes against relevant architectures and platforms;
• Updated relevant documentation (if needed).

Description of changes

• Change NUM_PAGES to 256 in the fork-faults guide to avoid Transparent Huge Pages (THP) being triggered
  • Previously, the number was set to 1024, which triggered the THP mechanism
  • The students would have only seen 2 page faults from the parent program instead of the expected 1024 (as per the course material), which was counterintuitive
• Create a new quiz about THP
  • Added explanations about THP
  • Included external resources for further reading
• Add the new quiz in config.yaml

[teodutu]

THP is legit, but not always enabled by default. You'd have to configure them in: /sys/kernel/mm/transparent_hugepage/hugepages-<size>/enabled.

For example, my configs are:

$ cat /sys/kernel/mm/transparent_hugepage/hugepages-2048kB/enabled 
always inherit madvise [never]

Which means they're disabled. So I suggest you add instructions to enable THP of various sizes and then have students re-run the faults demo to see the differences. Also add this link, it explains how they affect the TLB: https://docs.kernel.org/admin-guide/mm/transhuge.html.

[robertmercea]

I've added instructions to enable THP as requested. Further explanations about THP have been added in hopes of encouraging students to do the bonus task, or at least to have a better understanding of the concept.
I've also mentioned that the sudo commands that enable THP only affect their system temporarily, knowing that it might be a deterrent for those who do not wish to tinker too much with their devices.