I see that there is some limited support for dax mapping of fuse files, but it seems to be specifically for virtiofs. I admit I barely understand that use case, but there is another fuse/dax use case that I’d like to explore. I would appreciate feedback on this, including pointers to RTFM material, etc. I’m interested in creating a file system interface to fabric-attached shared memory (cxl). Think of a fuse file system that receives metadata (how MD is distributed is orthogonal) and instantiates files that are backed by dax memory (S_DAX files), such that the same ‘data sets’ can be visible as mmap-able files on more than one server. I’d like feedback as to whether this is (or could be) doable via fuse. Here is the main rub though. For this to perform adequately, I don’t think it would be acceptable for each fault to call up to user space to resolve the dax device & offset. So the kernel side of fuse would need to cache a dax extent list for each file to TLB/page-table misses. I would appreciate any questions, pointers or feedback. Thanks, John Groves Micron
