Frankly weird that they were resorting to high level containers for this in the first place. Also, this line struck me as odd

> Big Pineapple uses jemalloc, an allocator designed for multithreaded, allocation-heavy workloads.

jemalloc multithreaded performance is actually poor(ish) compared to other modern allocators, which makes it a weird choice. But even weirder is why they're even using an allocator in the first place compared to a va MAP_ANON | MAP_NORESERVE arena carveout approach? You can also do punning that way too, which I'm not even certain if Rust supports?

I would also have instinctively reached for a large VM reservation to exploit demand paging. I have used that pattern a lot in C++ but not in Rust, so I don't know how difficult it would be to implement there.