Book Image

Mastering Embedded Linux Programming - Third Edition

By : Frank Vasquez, Chris Simmonds
5 (3)
Book Image

Mastering Embedded Linux Programming - Third Edition

5 (3)
By: Frank Vasquez, Chris Simmonds

Overview of this book

If you’re looking for a book that will demystify embedded Linux, then you’ve come to the right place. Mastering Embedded Linux Programming is a fully comprehensive guide that can serve both as means to learn new things or as a handy reference. The first few chapters of this book will break down the fundamental elements that underpin all embedded Linux projects: the toolchain, the bootloader, the kernel, and the root filesystem. After that, you will learn how to create each of these elements from scratch and automate the process using Buildroot and the Yocto Project. As you progress, the book will show you how to implement an effective storage strategy for flash memory chips and install updates to a device remotely once it’s deployed. You’ll also learn about the key aspects of writing code for embedded Linux, such as how to access hardware from apps, the implications of writing multi-threaded code, and techniques to manage memory in an efficient way. The final chapters demonstrate how to debug your code, whether it resides in apps or in the Linux kernel itself. You’ll also cover the different tracers and profilers that are available for Linux so that you can quickly pinpoint any performance bottlenecks in your system. By the end of this Linux book, you’ll be able to create efficient and secure embedded devices using Linux.
Table of Contents (27 chapters)
1
Section 1: Elements of Embedded Linux
10
Section 2: System Architecture and Design Decisions
18
Section 3: Writing Embedded Applications
22
Section 4: Debugging and Optimizing Performance

Summary

Accounting for every byte of memory used in a virtual memory system is just not possible. However, you can find a fairly accurate figure for the total amount of free memory, excluding that taken by buffers and the cache, using the free command. By monitoring it over a period of time and with different workloads, you should become confident that it will remain within a given limit.

When you want to tune memory usage or identify sources of unexpected allocations, there are resources that give more detailed information. For kernel space, the most useful information is in /proc: meminfo, slabinfo, and vmallocinfo.

When it comes to getting accurate measurements for user space, the best metric is PSS,
as shown by smem and other tools. For memory debugging, you can get help from
simple tracers such as mtrace, or you have the heavyweight option of the Valgrind memcheck tool.

If you have concerns about the consequence of an OOM situation, you can fine-tune the allocation mechanism...