ORC: Increasing Cloud Memory Density via Object Reuse with Capabilities


Vasily A. Sartakov, Lluís Vilanova, and Munir Geden, Imperial College London; David Eyers, University of Otago; Takahiro Shinagawa, The University of Tokyo; Peter Pietzuch, Imperial College London


Cloud environments host many tenants, and typically there is substantial overlap between the application binaries and libraries executed by tenants. Thus, memory de-duplication can increase memory density by allocating memory for shared binaries only once. Existing de-duplication approaches, however, either rely on a shared OS to de-deduplicate binary objects, which provides unacceptably weak isolation; or exploit hypervisor-based de-duplication at the level of memory pages, which is blind to the semantics of the objects to be shared.

We describe Object Reuse with Capabilities (ORC), which supports the fine-grained sharing of binary objects between tenants, while isolating tenants strongly through a small trusted computing base (TCB). ORC uses hardware support for memory capabilities to isolate tenants, which permits shared objects to be accessible to multiple tenants safely. Since ORC shares binary objects within a single address space through capabilities, it uses a new relocation type to create per-tenant state when loading shared objects. ORC supports the loading of objects by an untrusted guest, outside of its TCB, only verifying the safety of the loaded data. Our experiments show that ORC achieves a higher memory density with a lower overhead than hypervisor-based de-deduplication.

OSDI '23 Open Access Sponsored by
King Abdullah University of Science and Technology (KAUST)

Open Access Media

USENIX is committed to Open Access to the research presented at our events. Papers and proceedings are freely available to everyone once the event begins. Any video, audio, and/or slides that are posted after the event are also free and open to everyone. Support USENIX and our commitment to Open Access.

@inproceedings {288632,
author = {Vasily A. Sartakov and Llu{\'\i}s Vilanova and Munir Geden and David Eyers and Takahiro Shinagawa and Peter Pietzuch},
title = {{ORC}: Increasing Cloud Memory Density via Object Reuse with Capabilities},
booktitle = {17th USENIX Symposium on Operating Systems Design and Implementation (OSDI 23)},
year = {2023},
isbn = {978-1-939133-34-2},
address = {Boston, MA},
pages = {573--587},
url = {https://www.usenix.org/conference/osdi23/presentation/sartakov},
publisher = {USENIX Association},
month = jul

Presentation Video