On Sun, Aug 23, 2026 at 12:43:14PM -0400, Gregory Price wrote: > On Sat, Aug 22, 2026 at 10:40:29AM -0700, Darrick J. Wong wrote: > > > > A bigger question I just thought of is sharing cxlmem between files (aka > > reflink). Is that allowed? I could see a theoretical usecase for > > programs A and B wanting to share some cxlmem for communication or > > heartbeats whilst having their own /a and /b files for their private > > memory. Probably you'd just create a /common file to do that and not > > map the same cxlmem page into /a and /b, right? > > > > Anyway, there's "allowed" and "useful". You could technically do it > (maybe not with FAMFS' current guard rails) - but it would be useless > unless Process A and Process B were in the same coherence domain. >
One point of clarification - useless for both processes to write to the same file concurrently, hence the need for a producer-consumer design as John suggests. And even then the software needs to handle coherence and cacheline write ordering (which is also not guaranteed across coherence domains by any current specification I know of). ~Gregory
