Re: [GIT PULL] bitmap patches for v6.8

[Linus Torvalds]

So I've left this to be my last pull request, because I hate how our
header files are growing, and this part:

 include/linux/find.h | 301 ++++++++++++++++++++++++++++++-
 1 file changed, 297 insertions(+), 4 deletions(-)

in particular.

Nobody includes <linux/find.h> directly, but indirectly pretty much
*every* single kernel C file includes it.

Looking at some basic stats of my dependency files in my tree, 4426 of
4526 object files (~98%) depend on find.h because they get it through
*some* path that ends up with bitmap.h -> find.h.

And honestly, the number of files that actually want the new functions
is basically just a tiny handful. It's also not obvious how useful
those optimizations are, considering that a lot of the loops are
*tiny*. I looked at a few cases, and the size of the bitmap it was
iterating over was often in the 2-4 range, sometimes (like
RTW89_TXCH_NUM) 13, etc.

In radio-shark, you replaced a loop like this

        for (i = 0; i < 2; i++) {

with that for_each_test_and_clear_bit(), and it *really* isn't clear
that it was worth it. It sure wasn't performance-critical to begin
with.

In general, if an "optimization" doesn't have any performance numbers
attached to it, is it an optimization at all?

So I finally ended up pulling this, but after looking at the patch I
went "this is adding more lines than it removes, has no performance
numbers, and grows a core header file that is included by absolutely
everything by a third".

. and then I decided to just unpull it again.

                  Linus