[CentOS] memory map

Is there any way to tell what has been "mapped" into memory on linux (C5 
x86_64)?

I am trying to use the "pagein @pagein-impress" command from openoffice 
and it
does not seem to make any difference in speed.

Can I tell if the files have actually been mapped into memory?
Maybe I am not doing something right.

Thanks,

Jerry