AVM: application-level virtual memory

Virtual memory (VM) is a notoriously complicated abstraction to implement, and is hard to change, specialize , or replace. Although a certain degree of exi-bility is achieved by user-level pagers, the control they provide is limited: they leave much of the VM system xed in the kernel, unreachable by the application. As applications become more diverse and the opportunity cost of bad memory policies grows, it is essential for applications to have more control over the VM abstraction. In this position paper, we motivate and describe a VM system that is implemented completely at the application level. To the best of our knowlege this system is the rst complete example of application-level virtual memory (AVM). AVM allows applications to easily specialize, modify, or even replace the VM abstractions ooered. For example, on architectures with software TLB management, applications can even select their own page-table structures. In addition, AVM simpliies the OS kernel, since the kernel only multi-plexes and does not abstract physical memory. A prototype AVM system is implemented for Aegis, an experimental exokernel.