Raymond:
> 1) move the expensive get_functools_state_by_type() inside the code block that creates new links, so that it won't affect a full cache.

This should be as easy as adding a _functools_state pointer to struct lru_cache_object, init that pointer in lru_cache_new(), and then fetch it from self in infinite_lru_cache_wrapper() and bounded_lru_cache_wrapper(), no? Diff attached.