On Sat, Mar 24, 2018 at 07:33:53AM +0100, Nguyễn Thái Ngọc Duy wrote:

Previous patches leave lots of holes and padding in this struct. This
patch reorders the members and shrinks the struct down to 80 bytes
(from 136 bytes, before any field shrinking is done) with 16 bits to
spare (and a couple more in in_pack_header_size when we really run out
of bits).

Out of curiosity, did you count this yourself, or did you double-check
with a few compilers to make sure they all produce the same result?

So having read the whole thing now, I think most of my original concerns
have been addressed. I do think readability takes a hit, but it's not
_too_ bad. There are a few things that have become more brittle, but I
can't think of anything on the horizon that would bite us.

-Peff