Learn

• Build yourself a Linux

Perfs

• Linux profiling with Perf

Kernel

• Linux Kernel Explained with a comic 2017-04-30
• Why upgrading your Linux Kernel will make your customers much happier 2012-03-01

Memory

• Kmalloc Internals: Exploring Linux Kernel Memory Allocation
• What every programmer should know about memory, Part 1

Security, Hardening

• 20 Linux Server Hardening Security Tips 2009