About technique of reading codes

Now, I'm reading codes of Xen which is composed of hundreds of thousands of lines.
With firefox , its bookmark function and sticky note plugin for it, I read HTML generated from source codes by Gnu global.


This method is useful to do reverse resolution.
For example, if I think "Where are codes about page fault?", I can find the part by scoping out my bookmarks about the codes.


But it doesn't give whole picture to me.
Woom, should I use "Hira method" ;-) ?