Facebook Developing "OOMD" For Out-of-Memory User-Space Linux Daemon

While the Linux kernel has its own out-of-memory (OOM) killer when system memory becomes over-committed, Facebook developers have been developing their own user-space based solution for handling this situation.

Facebook developers feel that the kernel's OOM killer is in adequate so they have been developing OOMD as the Out of Memory Daemon. OOMD is designed to be deterministic, faster, and offer more flexibility that the kernel code. The open-source daemon is triggered when the system is under memory pressure and can be configured for certain thresholds, can be controlled on a per-cgroup basis, and is more configurable about the events that should take place when hitting out-of-memory events.

The user-space OOMD is also believed to be faster at reacting to OOM events than the kernel killer. Facebook has run into these memory pressure situations on their servers at Facebook and thus developed OOMD to more gracefully handle such situations.

Facebook's Daniel Xu will be talking about OOMD at the Open-Source Summit Europe tomorrow in Edinburgh. But if you can't make it there are the slides (PDF) already available. The OOMD project is hosted on GitHub under the GPLv2 license.