Vault 2016

2016 will be the year of Persistent Memory, and these high speed/capacity, non-volatile memory devices are just around the corner, we’re told. Similar to both current storage and memory devices, NVDIMMs will also be susceptible to developing ‘bad’ locations. Unlike DRAM, these errors will persist across reboots, and have to be handled like we do traditional storage.

With DRAM, if a poison location is read, the CPU takes a machine check exception, and typically reboots, and the poison is cleared. With NVDIMMs, the poison won’t be cleared, and it is likely that the application accessing that location will do so again, causing a reboot loop.

This talk details how we solve this problem and its different manifestations in the Linux kernel, and how we enable userspace applications to become aware of poison blocks and deal with them if they so choose.