Access to deleted objects is detected by marking objects deleted and not reclaiming their memory until the containing pages are mostly full of deleted objects,

Access to deleted objects is detected by marking objects deleted and not reclaiming their memory until the containing pages are mostly full of deleted objects, then they relocate still-live objects and unmap the pages. That is, they use MMU tricks but they amortize the MMU cost (otherwise performance would be absolutely abysmal). Note that they still need to rewrite object references, which is a lot like a GC. EDIT: No, sorry, they lazy patch references, though this requires some overhead. Also, this does nothing to protect against leaks. Interesting idea, but too-little-too-late. I think Rust is the better answer for now. EDIT: Great question from the Q&A of the video, "why are you not getting killed by TLB misses?", and the presenter did not know. This is a really important question.