October 8, 2026 – At the Linux Plumbers Conference 2026 held recently in the Czech Republic, Huawei engineers formally presented an experimental file system called XMFS.
XMFS, short for eXpress Memory File System, is a specialized file system designed for modern Linux servers equipped with CXL 3.0 or Huawei’s Unified Bus. Both CXL 3.0 and Huawei’s Unified Bus are memory-semantic interconnect technologies that allow remote memory to be addressed directly as if it were local memory. The core design goal of XMFS is to enable direct access to cross-node shared memory through standard POSIX file system interfaces, so that upper-layer applications can use it without modification.
Compared with other vendors’ CXL-oriented file system proposals such as FAMFS and DAXFS, XMFS’s main advantage is its native support for conventional POSIX file operations. In basic performance benchmarks disclosed at LPC 2026, XMFS showed notable improvements over the traditional tmpfs file system.
In terms of application scenarios, Huawei has already tested and verified XMFS in use cases such as multi-node container image sharing and metadata-intensive workloads. This suggests that XMFS could be practically useful in containerized deployments and in AI and high-performance computing workloads that require frequent metadata access.
At present, XMFS remains in an experimental stage and has not yet been submitted to the Linux kernel mailing list for community review. Huawei engineers also noted several open challenges, including cross-node metadata synchronization, software cache consistency in the absence of hardware cache coherence, unification of different memory-semantic interconnects and RDMA transports, and cross-node memory capacity management and tiering.
