The Rust compiler is very slow and has very high memory requirements. Compiling the Kernel on e.g. older Raspberry Pis is already barely possible and will potentially become completely impossible once rust enters the kernel.
There are many MCUs that run Linux but definitely are incapable of compiling it.
IIRC most of the build time of a rust program is spent not in the rust compilation proper but in LLVM doing code generation and optimization. I hope both LLVM will become more efficient with time, and rust will learn to pass it such IR that it can process faster. There are obvious incentives for both of these things.
But of course it would be sad if the minimum requirements to compile the kernel grew again, and now excluded older RPis.
gcc and clang are pretty slow on the scale of all programming languages. Rust is basically the only thing that modern C/C++ compilers are faster than. Should we abandon C and C++ for something else then?
There are many MCUs that run Linux but definitely are incapable of compiling it.
IIRC most of the build time of a rust program is spent not in the rust compilation proper but in LLVM doing code generation and optimization. I hope both LLVM will become more efficient with time, and rust will learn to pass it such IR that it can process faster. There are obvious incentives for both of these things.
But of course it would be sad if the minimum requirements to compile the kernel grew again, and now excluded older RPis.