how to change load address.

In our 4.x systems tHE shared libraries seem to load themselves at 
around 2G. which makes it hard to mmap
objects that are big if they need to span that address range.

I've looked around a bit in -currnet as well,
 but can't see if there is a way to change where the libraries are loaded..
I'd prefer to try move them up by 500MB to give me ore contiguous space 
below..

anyone know off the top of their head if we can do this?