rc.conf(5): comparing kld_list and kldload

[Polytropon]

On Mon, 22 Oct 2018 05:26:18 +0100, Graham Perrin wrote:
> From <https://www.freebsd.org/cgi/man.cgi?query=rc.conf&sektion=5&manpath=FreeBSD>: 
> 
> > …
> > 
> > kld_list    (str) A list of kernel modules to load right after 
> >             the local disks are mounted.  Loading modules at 
> >             this point in the boot process is much faster than 
> >             doing it via /boot/loader.conf for those modules 
> >             not necessary for mounting local disk.
> > …
> 
> Is there ever any benefit to using kldload instead of kld_list?

It is important when you consider the _time_ during system
startup. Sometimes modules require to be loaded at a certain
time, that's when you can (or cannot) use kld_list, which is
the _default_ method of loading kernel modules.

early: via /boot/loader.conf

intermediate: via kld_list in /etc/rc.conf

almost final: via kldload calls in /etc/rc.local

It's also possible for scripts in /usr/local/etc/rc.d/ to
load kernel modules, and you could even add something to
/etc/rc itself to achieve "really final" loading (even though
manual additions to /etc/rc are discouraged for good reasons).



> Background: difficulty with radeonkms and sddm following a switch
> of -CURRENT to stable/12
> 
> <https://lists.freebsd.org/pipermail/freebsd-current/2018-October/071783.html>
> 
> I'm toying with the possibility that faster is not always best;
> that a specific load/start order might help. 

Yes, this is such a case.



-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...