clone --bare 2.6.24.y with --reference linus.git too big?

Hello,

I did today a bare clone of the 2.6.24.y tree of the Linux kernel.

I instructed git to use a local mirror of Linus's tree, but the clone ended up downloading over 40MB of data:

$ git clone --bare --reference /.src/kernel/linus.git/ \
    git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-2.6.24.y.git \
    2.6.24.y.git
Initialized empty Git repository in /media/stuff/src/kernel/2.6.24.y.git/
remote: Counting objects: 15483, done.
remote: Compressing objects: 100% (14747/14747), done.
remote: Total 15483 (delta 1795), reused 5236 (delta 632)
Receiving objects: 100% (15483/15483), 46.30 MiB | 317 KiB/s, done.
Resolving deltas: 100% (1795/1795), done.

I expected a much smaller download, as the difference between the heads of both trees are only a few patches (2.6.24 -> 2.6.24.2).

My git is at version 1.5.4.1.99.g3b933.