Linux 7.3 Makes Preparations Toward Upstreaming FAMFS File-System
The Linux 7.3 cycle has seen the merge of NVDIMM and direct access (DAX) patches, with most of the DAX/NVDIMM activity focused on preparing for the upcoming submission of Micron's FAMFS file-system.
Intelligence analysis by Llama
The DAX code with Linux 7.3 has seen a number of fixes, code refactoring, and other improvements in preparing for the FAMFS introduction. Micron is hoping to see FAMFS upstreamed in 2026.
Linux 7.3 is getting ready to support a new file system called FAMFS. This file system is special because it's designed to work with very large amounts of memory, like the kind used in supercomputers. It's not for regular computers, but for really powerful machines that need to handle a lot of data.
Analysis
FAMFS and Linux 7.3 Preparations
The Linux 7.3 cycle has seen the merge of NVDIMM and direct access (DAX) patches, with most of the DAX/NVDIMM activity focused on preparing for the upcoming submission of Micron's FAMFS file-system. The DAX code with Linux 7.3 has seen a number of fixes, code refactoring, and other improvements in preparing for the FAMFS introduction.
Micron is hoping to see FAMFS upstreamed in 2026 and the patches for the file-system itself have now undergone thirteen rounds of patch review. This fabric-attached memory file system is going to be quite important for modern CXL servers moving forward.
FAMFS is not for any general purpose file-system use but is designed around file-based, byte-level access to very large shared/disaggregated memory applications, in the scope of around 100TB+ memory being common. While there has been concerns over the proliferation of file-systems within the Linux kernel, FAMFS is designed specifically for this use.
Micron engineers did experiment with porting to FUSE in user-space but ultimately have found a standalone file-system kernel driver is the best approach. Micron has also committed to maintaining FAMFS with having a clear customer need for it.
FAMFS and Its Importance
FAMFS is designed for fabric-attached memory (FAM) devices and is going to be quite important for modern CXL servers moving forward. The file-system is designed around file-based, byte-level access to very large shared/disaggregated memory applications, in the scope of around 100TB+ memory being common.
FAMFS and Linux
The FAMFS file-system is not for any general purpose file-system use but is designed specifically for this use. Micron engineers did experiment with porting to FUSE in user-space but ultimately have found a standalone file-system kernel driver is the best approach.
Conclusion
The Linux 7.3 cycle has seen the merge of NVDIMM and direct access (DAX) patches, with most of the DAX/NVDIMM activity focused on preparing for the upcoming submission of Micron's FAMFS file-system. The FAMFS file-system is designed for fabric-attached memory (FAM) devices and is going to be quite important for modern CXL servers moving forward.
Key points
- The Linux 7.3 cycle has seen the merge of NVDIMM and direct access (DAX) patches.
- Most of the DAX/NVDIMM activity is focused on preparing for the upcoming submission of Micron's FAMFS file-system.
- FAMFS is designed for fabric-attached memory (FAM) devices and is going to be quite important for modern CXL servers moving forward.
- FAMFS is not for any general purpose file-system use but is designed around file-based, byte-level access to very large shared/disaggregated memory applications.
- Micron engineers did experiment with porting to FUSE in user-space but ultimately have found a standalone file-system kernel driver is the best approach.
If FAMFS is successfully upstreamed, it could lead to significant improvements in the performance and efficiency of modern CXL servers. This could have a positive impact on the development of new technologies and applications that rely on these servers.
However, the upstreaming of FAMFS is not without its challenges. The file system is still in the experimental phase, and there may be issues with its compatibility and stability. Additionally, the adoption of FAMFS could be slowed down by the need for significant changes to existing systems and infrastructure.