Hi Andy,

On Tue, 5 Oct 2021 at 21:14, Andy Shevchenko
[off-list ref] wrote:

quoted

Ok, is there a reason it's not for the ID tables? Does it break something?

It will look ugly. Why we define a table that may or may not be used?
Sounds fishy.

I guess it's a toss up between is the attribute more ugly than #ifdefs
and is the ugliness of either worth it..
Not going to say I have an answer here. :)

On top of that why you should tell linker to waste resources on something
that you may well know beforehand will be thrown away?

That's true but the linker on my machine with 64GB of RAM compiling
for a single core machine with 64MB of RAM doesn't mind too much.

quoted

For what it's worth I think the OF ids are a bit wasteful.

Exactly my point, but fixing one driver of zillions does not solve the issue
in general.

I looked into making OF ids smaller globally. There seems to be 64
bytes wasted from the start for the name and type fields as nothing
uses them as far as I can tell.
Then you have the array for the compatible string which is currently
128 bytes but the longest compatible string in the kernel is less than
64 from what I can tell.
I understand that it's for future proofing etc. Adding a few hacks to
my kernel to remove the unused fields and reduce the size of the
compatible string saved a few tens of K.
Which isn't a lot but might be the difference between the kernel
fitting in a tiny SPI NOR partition or not.

quoted

For some
drivers where there are tons of broken variations they add a few K of
unneeded data. But since everyone now has gigabytes of memory I doubt
they care...

Some actually cares.

Ok.. I might consider pushing my changes to remove unused ids all over
the place then.
drivers/cpufreq/cpufreq-dt-platdev.c is a really good example of
adding ~10K to kernels for no reason.

quoted

I'm working with 64MB. :)

Then I would imagine that you already using as less kernel configuration as
possible and have as many modules as you want for the hardware that might
appear to be connected to that board, right?

I have a minimal config but compiling in macb for the ethernet
compiles in code and ids for stuff like zynq that I could do without.

Then again one driver with 100+
bytes doesn't affect really your case. Disabling, for example PRINTK, will
win much more for you.

It's not *that* bad just yet. :)

Anyhow, thankyou for the interesting discussion. I'll just leave this
in my tree for now so I don't have to see the warning.

Cheers,

Daniel