What happens to initramfs after boot?

[kitepilot at kitepilot.com]

OK, I did it...
I compiled an all-modules kernel and I am using udev inside my initramfs 
init to find my root partition and boot the system.
It works cool...  :) 

It wasn't easy, and after lots of tries with klibc-1.5, I gave it up and 
went to a straight glibc (2.8-20080929). 

Also, sorting out modules dependencies was a $%#& (challenge  :), so I just 
included every freaking-existing-module-under-the-Sun into my cpio tree.
Along with a bunch of commands and glibc libraries.
That yielded a generous 30MB worth of junk to boot from.
In memory...
Still with me?
Good...   :) 

Now my question is:
Where do those 30MB go to after boot?
Are they released back to the pool or are they held hostage in RAM forever? 

I'm dizzy and crossed-eyed reading kernel documents/messages and I just 
can't come up with a straight answer.
I think I'm gonna puke depmods...   :(
Does anybody know?
ET 

PS: BTW, this is an LFS installation, nothing fancy...