Yeah good point. I don't want write stalls because of subscription requests. For things like filesystem watching (for compilers), it'd be enough to have a form

Yeah good point. I don't want write stalls because of subscription requests. For things like filesystem watching (for compilers), it'd be enough to have a form of snapshot checkpointing. (There were these FS events within 10ms [..]) / (Then the file contents was XXX) / ... (Then there were these FS events) / and so on. Its possible you'd end up in situations where the OS would need to retain old file contents if there's both a pending read from a subscriber and subsequent writes. But in most cases, this is fine. Going back to my original comment, this is the sort of reason I'd like to try this in my own OS kernel rather than try and solve all these problems immediately in linux. It'll give me a chance to try out a few different solutions and see if I can find something that works well.