[lug] rmmod -a in cron

[D. Stimits]

Nate Duehr wrote:
> 
> So...
> 
> I'm wondering why a kernel RPM upgrade on an older RedHat machine (6.1)
> put a crontab in that does an rmmod -a every so often?
> 
> Is there a "this is the right thing to do" kind of explanation for it?

With the -a option it should remove modules it believes are
autocleanable. How it knows which ones are or are not I don't know, it
seems to have the particular audio module improperly marked.

But the idea is that some modules are available on demand by something
like a kernel daemon or other autoloader. If it was truly autoloadable,
it would only unload when nothing is using it; and if it was unloaded
and something requested it, it would load itself. In between it would
save on memory.

I have always been curious as to how a module is marked as autoloadable,
allowing it to be loaded on demand, since my kernels have all had this
support, but a few modules are annoying enough that it fails. It'd be a
worthy topic of one of the meetings, perhaps a 10 minute thing on "all
about loadable module maintenance".

D. Stimits, stimits at idcomm.com

> 
> It really caused a friend and I some grief on a machine that needed the
> soundcard module available 100% of the time, but where there could be
> gaps in when the application software actually was using the card.
> 
> (Actually the problem is, when you yank out the sound card with rmmod -a
> in a 2.2.17 kernel, it segfaults the mixer application, aumix, never to
> return again... and the default level settings without aumix loaded are
> so low nothing can reasonably be done with them.)
> 
> So there's probably more than one question hiding in here, but any
> enlightenment would be appreciated...
> 
> --
> Nate Duehr <nate at natetech.com>
> 
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