Linus Torvalds Speaks on the the divide between Rust and C Linux developers an the future Linux. Will things like fragmentation among the open source community hurt the Linux Kernel? We’ll listen to the Creator of Linux.
For the full key note, checkout: Keynote: Linus Torvalds in Conversation with Dirk Hohndel
You must log in or register to comment.
If you believe in ADTs, limiting mutation, & a type system that goes beyond Rust’s affine types + lack of refinements (including a interleaved proof system), you could be writing kernel code in ATS which compiles to C.
I took notes for the benefit of anyone who doesn’t like their info in video form. My attempt to summarize what Linus says:
He enjoys the arguments, it’s nice that Rust has livened up the discussion. It shows that people care.
It’s more contentious than it should be sometimes with religious overtones reminiscent of vi versus emacs. Some like it, some don’t, and that’s okay.
Too early to see if Rust in the kernel ultimately fails or succeeds, that will take time, but he’s optimistic about it.
The kernel is not normal C. They use tools that enforce rules that are not part of the language, including memory safety infrastructure. This has been incrementally added over a long time, which is what allowed people to do it without the kind of outcry that the Rust efforts produce by trying to change things more quickly.
There aren’t many languages that can deal with system issues, so unless you want to use assembler it’s going to be C, C-like, or Rust. So probably there will be some systems other than Linux that do use Rust.
If you make your own he’s looking forward to seeing it.
Thank you for the write-up!!
Good human.
vi versus emacs
You write “vi versus the world” funny.
I took notes for the benefit of anyone who doesn’t like their info in video form.
I love you.
So probably there will be some systems other than Linux that do use Rust.
Isn’t there Redox OS?
Edit: yes, it’s still alive and kicking.
Doing the lord’s work, thank you.
On a tangential note, what does Linus used, Vi or Emacs?
He uses a version of Emacs called MicroEmacs.
I recall seeing his MicroEmacs configuration a while back when I was exploring options to start using Emacs.
MicroEmacs
In testing, to settle a bet by a rabid cult-of-vi peer, I opened a given set of files in each editor, each a day apart because I couldn’t be arsed to clear caches. This guy, otherwise a prince, was railing about emacs, but otherwise suffered days of waiting.
10/10 the memory usage by his precious vi was same-or-more than emacs.
There’s so many shared libs pulled in by the shell that all the fuddy doomsaying about bloat is now just noise.
I avoid vi because even in 1992 it was crusty and wrong-headed. 30 years on the hard-headed cult and the app haven’t changed.
I don’t see how microEmacs can improve on what we have by default, and I worry that the more niche the product is the harder it will be to find answers online. But I’m willing to be swayed if anyone can pitch its virtues.
MicroEmacs was written in 1985 and has nothing to do with GNU Emacs (which people just call Emacs these days). It’s entirely outside of the vi-vs-emacs war.
Yeah the interface for it - and functionality - is more like nano than actual Emacs.
my money is on vi or vi derivates.
This is a great summary. Thanks!
C, C-like, or Rust
As always, Ada gets no respect.
Have you actually ever used Ada? It’s like programming with handcuffs on.
Nor does Forth (which used to be a common choice for “first thing to bootstrap on this new chip architecture we have no real OS for yet”). Alas, they’re just not popular languages these days.
Start the linuxa or alinux project and off you trot. Find a better name than I did here and you’ll be fine.
Adux
Anixa for the win
Ladux? Linda? +Linux, pronounced “Add a Linux” -> Ada Linux? LinLace?
Lada
Images of smoking Eastern European jalopy intensifies.
Thank you for the summary!
So probably there will be some systems other than Linux that do use Rust
There’s one called Redox that is entirely written in Rust. Still in fairly early stages, though. https://www.redox-os.org/
If you make your own he’s looking forward to seeing it.
Not a programmer whatsoever but I’ve heard about Zig and people comparing it to Rust, what’s the deal with it?
Zig is indeed designed specifically for such tasks as system programming and interoperability with C code. However it is not yet ready for production usage as necessary infrastructure is not yet done and each new version introduces breaking changes. Developers recomend waiting version 1.0 before using it in any serious project.
Zig is “c”, but modern and safe.
The big selling points compared to Rust are:
- A better syntax
- No hidden control flow
- No hidden memory allocation
- Really great interop with C (it’s almost as if you just include the C code as you would in a C code base…)
- Fast compile time
- it’s more readable
- it’s simpler to learn
The syntax is really close to the C language; any C programmer can pick up Zig really fast.
IMO Zig is a far better choice to go in the kernel than Rust.
Linux has tried to include CPP in it, and it failed.
So imagine if trying to fit in a C-like cousin failed, how far they are to fit an alien language like Rust…
For more information: https://ziglang.org/learn/why_zig_rust_d_cpp/
Zig is a very new and immature language. It won’t be kernel-ready for at l’East another 10 years.
a better syntax
That’s pretty suggestive. Rust syntax is pretty good. Postfix
tryis just better for example.Zig also uses special syntax for things like error and nullability instead of having them just be enums, making the language more complex and less flexible for no benefit.
Syntax is also not everything. Rust has extremely good error messages. Going through Zig’s learning documentation, half the error messages are unreadable because I have to scroll to see the actual error and data because it’s on the same line as the absolute path as the file were the error comes from
No hidden memory allocation
That’s a library design question, not a language question. Rust for Linux uses its own data collections that don’t perform hidden memory allocations instead of the ones from the standard library.
it’s more readable
I don’t know, Rust is one of the most readablelangueage for me.
