Rust-for-Linux VS flume

Rust is backwards compatible when you stick to stable features, but the kernel uses unstable features that can and do incur breaking changes.

https://github.com/Rust-for-Linux/linux/issues/2

> How would this work?

Don't know exactly what you're asking.

> And why would it be a better idea?

Poorly written device drivers are a significant attack vector. It's one of the reasons Linux is now exploring using Rust for its own device drivers.[0] You may be asking -- why Rust and not some other language? Rust has many of the performance and interoperability advantages of C and C++, but as noted, makes certain classes of memory safety issues impossible. Rust also has significant mindshare among systems programming communities.

[0]: https://rust-for-linux.com

Ctrl-F "rust"

https://rust-for-linux.com/ links to LWN articles at https://lwn.net/Kernel/Index/#Development_tools-Rust that suggest that only basic modules are yet possible with the rust support in Linux kernels 6.2 and 6.3.

Rust-for-linux links to the Android binder module though:

> Android Binder Driver: This project is an effort to rewrite Android's Binder kernel driver in Rust.

> Motivation: Binder is one of the most security and performance critical components of Android. Android isolates apps from each other and the system by assigning each app a unique user ID (UID). This is called "application sandboxing", and is a fundamental tenet of the Android Platform Security Model.

> The majority of inter-process communication (IPC) on Android goes through Binder. Thus, memory unsafety vulnerabilities are especially critical when they happen in the Binder driver

... "Rust in the Linux kernel" (2021) https://security.googleblog.com/2021/04/rust-in-linux-kernel... :

> [...] We also need designs that allow code in the two languages to interact with each other: we're particularly interested in safe, zero-cost abstractions that allow Rust code to use kernel functionality written in C, and how to implement functionality in idiomatic Rust that can be called seamlessly from the C portions of the kernel.

> Since Rust is a new language for the kernel, we also have the opportunity to enforce best practices in terms of documentation and uniformity. For example, we have specific machine-checked requirements around the usage of unsafe code: for every unsafe function, the developer must document the requirements that need to be satisfied by callers to ensure that its usage is safe; additionally, for every call to unsafe functions (or usage of unsafe constructs like dereferencing a raw pointer), the developer must document the justification for why it is safe to do so.

> We'll now show how such a driver would be implemented in Rust, contrasting it with a C implementation. [...]

This guide with unsafe rust that calls into the C, and then with next gen much safer rust right next to it would be a helpful resource too.

What of the post-docker container support (with userspaces also written in go) should be cloned to rust first?

Rust-for-Linux issue tracker

Yes, I definitely agree that it's a problem that pr_info implicitly wraps its arguments in unsafe {}. I wrote my own Pull Request with a trival fix.

Note that this template won't work with Linux 6.1, which has very minimal Rust support. You'll want the RustForLinux tree, or maybe Linux 6.2.

You can join Rust for Linux zulip chat by requesting invite using the link in https://github.com/Rust-for-Linux/linux 's README.

The repository seems abandoned; or maybe complete?

At work we use flume, which is another capable multi-producer, multi-consumer async-capable channel [1]. It's great for shuffling data between threads, as well as between async tasks, and between threads and async tasks. Basically any time you want to pieces of code to exchange data or signals without pesky shared state.

1: https://github.com/zesterer/flume

I also like flume, it has impressive performance (although not the best). More importantly, it's written only with safe rust. https://github.com/zesterer/flume

The most commonly suggested replacement for mspc is crossbeam-channel; flume is also relatively popular.

It's not officially deprecated, but the alternatives on crates.io are considered better. flume and crossbeam-channel feature less unsafe code and offer better performance. Benchmarks.

it's slow (checkout flume's benchmarks for example)

I would have done the same. I think, and I might be wrong, but the only other alternative, besides anything unsafe, would be to pass mutex back, but I am not sure this would be faster. Btw, I have not done testing, but you might want to look at Flume for your mpsc channels: https://github.com/zesterer/flume Flume, seems to be very fast mpsc implementation. I am planning to evaluate it for logging system.

For concurrency/parallelism, you launch at most 2 * CPU Cores, PIN them and use a fast broker to spread the task (like a ring buffer or an MPSC). But you keep linear scan, tight loops, SIMD friendly data, on each. You are not switching context that much, and instead, bet you will process the batch fast. (CPUs are fast today!)

https://crates.io/crates/flume and https://crates.io/crates/crossbeam-channel provide MPMC channels.