Comment 17 for bug 1552680

It's possible to introduce it with a toggle, but I think that if we do that, we do that with the intention of eventually removing the toggle and have it always on. The reason is that the main selling point of adding a DLM is that you can make assumptions in the code that is locked. If the existence of the lock is controlled via config option, you can't really make any assumptions anymore, and the whole thing is useless.