Book Image

Linux Kernel Programming

By : Kaiwan N. Billimoria
Book Image

Linux Kernel Programming

By: Kaiwan N. Billimoria

Overview of this book

Linux Kernel Programming is a comprehensive introduction for those new to Linux kernel and module development. This easy-to-follow guide will have you up and running with writing kernel code in next-to-no time. This book uses the latest 5.4 Long-Term Support (LTS) Linux kernel, which will be maintained from November 2019 through to December 2025. By working with the 5.4 LTS kernel throughout the book, you can be confident that your knowledge will continue to be valid for years to come. You’ll start the journey by learning how to build the kernel from the source. Next, you’ll write your first kernel module using the powerful Loadable Kernel Module (LKM) framework. The following chapters will cover key kernel internals topics including Linux kernel architecture, memory management, and CPU scheduling. During the course of this book, you’ll delve into the fairly complex topic of concurrency within the kernel, understand the issues it can cause, and learn how they can be addressed with various locking technologies (mutexes, spinlocks, atomic, and refcount operators). You’ll also benefit from more advanced material on cache effects, a primer on lock-free techniques within the kernel, deadlock avoidance (with lockdep), and kernel lock debugging techniques. By the end of this kernel book, you’ll have a detailed understanding of the fundamentals of writing Linux kernel module code for real-world projects and products.
Table of Contents (19 chapters)
1
Section 1: The Basics
6
Writing Your First Kernel Module - LKMs Part 2
7
Section 2: Understanding and Working with the Kernel
10
Kernel Memory Allocation for Module Authors - Part 1
11
Kernel Memory Allocation for Module Authors - Part 2
14
Section 3: Delving Deeper
17
About Packt

Summary

In this chapter, you learned about several areas and facets of the versatile Linux kernel's CPU scheduler. Firstly, you saw how the actual KSE is a thread and not a process, followed by gaining an appreciation of the available scheduling policies that the OS implements. Next, you understood that to support multiple CPUs in a superbly scalable fashion, the kernel powerfully mirrors this with a design that employs one runqueue per CPU core per scheduling class. How to query any given thread's scheduling policy and priority, and deeper details on the internal implementation of the CPU scheduler, were then covered. We focused on how the modern scheduler leverages the modular scheduling classes design, who exactly runs the actual scheduler code and when, and ended with a brief note on the context switch.

The next chapter has you continue on this journey, gaining more insight and details on the workings of the kernel-level CPU scheduler. I suggest you first fully...