Optimal memory-anonymous symmetric deadlock-free mutual exclusion

Zahra Aghazadeh, Damien Imbs, Michel Raynal, Gadi Taubenfeld, Philipp Woelfel

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


The notion of an anonymous shared memory, introduced by Taubenfeld in PODC 2017, considers that processes use different names for the same memory location. As an example, a location name A used by a process p and a location name B A used by another process q can correspond to the very same memory location X, and similarly for the names B used by p and A used by q which may (or may not) correspond to the same memory location Y X. In this context, the PODC paper presented a 2-process symmetric deadlock-free mutual exclusion (mutex) algorithm and a necessary condition on the size m of the anonymous memory for the existence of such an n-process algorithm. This condition states that m must be belongs to M(n) {1} where M(n)= {m: : (1) The present paper presents two optimal deadlock-free symmetric mutual exclusion algorithms for n-process systems where communication is through m registers. The first algorithm, which considers anonymous read/write registers, works for any m which is n and belongs to the set M(n). It follows that this condition on m is both necessary and sufficient for symmetric deadlock-free mutual exclusion in this anonymity context, and this algorithm is optimal with respect to m The second algorithm, which considers anonymous read/modify/write atomic registers, works for any m M(n), which is shown to be necessary and sufficient for anonymous read/modify/write registers. It follows that, when m > 1, m M(n) is a tight characterization of the size of the anonymous shared memory needed to solve deadlock-free mutex, be the registers read/write or read/modify/write.

Original languageEnglish
Title of host publicationPODC 2019 - Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing
PublisherAssociation for Computing Machinery
Number of pages10
ISBN (Electronic)9781450362177
StatePublished - 16 Jul 2019
Externally publishedYes
Event38th ACM Symposium on Principles of Distributed Computing, PODC 2019 - Toronto, Canada
Duration: 29 Jul 20192 Aug 2019

Publication series

NameProceedings of the Annual ACM Symposium on Principles of Distributed Computing


Conference38th ACM Symposium on Principles of Distributed Computing, PODC 2019

Bibliographical note

Publisher Copyright:
© 2019 ACM.


  • Anonymous shared memory
  • Asynchronous system
  • Atomic register
  • Computability
  • Deadlock-freedom
  • Mutual exclusion
  • Read-modify-write register
  • Read-write register


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