FlashVM: Revisiting the Virtual Memory Hierarchy

Flash memory is the largest change to storage in recent history. To date, most research has focused on integrating flash as persistent storage in file systems, with little emphasis on virtual memory paging. However, the VM architecture in most of the commodity operating systems is heavily customized for using disks through software layering, request clustering, and prefetching. We revisit the VM hierarchy in light of flash memory and identify mechanisms that inhibit utilizing its full potential. We find that software overhead for a page fault can be as high as the latency to read a page from flash, and that swap systems are overly tuned towards the characteristics of disks. Based on this study, we propose a new system design, FlashVM, that pages directly to flash memory, avoids unnecessary disk-based optimizations, and orders page writes to flash memory without any firmware support. With flash prices dropping exponentially and speeds improving, we argue that FlashVM proves to be a muc...

• Type: Conference
• Year: 2009
• Where: HOTOS
• Authors: Mohit Saxena, Michael M. Swift
• Keywords: Flash Memory, HOTOS 2009, Operating System, Virtual Memory, Virtual Memory Paging