[Documentation] Page Table Layout diagrams

Hello all.  In an effort to understand how the page tables are laid out
across various architectures I put together some diagrams.  I have
posted them on the linux-mm wiki: http://linux-mm.org/PageTableStructure
and I hope they will be useful to others.  

Just to make sure I am not spreading misinformation, could a few of you
experts take a quick look at the three diagrams I've got finished so far
and point out any errors I have made?  Thanks.

-- 
Adam Litke - (agl at us.ibm.com)
IBM Linux Technology Center