Meta: Transparent memory offloading

ThisMeta blog post by Johannes Weiner and Dan Schatzberg describes a set ofmemory-management changes used there that they call "transparent memoryoffloading".

Transparent Memory Offloading (TMO) is Meta's solution forheterogeneous data center environments. It introduces a new Linuxkernel mechanism that measures the lost work due to resourceshortage across CPU, memory, and I/O in real time. Guided by thisinformation and without any prior application knowledge, TMOautomatically adjusts the amount of memory to offload to aheterogeneous device, such as compressed memory or an SSD.

The article doesn't say where to find the relevant code, not all of whichis in the mainline kernel (and some of which runs in user space).