Normal setups or just SMP?
> two processes one repeatedly allocating a 4Mb file mmap()ing it
> writing it to disk in a tight loop. One continually opening and
> ftruncate()ing the mmap file as the write is being done.
Huh? Like this?
1: mmap(), write 4MB
2: open(), ftruncate() - and close() or not?
> o Make all the inline's __inline__
No, "inline" is easy to read and takes less horizontal space.
The compiler must support this keyword, and many do.
The kernel is not, was not, and will never be ANSI C.
ANSI C does not include assembly or macro parameters either.
It is best to make the code readable, and 4 '_'s is ugly.