[SOLVED]Kernel loads all modules.

weelkin · n00b Joined: 13 Dec 2011 Posts: 7

Hi there,

i just started installing gentoo and discovered something strange (at least for me as a gentoo newbee). I used genkernel to build my kernel. I managed to set up an encrypted root, but now when booting up, a huge amount of kernel modules is loaded. Most of them are not needed. In total there are 177 modules loaded. Is this behaviour normal? Afaik the kernel should probe for the hardware and just load modules for which it finds hardware.

Thanks in advance,

weelkin

ultraincognito · Guru Joined: 03 Jun 2011 Posts: 346 Location: Ukraine

If all works good then there isn't nothing bad. Modules aren't very weighty for RAM.
But you really going to to understand and to improve your Gentoo system then do next:
Firstly, look at /usr/share/genkernel/YOUR_ARCH/modules_load.
Secondly, if do want more. Learning configure the kernel! On begin you can switch on the many options in the kernel. It gives more chance that the kernel would load fine. And gradually exclude the excess modules.

weelkin · n00b Joined: 13 Dec 2011 Posts: 7

Thanks for the answer,

will the initram kernel load all the modules listed in this file? Regardless of there is hardware for this modules or not? How does it work then with other distributions like .e.g Arch linux? In my arch installation only the needed modules are loaded, although i haven't touched the kernel.

Thanks in advance,

weelkin

krinn · Watchman Joined: 02 May 2003 Posts: 7470

Yes, it's bad that a module is load when not need, you're wasting ressource.
I'm not familiar with genkernel, but if i need to build the most generic kernel i could, then i would built everything as module, but certainly not load all of them thru autoload !

Check the file ultraincognito spoke about, and clean that file from the mess if genkernel put every module in it into the initram.

And for others distributions, and for gentoo too, you don't have to load all modules in initram to make a kernel working, only the ones that are need to boot, mostly hdd controller drivers, next to that, leaving udev do the work for the hardware that remain so you'll only have module that will be in fact real use.

Still without knowing if genkernel do that (load all modules in the initram file), gentoo is about choices, and you have to do yours, but sometimes a dev make one for you, if you don't agree with it, change it.
Even that choice seem a bit rude at first, it could be seen as a good default choice to do, as it will make sure it will boot, at a prize of a bloat system.
I think genkernel is there for people that never really handle a kernel, and genkernel is trying its best to make a valid bootable kernel, and not a top optimize kernel.

Look at the excellent linux sea for more help with kernel and module : http://swift.siphos.be/linux_sea/

ultraincognito · Guru Joined: 03 Jun 2011 Posts: 346 Location: Ukraine

NeddySeagoon · Posted: Wed Dec 14, 2011 8:03 pm Post subject:

weelkin,

Roll your own kernel starting with one of Pappys Seeds
Post problems in Pappys support thread.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

weelkin · n00b Joined: 13 Dec 2011 Posts: 7

Thanks for all the answers,

i found the answer in the arch-linux wiki

https://wiki.archlinux.org/index.php/Mkinitcpio#Overview

Arch is including udev in the initramfs to avoid loading unecessary modules. I will look into "dracut" to build a similiar initramfs with udev as a failsave and a initramfs
with just the modules included which my laptop needs.
I'll do the same with my kernel, just in case i have to change the hardware of my system.

Regards,

weelkin

cach0rr0 · Posted: Wed Dec 14, 2011 10:40 pm Post subject:

weelkin · n00b Joined: 13 Dec 2011 Posts: 7

Thanks for the link this howto is awsome

I learned alot.
If i don't want to built some modules into the kernel, i'd have to copy the module files into the initramfs and them manully insmod them, right?

Regards,

welkin

cach0rr0 · Posted: Thu Dec 15, 2011 1:03 am Post subject:

MACHINE · Posted: Sat Dec 17, 2011 1:37 am Post subject:

i got the same issue. i made a minimalist-style kernel/modules, but when system rebooted, i found a lot of unneeded modules loaded. i don't want to try auto-probe stuffs either, but want thing KISS - just my specified modules. any hints?
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Hi, Gentoo men!!

NeddySeagoon · Posted: Sat Dec 17, 2011 1:15 pm Post subject:

MACHINE,

If you want lean and mean you need to understand what the modules do and why you would want them or not.
That means don't start with genkernel. You can use genkernel to do the build and install if doing it yourself makes you nervous but you must configure the kernel yourself.

There are a few rules of thumb to help:-

MACHINE · Posted: Sun Dec 18, 2011 1:00 am Post subject:

i understood and i was following the rules of thumb. the issue is, as i said, genkernel disregarded my kernel configuration, and built modules i never need. anyway, thx for your suggestion.
_________________
Hi, Gentoo men!!

NeddySeagoon · Posted: Sun Dec 18, 2011 7:50 pm Post subject:

MACHINE,

You can tell genkernel yo use your .config file rather than its defualt one. Try genkernel --help or man genkernel for the exact incatation.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.