Update FAQs 10.21 and 10.22

[pauamma_gundo.com]

Summary

• remove mentions of cache queue
• introduce laundry queue
• copyedit definition of free memory in FAQ 10.22

PR: 242062

Test Plan

tested with lynx

[debdrup]

Syntactically and lexicographically, this makes sense to me.
As to whether it matters kernel-defined behavior, that's outside my area of expertise.

[markj]

en_US.ISO8859-1/books/faq/book.xml

4029

Let's remove the "in the interrupt or process states" qualifier. It is referring to a mechanism we use in the page allocator to reserve free pages for high-priority allocations, but that is just an implementation detail and no longer has anything to do with the "state" being referred to.

4040

"active or inactive"

4045

Let's replace "whether they are active or inactive" with "regardless of their location in the page queues" or something similar.

4046

s/inactive/laundry/

And perhaps update the description of the inactive queue:

"In most common cases, it is best to think of the laundry queue to be a queue of relatively unused, dirty pages that might or might not be in the process of being written to disk. The inactive queue contains a mix of clean and dirty pages; clean pages near the head of the queue are reclaimed immediately to alleviate a free page shortage, and dirty pages are moved to the laundry queue for deferred processing."

Feel free to reword, this is just a suggestion.

4049

Again let's remove this qualifier, or perhaps even the whole sentence.

4068

Maybe qualify with "some other reserved pages".

[pauamma_gundo.com]

This should address all of markj's comments.

[markj]

The patch looks reasonable to me. Thanks for doing this!

[pauamma_gundo.com]

Thanks for reviewing it. Can a docs committer (I'm not one) take care of it?