Re: [PATCH] Remove module reference counting.

From: Rusty Russell (rusty@rustcorp.com.au)
Date: Fri Jul 25 2003 - 17:26:11 EST


In message <20030725122651.4aedc768.shemminger@osdl.org> you write:
> On Fri, 25 Jul 2003 04:00:18 +1000
> Rusty Russell <rusty@rustcorp.com.au> wrote:
> > If module removal is to be a rare and unusual event, it
> > doesn't seem so sensible to go to great lengths in the code to handle
> > just that case. In fact, it's easier to leave the module memory in
> > place, and not have the concept of parts of the kernel text (and some
> > types of kernel data) vanishing.
> >
> > Polite feedback welcome,
> > Rusty.
> > --
>
> There are two possible objections to this:
> * Some developers keep the same kernel running and load/unload then reload
> a new driver when debugging. This would break probably or at least cause
> a large amount of kernel growth. Not that big an issue for me personally
> but driver writers seem to get hit with all the changes.

No, it would just leak memory. Not really a concern for developers.
It's fairly trivial to hack up a backdoor "remove all freed modules
and be damned" thing for developers if there's real demand.

> * Drivers might get sloppy about not cleaning up timers and data
> structures -- more than they are already. You might want to have a
> kernel debug option that overwrite's the unloaded text with
> something guaranteed to cause an oops.

I already have a poisoning patch for init code, when some modules
seemed to suffer from this being discarded. I can extend it.

Thanks!
Rusty.

--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
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