Willy,
 I've literally been running this patch in my tree now for 18 months,
and have never seen any issues. However back when I posted it
originally, Luis reported that it caused failures on xfstest

  * generic/095
  * generic/741

although I still have no idea how that could happen. I've looked at
the patch occasionally over the months I've been carrying it, trying
to figure out how it could possibly matter, and have never figured it
out.

I'm not planning on moving it to my mainline tree now either, but I
decided I might as well at least repost it to see if somebody else has
any interest or comments on it. The impetus for this patch is
obviously from your posting back in early 2024 about some real user
that did a lot of really small reads. It still sounds like a very odd
load to me, but apparently there was a good real-life reason for it.

I still think this patch actually looks quite nice - which surprised
me when I wrote it originally. I started out writing it as a "let's
see what this hacky thing results in", but it didn't turn out very
hacky at all.

And it looks ridiculously good on some strange small-read benchmarks,
although I say that purely from memory, since I've long since lost the
code that tested this. Now it's been "tested" purely by virtue of
basically being something I've been running on my own machine for a
long time.

Anyway, feel free to ignore it. I can keep carrying this patch in my
local tree forever or until it actually causes more conflicts than I
feel comfortable keeping around. But so far in the last 18+ months it
has never caused any real pain (I have my own tree that contains a few
random patches for other reasons anyway, although lately this has
actually been the biggest of that little lot).

             Linus