Suitable users for the API?

We had hazard pointers in BIND 9 for a brief moment and we found out two things:

1. It interacted badly with plugins that created more threads (our implementation needed static array per-thread) which might not be a problem for kernel (and/or kernel already has mechanisms for hot plugging CPUs)
2. It was not needed at all as there were better algorithms for what we were using hazptr ;)

So, I am wondering if you already have identified specific places where hazptrs would help in the kernel?