Re: [PATCH v5] Documentation/mm: Initial page table documentation

["Fabio M. De Francesco" <fmdefrancesco@gmail.com>]

On lunedì 19 giugno 2023 10:16:56 CEST Linus Walleij wrote:
> On Sun, Jun 18, 2023 at 3:16 PM Fabio M. De Francesco
> 
> <fmdefrancesco@gmail.com> wrote:
> > I am writing to express my dissent regarding the proposal to add basic
> > information about the role of hierarchical (multi-level) page tables in
> > mapping virtual memory to physical page frames.

[...]
 
> Assuming that newcomers to the Linux kernel have formal academic
> background or specifically operating system education is a bit thick
> IMO, suffice to read pages 108-111 of Glyn Moody's book
> "Rebel Code" about the background of the network maintainer.
> There are a whole bunch of random people attracted to Linux
> development.

Linus,

I must admit that I have had a change of heart regarding the necessity of this 
documentation.

This change came about after reading Jon's reply, as well as your own.

However, it wasn't just because of the two of you. It was mainly due to my 
conversations with some colleagues I work with, who hold M.Sc. degrees in 
Computer Science. 

Despite not having a formal background in CS or CE myself, I have taken the 
time to self-teach the subject matter, which I expected them to be well-versed 
in.

To my surprise, they only have a vague understanding of page tables and the 
fact that processes use addresses that may not correspond to physical 
locations. That's about it!

Hence, I now fully support your initiative and want to express my gratitude 
for undertaking this task.

The only thing I would prefer not to see is the historical reference to the 
first implementation of hierarchical page tables. After all, many concepts 
implemented in Linux are derived or adapted from existing knowledge or 
implementations in other kernels. However, I can also understand why you 
prefer to have it as an introduction to the subject.

Once again thanks,

Fabio