Modern processors make use of several levels of parallel cache memory within them, in order to provide a very significant speedup when working on memory (we briefly touched upon this in Chapter 8, Kernel Memory Allocation for Module Authors – Part 1, in the Allocating slab memory section). We realize that modern CPUs do not really read and write RAM directly; no, when the software indicates that a byte of RAM is to be read starting at some address, the CPU actually reads several bytes – a whole cacheline of bytes (typically 64 bytes) from the starting address into all the CPU caches (say, L1, L2, and L3: levels 1, 2, and 3). This way, accessing the next few elements of sequential memory results in a tremendous speedup as it's first checked for in the caches (first in L1, then L2, then L3, and a cache hit becomes likely). The reason it's (much) faster is simple: accessing CPU cache...
Linux Kernel Programming
By :
Linux Kernel Programming
By:
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)
Preface
Section 1: The Basics
Free Chapter
Kernel Workspace Setup
Building the 5.x Linux Kernel from Source - Part 1
Building the 5.x Linux Kernel from Source - Part 2
Writing Your First Kernel Module - LKMs Part 1
Writing Your First Kernel Module - LKMs Part 2
Section 2: Understanding and Working with the Kernel
Kernel Internals Essentials - Processes and Threads
Memory Management Internals - Essentials
Kernel Memory Allocation for Module Authors - Part 1
Kernel Memory Allocation for Module Authors - Part 2
The CPU Scheduler - Part 1
The CPU Scheduler - Part 2
Section 3: Delving Deeper
Kernel Synchronization - Part 1
Kernel Synchronization - Part 2
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