Anything that uses a JIT necessarily uses this "obscure low-level feature", including any program implemented in one of many programming languages. Forcing such programs onto the heavy processor makes no sense; there just needs to be a way to properly clear the cache.
On https://news.ycombinator.com/item?id=12483698 I wrote a better idea how this might be implemented without causing this problem. Nevertheless even if we use my first, worse interface this should not be a problem: Spawn a thread that does the lowlevel stuff, sync it and after that run the JITted code.
