Understanding the Linux Kernel, 3rd Edition

Overview of the Book

To make life easier, Chapter 1, Introduction, presents a general picture of what is inside a Unix kernel and how Linux competes against other well-known Unix systems.

The heart of any Unix kernel is memory management. Chapter 2, Memory Addressing, explains how 80 × 86 processors include special circuits to address data in memory and how Linux exploits them.

Processes are a fundamental abstraction offered by Linux and are introduced in Chapter 3, Processes. Here we also explain how each process runs either in an unprivileged User Mode or in a privileged Kernel Mode. Transitions between User Mode and Kernel Mode happen only through well-established hardware mechanisms called interrupts and exceptions. These are introduced in Chapter 4, Interrupts and Exceptions.

In many occasions, the kernel has to deal with bursts of interrupt signals coming from different devices and processors. Synchronization mechanisms are needed so that all these requests can be serviced in an interleaved way by the kernel: they are discussed in Chapter 5, Kernel Synchronization, for both uniprocessor and multiprocessor systems.

One type of interrupt is crucial for allowing Linux to take care of elapsed time; further details can be found in Chapter 6, Timing Measurements.

Chapter 7, Process Scheduling, explains how Linux executes, in turn, every active process in the system so that all of them can progress toward their completions.

Next we focus again on memory. Chapter 8, Memory Management, describes ...