The FamFS file-system being developed by Micron hopes to go upstream for Linux in "early-ish 2026".
For around two years already Micron has been working on FamFS as a new file-system that is special purpose and designed for fabric-attached memory (FAM) needs such as with CXL servers. FamFS over the past year was ported to FUSE for largely operating in user-space but some kernel changes remain.
John Groves of Micron who also serves on the CXL Software & Systems working group presented on FamFS at Linux Plumbers Conference this week in Tokyo, Japan.
The current hope is that FamFS will be able to go upstream in "early-ish 2026" and that as of Linux 6.18 the FamFS patches are now fully working with other kernel changes made.
Again, the focus is just on fabric-attached memory with FamFS not aiming to be any general purpose file-system or the like.
Some feature/roadmap plans for FamFS include interleaved file support, proper software-based cache coherency, pNFS integration, and other improvements.
Those wishing to learn more about FamFS can do so via the PDF slide deck from LPC2025.