Older trees

The current git history looks too short to tell whether the speed of code
removal follows a "half-life" curve. We still have 58.6% of the git origin
(2.6.12-rc2) code present in the current kernel (it only makes up 30.5% of
the current code because the kernel is almost twice as large now).

Here's a graph showing growth of the kernel, and decline of the original
code:

http://www.kernel.org/pub/linux/kernel/people/aegl/codede...