@unpublished{PaulEMcKenney2008HierarchicalRCU ,Author="Paul E. McKenney" ,Title="Hierarchical {RCU}" ,month="November" ,day="3" ,year="2008" ,note="Available: \url{http://lwn.net/Articles/305782/} [Viewed November 6, 2008]" ,annotation=" RCU with combining-tree-based grace-period detection, permitting it to handle thousands of CPUs. " }