nix: fix jemalloc on 16k pages

[alexandru0-dev]

update fenix input flake and add rust-jemalloc-sys to buildInputs to support 16k pages (like on asahi linux)

[saghen]

Would it make sense to only include rust-jemalloc-sys on systems that require it, maybe by checking getconf PAGESIZE?

[alexandru0-dev]

Would it make sense to only include rust-jemalloc-sys on systems that require it, maybe by checking getconf PAGESIZE?

Idk tbh, I was basing myself from patches sent to nixpkgs upstream and how they deal with it

I'm happy to experiment tho

[saghen]

Yeah, that'd be great! rust-jemalloc-sys is 46MiBs so it'd be nice to avoid it when we don't need it

~> nix-build -A rust-jemalloc-sys '<nixpkgs>'
~> nix path-info -Sh ./result
/nix/store/kxknc3j9nc03via3gafi4a3kanraa723-jemalloc-5.3.0	 46.0 MiB

[alexandru0-dev]

maybe by checking getconf PAGESIZE?

You can't really do that it in packages

Maybe a flag that can enable it and so you have 2 builds?

Or you could check if the platform is aarch64 and only include it on that as it seems the only platform where pages can be different from 4k

[saghen]

Yeah, looks like there's some work on implementing it: NixOS/nix#12446

Checking if the system is aarch64 works for me for now. I'll revisit this when support has been added upstream for checking the page size

[alexandru0-dev]

Yeah, looks like there's some work on implementing it: NixOS/nix#12446

Yeah support in needed in the nix core, so until then...

Checking if the system is aarch64 works for me for now.

Perfect, I will update the PR then

I'll revisit this when support has been added upstream for checking the page size

I will look into the PR later, but it seems to me like it's something that needs also to be dealt even for older versions of nix

[saghen]

Thanks!