Towards O(1) Memory

Since the dawn of computing, memory capacity has been a primary limitation in system design. Forthcoming memory technology such as Intel and Micron's 3D XPoint memory and other technologies may provide far larger memory capacity than ever before. Furthermore, these new memory technologies are inherently persistent and save data across system crashes or power failures. We conjecture that current operating systems are ill-equipped for an environment where there is ample memory. For example, operating systems do substantial work for every page allocated, which adds unnecessary overhead when dealing with terabytes of memory. We suggest that now is the time for a complete rethinking of memory management for both operating systems and language runtimes considering excess memory capacity. We propose a new guiding principle: Order(1) operation, so that memory operations have low constant time independent of size. We describe a concrete proposal of this principle with the idea of file-only memory, in which most dynamic memory allocation is managed with file-system mechanisms rather than common virtual memory mechanisms.