Resource recommandation for understanding Linux.

TL;DR: Personally, I recommend to read the book “Understanding the Linux Virtual Memory Manager” and the source code.

Crash course: Linux Kernel Labs provides a quick overview about Linux subsystems.

Eg.

• Memory Management
• Filesystem Management

Detailed learning: the book “Linux Kernel Development” provides a quick introduction to Linux.

Eg.

• Chapter 11. Memory Management
• Chapter 12. The Virtual Filesystem

The book “Understanding the Linux Virtual Memory Manager” provides a more detailed description about memory management in Linux.

Note that the book is a bit out-of-date – the code in it is from Linux 2.x versions. Nevertheless, it serves as a great guide. Also, you can refer to the lastest Linux source code using Bootlin source code browser to have a sense of what current Linux behaves.