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Linux Internals for Engineers

What the kernel actually does for you: processes, scheduling, memory, the VFS, namespaces and cgroups, and the strace/perf workflow for explaining why your service behaves the way it does.

9 lessons

Course Q&A

Processes, Scheduling, and Memory

How a program becomes a running process, how the kernel shares CPU time, and how virtual memory and the OOM killer really work.

  1. 01What the Kernel Does When You Run a Programfork, execve, ELF loading, and the syscall boundary — the machinery behind `./server` actually starting.30mOpen
  2. 02Scheduling, Nice, and Why Load Average Isn't CPURunqueues, vruntime, nice values, and the D-state tasks that inflate load without burning a cycle.30mOpen
  3. 03Virtual Memory, the Page Cache, and the OOM KillerWhy `free` shows nothing free, how the page cache works, and how the kernel picks which process dies.35mMembers

The VFS, Filesystems, and Kernel State

Why everything is a file, how /proc and /sys expose kernel internals, and why your writes are not durable until you ask.

  1. 01The VFS: Why Everything Is a FileInodes, dentries, and file descriptors — the single abstraction behind files, sockets, pipes, and epoll.30mMembers
  2. 02Parsing /proc and /sys: Reading Kernel Stateprocfs, sysfs, sysctl knobs, and PSI — the kernel's built-in API, plus the secrets it leaks.35mMembers
  3. 03I/O, the Page Cache, and fsync: When Writes Are Durablewrite() is a promise, not a fact — dirty pages, writeback throttling, and the fsync recipe that survives power loss.35mMembers

Containers and Kernel Diagnosis

Namespaces and cgroups under the hood, then the strace and perf workflow for diagnosing real production behavior.

  1. 01Namespaces and cgroups: The Container PrimitivesEight namespaces for what you see, cgroup limits for what you get — build a container with one command.40mPremium
  2. 02strace: Reading a Process's Conversation with the KernelThe syscall-level debugging tool that solves 'won't start', 'hung', and 'slow' — and its sharp edges.35mPremium
  3. 03perf, eBPF, and Why Your Service Behaves the Way It DoesOn-CPU vs off-CPU diagnosis, perf stat/record/top, and the checklist for real production mysteries.40mPremium