[patrec]

In extreme cases you might be able to emulate arena allocation by spawning an external process, create huge object, do some work on it, throw away the process. How viable this is depends on the programming language you are using. In erlang it can work great, because gc is per process (no shared memory) and you can use green-threads; in languages with very grummy GC like python it can also be worth considering[1] even with the cost of spawning a system process. I haven't kept up to date with Net, but my guess would be it's generally not a very attractive strategy.

[1] Refcounting will be instantaneous of course, but if you have a large heap with a lot of objects and GC kicks in you can have very long gc pauses (even if next to nothing will be reclaimed).