LTTng is closely related to liburcu (now on http://urcu.so/).
It provides lockless datastructures for screaming fast concurrency on multicore machines. You will be pleasantly surprised by the concurrent hash-map implementation that comes with it [1].
In the event LGPL is too restrictive, there's also concurrencykit (http://concurrencykit.org/), which provides similar mechanisms (both for concurrent memory reclamation and various datastructures built on top).