Read-Copy Update (RCU)

RCU is a synchronization mechanism that is used in the Linux kernel to replace some uses of reader-writer locking and reference counting. The concepts behind RCU are quite simple: At its core, RCU is just a way of waiting for things to get done. However, effective use of RCU does require that you think about concurrency in a different way. RCU is only recently being added to university coursework, but fortunately there is quite a bit of documentation available:

• Documentation/RCU in the Linux-kernel source tree.

• A number of [https://lwn.net LWN] articles, including:

  • [http://lwn.net/Articles/262464/ What is RCU, Fundamentally?]

  • [http://lwn.net/Articles/263130/ What is RCU's Usage?]

  • [http://lwn.net/Articles/418853/ The RCU API, 2010 Edition.]

  • [http://lwn.net/Articles/202847/ Sleepable RCU.]

• [http://doi.ieeecomputersociety.org/10.1109/TPDS.2011.159 User-Level Implementations of Read-Copy Update] (freely available [http://www.rdrop.com/users/paulmck/RCU/urcu-main-accepted.2011.08.30a.pdf pre-publication version]). See also the freely available [http://www.computer.org/cms/Computer.org/dl/trans/td/2012/02/extras/ttd2012020375s.pdf supplementary information].

• [http://en.wikipedia.org/wiki/Read-copy-update The wikipedia article].

For additional documentation on RCU, see Documentation/RCU/RTFP.txt in your friendly Linux-kernel source tree.