After this documentation was released in July 2003, I was approached by Prentice Hall and asked to write a book on the Linux VM under the Bruce Peren's Open Book Series.

The book is available and called simply "Understanding The Linux Virtual Memory Manager". There is a lot of additional material in the book that is not available here, including details on later 2.4 kernels, introductions to 2.6, a whole new chapter on the shared memory filesystem, coverage of TLB management, a lot more code commentary, countless other additions and clarifications and a CD with lots of cool stuff on it. This material (although now dated and lacking in comparison to the book) will remain available although I obviously encourge you to buy the book from your favourite book store :-) . As the book is under the Bruce Perens Open Book Series, it will be available 90 days after appearing on the book shelves which means it is not available right now. When it is available, it will be downloadable from http://www.phptr.com/perens so check there for more information.

To be fully clear, this webpage is not the actual book.

1.2 Thesis Overview

In Chapter 2, I will go into detail on how the code may be managed and deciphered. Three tools will be introduced that are used for the analysis, easy browsing and management of code. The first is a tool called Linux Cross Referencing (LXR) which allows source code to be browsed as a web page with identifiers and functions highlighted as hyperlinks to allow easy browsing. The second is a tool called gengraph which was developed for this project and is used to generate call graphs starting from a particular function with the ability to limit the depth and what functions are displayed. The last is a simple tool for managing kernels and the application of patches. Applying patches manually can be time consuming and the use of version control software such as CVS^1.1 or BitKeeper^1.2 is not always an option. With this tool, a simple file specifies what source to use, what patches to apply and what kernel configuration to use.

In the subsequent chapters, each part of the implementation of the Linux VM will be discussed in detail such as how memory is described in an architecture independent manner, how processes manage their memory, how the specific allocators work and so on. Each will refer to the papers that describe closest the behavior of Linux as well as covering in depth the implementation, the functions used and their call graphs so the reader will have a clear view of how the code is structured. For a detailed examination of the code, the reader is encouraged to consult the companion document.

Footnotes

... CVS^1.1

http://www.cvshome.org/

... BitKeeper^1.2

http://www.bitmover.com