This post details my adventures with the Linux virtual memory subsystem, and my discovery of a creative way to taunt the OOM (out of memory) killer by accumulating memory in the kernel, rather than in userspace.
Keep reading and you’ll learn:
Internal details of the Linux kernel’s demand paging implementation
How to exploit virtual memory to implement highly efficient sparse data structures
What page tables are and how to calculate the memory overhead incurred by them
A cute way to get killed by the OOM killer while appearing to consume very little memory (great for parties)
Congratulations! You just finished developing your first contribution to the Linux kernel, and are excited to submit it. The process for doing so is tricky, with many conventions that the community has developed over time, so here is what I learned after doing so for the first time. This is intended to be a succinct supplement to the official contribution documentation.
Here is everything you need to know to set up a minimal Linux kernel dev environment on Ubuntu 20.04. It works great on small VPS instances, is optimized for a fast development cycle, and allows you to run custom binaries to exercise the specific kernel functionality being developed.
This was a pretty interesting buggy scenario I found while reading the clang-tidy checks. If you’re writing a function that takes a forwarding reference (what looks like an rvalue reference, but whose type is a template argument), you need to be careful to not call std::move on it. You need to make sure to call std::forward instead. Otherwise, you might accidentally trigger a move on an object passed by a caller! This would be confusing, since their object would be moved from, and they never explicitly called std::move on it.