Fast compile time
Is it still the case once you have a very large project and make use of comptime?
it’s simpler to learn
Not true. Because it doesn’t have the guardrails that rust has, you must build a mental model of where the guardrails should be so you don’t make mistakes. Arguably this is something that C maintainers already know how to do, but it’s also not something they do flawlessly from just looking at the bugs that regularly need to be fixed.
Being able to write code faster does not equate being able to write correct code faster.
Really great interop with C
Yes, because it’s basically C with some syntax sugar. Rust is a Generational change.
Zig is “c”, but modern and safe.
Zig is safer than C, but not on a level that is comparable to Rust, so it lacks its biggest selling point. Unfortunately just being a more modern language is not enough to sell it.
So imagine if trying to fit in a C-like cousin failed
C++ was not added to Linux because Linus Torvalds thought it was an horrible language, not because it was not possible to integrate in the kernel.
Zig has other selling points, that are arguably more suitable for system programming. Rust’s obsession with safety (which is still not absolute even in rust) is not the only thing to consider.
It is absolue in safe Rust, aka 99% of Rust code.
UB is only one class of error though. I get nervous when people talk about re-writing battle hardened code which has been used - and reviewed by the community - for decades because there are going to be many subtleties and edge cases which are not immediately apparent for any developer attempting a re-implementation.
Linux has tried to include CPP in it, and it failed.
So imagine if trying to fit in a C-like cousin failed, how far they are to fit an alien language like Rust…
But that wasn’t about the syntax, but about the fastnesses, size and control, want it? Things that shouldn’t be much of an issue to Rust.
Zig is feasible for systems programming and some, (most notably, the Primeagen in one video) claim it should have gone into the kernel instead of Rust, but I don’t know Zig so I don’t feel qualified to comment beyond that.
How is it that no matter what the damn topic is, Linux always seems to be the most level-headed in the room? I really admire him for that…
Linus did have emotion control issues and was not always completely rational, but he’s gone a long way towards being incredibly responsible to his child that powers the world.
Also, he long understands that Linux ain’t a hobby project, which some programmers still get to think.
Good bot!
I don’t want to watch a video about it.
I’d like to know it, but a couple of sentences wouldn’t have hurt
I also dont like videos for this stuff. Summarized using kagi’s universal summarizer, sharing here:
- The integration of Rust into the Linux kernel has been a contentious topic, with some long-term maintainers resisting the changes required for memory-safe Rust code.
- The debate over Rust vs. C in the Linux kernel has taken on “almost religious overtones” in certain areas, reflecting the differing design philosophies and expectations.
- Linus Torvalds sees the Rust discussion as a positive thing, as it has “livened up some of the discussions” and shows how much people care about the kernel.
- Not everyone in the kernel community understands everything about the kernel, and specialization is common - some focus on drivers, others on architectures, filesystems, etc. The same is true for Rust and C.
- Linus does not think the Rust integration is a failure, as it’s still early, and even if it were, that’s how the community learns and improves.
- The challenge is that Rust’s memory-safe architecture requires changes to the existing infrastructure, which some long-time maintainers, like the DRM subsystem people, are resistant to.
- The Linux kernel has developed a lot of its own memory safety infrastructure over time for C, which has allowed incremental changes, whereas the Rust changes are more “in your face.”
- Despite the struggles with Rust integration, Linus believes Linux is so widely used and entrenched that alternative “bottom-up grown-up from the start Rust kernels” are unlikely to displace it.
- Linus sees the embedded/IoT space as an area where alternative kernels built around different languages like Rust may emerge, but does not see Linux losing its dominance as a general-purpose OS.
- Overall, Linus views the Rust debate as a positive sign of the community’s passion and an opportunity to learn, even if the integration process is challenging.
FWIW, it’s a 9 min video and doesn’t contain anything earth shattering or easily summarized. Basically there is some friction between C and Rust devs, and Linus doesn’t think that it’s such a bad thing (there has be interesting discussion) and it’s way too early to call Rust in the kernel a failure.
Thx!
This summary seemed pretty good though.
Rust is harder to write but infinitely safer, and equivalent in speed.
It’s harder to write because it forces you to be careful.
C is easier to get a program to compile. Rust is easier to get a program working correctly.
And because it looks like C, JavaScript, Bash and a few others all mixed up together.
I’ve heard Rust described as “Rust is what you get when you put all the good features of other programming languages together. You can’t read it, but it’s freaking fast!”
It forces you to be careful in the way it wants you to be careful. Which is fine, but it makes it a strange beastie for anyone not used to it.
Yes
But the trade off is well worth it.
It can be, sure. I prefer garbage collectors but I’m not doing systems programming.
I feel like a garbage collector would be too much a performance hit for kernel stuff.
2 things:
-
It’s more the determinacy, a GC randomly fires up and your systems stops for some long amount of time. There are pauseless GCs but that’s a different nightmare.
-
The kernel has things similar to GCs. They’re used for more specialized tasks, and some (like rcu) are absolute nightmares that have take decades to get working.
-
For who?
You
it’s more “it forces you to make it burrow checker friendly”.
A burrow checker is not the only mechanism to write safe code. All the mess of Rust is all because this is the strategy they adopted.
And this strategy, like everything in this world, has trade offs. It just happens that there are a lot, like, - a lot -, of trade offs, and those are insufferable when it comes to Rust…
Borrow* checker, btw
Gotta watch out for those rabbits messing with your kernel
YouTube has a transcribe feature you could use. Or you could keep scrolling if this content isn’t relevant to you.
