Userspace RCU 0.7.5

liburcu is a LGPLv2.1 userspace RCU (read-copy-update) library. This data synchronization library provides read-side access which scales linearly with the number of cores. It does so by allowing multiples copies of a given data structure to live at the same time, and by monitoring the data structure accesses to detect grace periods after which memory reclamation is possible.

liburcu-cds provides efficient data structures based on RCU and lock-free algorithms. Those structures include hash tables, queues, stacks, and doubly-linked lists.

This is the start of a stable-0.7 branch to push important fixes. The master branch development will continue and eventually result in a 0.8.0 release.

Please note that the bug "call_rcu list corruption on teardown" occurs very rarely, only when invoking call_rcu_data_free() for per-cpu or per-thread callback-invocation threads (typically before application exit). The fix for this corruption bug is the same as the fix used in the stable-0.6 branch. This fix is not needed in the master branch, because the issue had been already fixed by moving call_rcu to the new wfcqueue API.

Changelog:
2012-10-12 Userspace RCU 0.7.5
* Fix: call_rcu list corruption on teardown
* Ensure that read-side functions meet 10-line LGPL criterion
* tls-compat.h: document sigaltstack(2) limitation
* urcu: add notice to URCU_TLS() for it is not strictly async-signal-safe
* Document sigaltstack(2) limitation
* Documentation: update LICENSE file

Project website: http://lttng.org/urcu
Download link: http://lttng.org/files/urcu/

Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com