Re: Linux kernel in-tree Rust support

[Josh Triplett]

On Tue, Jul 28, 2020 at 10:40:38PM +0200, Pavel Machek wrote:
> > We just need to make sure that any kernel CI infrastructure tests that
> > right away, then, so that failures don't get introduced by a patch from
> > someone without a Rust toolchain and not noticed until someone with a
> > Rust toolchain tests it.
> 
> So... I'm fan of Rust, but while trying to use it one thing was obvious: it
> takes _significantly_ longer than C to compile and needs gigabyte a lot of RAM.
> 
> Kernel is quite big project, can CI infrastructure handle additional load?
> 
> Will developers see significantly longer compile times when Rust is widespread?

I wouldn't expect the addition of Rust to the kernel to substantially
impact overall build time; on balance, I'd expect the major bottleneck
in kernel builds to continue to be linking and other serialized steps,
not compiling and other highly parallel steps.

There are also *many* things that can be done to improve Rust build time
in a project. And I don't expect that in-kernel Rust will have many
dependencies on third-party crates (since they'd need to be checked into
the tree).