Patronus: High-Performance and Protective Remote Memory

RDMA-enabled remote memory (RM) systems are gaining popularity with improved memory utilization and elasticity. However, since it is commonly believed that fine-grained RDMA permission management is impractical, existing RM systems forgo memory protection, an indispensable property in a real-world deployment. In this paper, we propose PATRONUS, an RM system that can simultaneously offer protection and high performance. PATRONUS introduces a fast permission management mechanism by exploiting advanced RDMA hardware features with a set of elaborate software techniques. Moreover, to retain the high performance under exception scenarios (e.g., client failures, illegal access), PATRONUS attaches microsecond-scaled leases to permission and reserves spare RDMA resources for fast recovery. We evaluate PATRONUS over two one-sided data structures and two function-as-a-service (FaaS) applications. The experiment shows that the protection only brings 2.4% to 27.7% overhead among all the workloads and our system performs at most x5.2 than the best competitor.