Linux kernel optimization: the role of C and the rise of Rust

The debate regarding whether modern programming languages can replace C in the Linux kernel continues to evolve. Linus Torvalds has previously noted that Linux's speed is not merely a result of being written in C, but rather the result of decades of optimization around a language that allows developers to closely control compiler-generated code and assembly.

Key performance factors in the kernel include system calls, memory management, schedulers, and file systems. For these critical paths, even minor instruction efficiencies or optimized memory access can significantly impact overall performance. For example, the kernel uses mechanisms like dcache and RCU-walk to accelerate file name resolution and reduce synchronization costs.

While C remains the primary foundation of the kernel, Linux has begun integrating Rust. This move aims to combine native performance and low-level control with enhanced memory safety guarantees. Developers such as Greg Kroah-Hartman have advocated for the inclusion of Rust, highlighting a growing need for Rust developers within the ecosystem.