On Tue, Apr 11, 2023 at 10:26 PM Willy Tarreau <w@xxxxxx> wrote: > > I don't know, maybe that would be a bit too fine. But at least a tainted > flag is much less intrusive than forcing a user to rebuild and disable > possibly important features that they would only be willing to disable > for just a test. It may be useful early on to have an easy way to check if any Rust modules got loaded (though note that `RUST` is not tristate so far, so you would still have something loaded). It could be extra optional output in e.g. `lsmod`. However, I don't know why that should imply tainting, especially medium- and long-term -- please see below. > have a hard time understanding that code that interacts with their > subsystems, even if they try hard. It's exactly the same reason why > 25 years ago Linus asked to stop abusing assembly code. If a language > is only understood by a subset of developers, by nature it becomes > more difficult to maintain in some areas. Yeah, but that is why the idea was that Rust goes first into subsystems where maintainers are willing to put some time into it now and evaluate its merits. That way we also build more Rust expertise across the kernel over time, so that later it is easier for others (e.g. by having examples of API design and drivers, more people to refer to, better tooling...). But, yes, if Rust grows to be really successful within the kernel, then at some point some basic understanding of Rust will be needed by most kernel developers. I think that is fine, as long as there is enough time to adjust. > Sure, but as you said, "if they can". I thought that it could be both > elegant, lightweight and convenient. But I'm not trying to sell this > idea, just sharing it. To be clear, it is still up to each subsystem to decide whether to take Rust code. What I meant by "if they can" is that, if they are willing to, then ideally the code would go through their tree too. The exception are core APIs, where I asked for flexibility from all sides, so that those subsystems willing to try Rust do not get completely blocked. Cheers, Miguel
