ZRAM if you have no HDD/SSD swap partition.
ZSWAP if you do have a HDD/SSD swap partition.
ZCACHE: It does what ZSWAP does and ALSO compresses and speeds the filesystem page cache. (It is internally much more complicated and is not in the mainline kernel as it is still under development).
J. Clarke, and M. Lapata. Proceedings of the 2007 Joint Conference on Empirical Methods in Natural Language Processing and Computational Natural Language Learning (EMNLP-CoNLL), (2007)
L. Benini, A. Macii, E. Macii, and M. Poncino. ISLPED '99: Proceedings of the 1999 international symposium on Low power electronics and design, page 206--211. New York, NY, USA, ACM, (1999)
D. Abadi, S. Madden, and M. Ferreira. SIGMOD '06: Proceedings of the 2006 ACM SIGMOD international conference on Management of data, page 671--682. New York, NY, USA, ACM, (2006)