Flexible memory management

EDIC candidacy exam
Exam president: Prof. James Larus
Thesis advisor: Prof. Edouard Bugnion
Co-examiner: Prof. Willy Zwaenepoel

Abstract
Modern applications incorporate code from various, sometimes unverified, sources. Public APIs, external libraries, and software
frameworks are nowadays at the heart of most applications. As a result, both trusted and un- trusted code cohabit within an
application, henceforth requiring fine-grained isolation and protection mechanisms at boundaries known only to the application'##s
developer. At the same time, modern applications strive for performance, which often entails to manage resources in a way that
follows the application'##s logic. Unfortunately, mainstream operating systems expose rigid general pur- pose abstractions that often
limit performance, flexibility, and functionalities of applications. Moreover, by failing to separate resource protection from management,
kernels are responsible for functionalities vital to the application, such as access to the network or virtual memory management, thus
making them an overpowered single point of failure. At a time when more and more applications are deployed over cloud services,
entrusting the kernel, and more generally any privileged software, with such critical functionalities is not only inefficient, but also a risk.
In this paper, we study solutions that re-define the respective responsibilities of the kernel and the application, giving back its freedom
to the latter. We will focus on memory management and present solutions that rely on hardware, flexible kernel design, and modern
software techniques. Haven leverages the SGX intel extension to shield a guest system from an untrusted host. The exokernel
operating system allows application-level management of physical resources. Unikernels are compile-time specialized standalone
kernels for single purpose appliances deployed over cloud platforms. Finally, understanding the arguments and solutions presented in
these papers, I propose my research topic that relates to resource management and the improvement of kernel'##s role and
abstractions to better suit modern applications needs.

Background papers

• Exokernel: An operating system architecture for application-level resource management, D.R. Engler, M.f. Kaashoek, J. O’Toole Jr.
• Unikernels: library operating systems for the cloud, Anil Madhavapeddy et. al.
• Shielding Applications from an Untrusted Cloud with Haven, Andrew Baumann, Marcus Peinado, Galen Hunt