On Fri, May 03, 2024 at 04:09:40PM +0200, Thomas Weißschuh wrote:

Hey Joel,

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quoted

# Motivation
As I read it, the motivation for these constification efforts are:
1. It provides increased safety: Having things in .rodata section reduces the
   attack surface. This is especially relevant for structures that have function
   pointers (like ctl_table); having these in .rodata means that these pointers
   always point to the "intended" function and cannot be changed.
2. Compiler optimizations: This was just a comment in the patchsets that I have
   mentioned ([3,4,5]). Do you know what optimizations specifically? Does it
   have to do with enhancing locality for the data in .rodata? Do you have other
   specific optimizations in mind?

I don't know about anything that would make it faster.
It's more about safety and transmission of intent to API users,
especially callback implementers.

Noted.

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# Show the move
I created [8] because there is no easy way to validate which objects made it
into .rodata. I ran [8] for your Dec 2nd patcheset [7] and there are less in
.rodata than I expected (the results are in [9]) Why is that? Is it something
that has not been posted to the lists yet? 

Constifying the APIs only *allows* the actual table to be constified
themselves.
Then each table definition will have to be touched and "const" added.

That is what I thought. thx for clarifying.

See patches 17 and 18 in [7] for two examples.

Some tables in net/ are already "const" as the static definitions are
never registered themselves but only their copies are.

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best

-- 

Joel Granados