From mboxrd@z Thu Jan  1 00:00:00 1970
From: Danny Milosavljevic <dannym@scratchpost.org>
Subject: Re: Kernel modules in initrd
Date: Mon, 26 Feb 2018 17:26:47 +0100
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To: Ludovic =?ISO-8859-1?Q?Court=E8s?= <ludo@gnu.org>
Cc: guix-devel@gnu.org

Hi Ludo,

On Mon, 26 Feb 2018 16:20:08 +0100
ludo@gnu.org (Ludovic Court=C3=A8s) wrote:

> I suppose the bits I=E2=80=99ve promised to detect necessary modules base=
d on
> modules.alias and /sys should be useful here?

Definitely!

I've posted a working patch series (v3, "Load Linux module only when suppor=
ted
hardware is present") of the current kmod-based autoloader to guix-patches.
It's using an old-ish kmod - but otherwise it works fine.

So what we would need next is something like modprobe written in guile.

I think that ./gnu/build/linux-modules.scm load-linux-module* already does =
that.

The only part missing is to replace %modprobe-wrapper by a guile script
which imports ./gnu/build/linux-modules.scm load-linux-module*, interprets
some of the modprobe options and then masquerades as modprobe without invok=
ing
modprobe.

The reason is that the kernel calls us back when it needs a module (for
example when you mount something and it needs a charset converter or someth=
ing).

(the name of the executable invoked is configured via /proc/sys/kernel/modp=
robe)

This can happen quite early in the boot process - and it took me some time
to get the order and also the environment variables right.  We should be ab=
le
to reuse that for the pure Guile modprobe.

After the patch we don't *manually* load any of the modules - and all the
tests work.  I booted my system with it - that also works.

P.S. How come glibc is in the initrd?  Shouldn't guile have statically link=
ed it?
glibc is like 50000 kiB.  In that case saving 800 kiB is not really worth i=
t...