Re: [GIT PULL 2/2] Kconfig updates for v5.10-rc1

From: Linus Torvalds
Date: Fri Nov 27 2020 - 16:12:37 EST


Just a quick note, because it's been a small annoyance for a while (I
don't think it has anything to do with the 5.10 pull, I'm just
responding to your latest pull request)..

I have "make allmodconfig" taking unnecessarily long, and I finally
started asking myself "what's so expensive here". I'd expect it to be
basically instantaneous on my machine, and it isn't.

And when I looked at it, I noticed that it re-compiled
scripts/kconfig/conf every single time.

For no obvious reason I can see.

Doing a

make --trace allmodconfig

shows a series of

scripts/Makefile.host:112: target 'scripts/kconfig/....o' does not exist

lines, which is silly and wrong (they definitely exist), and I suspect
it's due to some confusion about the build directory or similar.

It's probably obvious to you once you start looking at it.

And yeah, I realize I'm being silly. Doing a "time make allmodconfig"
shows that it takes 1.5s to do. Should I care? No. But I feel that's
an eternity for something that I think should just be instantaneous.

Linus