People seem to think that writing a garbage collector is really hard, a deep magic understood by a few great sages and Hans Boehm (et al). Well it’s not. In fact, it’s rather straight forward. I claim that the hardest part in writing a GC is writing the memory allocator, which is as hard to write as it is to look up the malloc example in K&R.
A few important things to note before we begin. First, our code will be dependent on the Linux kernel. Not GNU/Linux, but the Linux kernel. Secondly, our code will be 32-bit and not one bit more. Thirdly. Please don’t use this code. I did not intend for it to be wholly correct and there may be subtle bugs I did not catch. Regardless, the ideas themselves are still correct. Now, let’s get started.