I'm still evaluating the proposal to use memfds but I'm not sure if the issue that David Hildenbrand mentioned about additional memory consumed in pagecache (which has to be addressed) is the only one we will encounter with this approach. If anyone knows of any potential issues with using memfds as named anonymous memory, I would really appreciate your feedback before I go too far in that direction.
[MAP_PRIVATE memfd only behave that way with 4k, not with huge pages, so I think it just has to be fixed. It doesn't make any sense to allocate a page for the pagecache ("populate the file") when accessing via a private mapping that's supposed to leave the file untouched]
My gut feeling is if you really need a string as identifier, then try going with memfds. Yes, we might hit some road blocks to be sorted out, but it just logically makes sense to me: Files have names. These names exist before mapping and after mapping. They "name" the content.
Maybe it's just me, but the whole interface, setting the name via a prctl after the mapping was already instantiated doesn't really spark joy at my end. That's not a strong pushback, but if we can avoid it using something that's already there, that would be very much preferred.
-- Thanks, David / dhildenb
