Summary: Built­in Coloring for
Highly­Concurrent Doubly­Linked Lists
(Extended Abstract)
Hagit Attiya and Eshcar Hillel
Department of Computer Science, Technion
Abstract. This paper presents a novel approach for lock­free implementations
of concurrent data structures, based on dynamically maintaining a coloring of
the data structure's items. Roughly speaking, the data structure's operations are
implemented by acquiring virtual locks on several items of the data structure and
then making the changes atomically; this simpli£es the design and provides clean
functionality. The virtual locks are managed with CAS or DCAS primitives, and
helping is used to guarantee progress; virtual locks are acquired according to a
coloring order that decreases the length of waiting chains and increases concur­
rency. Coming back full circle, the legality of the coloring is preserved by having
operations correctly update the colors of the items they modify.
The bene£ts of the scheme are demonstrated with new nonblocking implemen­
tations of doubly­linked list data structures: A DCAS­based implementation of
a doubly­linked list allowing insertions and removals anywhere, and CAS­based
implementations in which removals are allowed only at the ends of the list (inser­
tions can occur anywhere).

Source: Attiya, Hagit - Department of Computer Science, Technion, Israel Institute of Technology

Collections: Computer Technologies and Information Sciences