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.

2. Code Management

One of the largest initial obstacles to understanding the code is deciding where to start and how to easily manage, browse and get an overview of the overall code structure. If requested on mailing lists, people will provide some suggestions on how to proceed but a comprehensive methodology has to be developed by each developer on their own.

The advice that is frequently offered to new developers is to read books on general operating systems, on Linux specifically, visit the kernel newbies website^2.1 and then read the code, benchmark the kernel and write a few documents. There is a recommended reading list provided on the website but there is no set of recommended tools for analysing and breaking down the code and, while reading the code from beginning to end is admirable, it is hardly the most efficient method of understanding the kernel.

Hence, this section is devoted to describing what tools were used during the course of researching this document to make understanding and managing the code easier and to aid researchers and developers in deciphering the kernel. It begins with a guide to how developers manage their source with patches, revision tools and how developers sometimes develop their own branch which includes their own set of modifications to the main development tree. We then introduce diff and patch in more detail, how to easily browse the code and analyse the flow. We then talk about how to approach the understanding of the VM and how to submit work.

Footnotes

... website^2.1

http://www.kernelnewbies.org