Date: Fri, 09 Jul 2004 16:36:05 +0200 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: Robert Watson <rwatson@freebsd.org> Cc: arch@freebsd.org Subject: Re: [RFC] kldunload -f argument. Message-ID: <23761.1089383765@critter.freebsd.dk> In-Reply-To: Your message of "Fri, 09 Jul 2004 10:32:15 EDT." <Pine.NEB.3.96L.1040709102423.60816K-100000@fledge.watson.org>
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In message <Pine.NEB.3.96L.1040709102423.60816K-100000@fledge.watson.org>, Robert Watson writes: > >On Fri, 9 Jul 2004, Brian Somers wrote: > >> > I'm not sure I see any real-world application for this ? Can you give an >> > example ? Why would you load a module and not use it ? >> >> I can't think of any non-development-environment reasons unless there's >> room for modules being loaded early to be able to make assumptions about >> their environment at ACTIVATE time (such as a root filesystem being >> available). > >We actually have an example in the form of snd_driver, which forces all >the sound modules to load, with the intent that when you unload, the >attached ones are left running. We also have a lot of functionality >compiled into GENERIC that many people don't use or use only infrequently >-- when that functionality is compiled into modules, we frequently >automatically load modules during a file system mount, netgraph pieces, >etc. When they're no longer in use, they hang around. In a world where >we consistently load modules on demand, and those modules remain idle >after use, it would be somewhat nice to be able to simply say "Ok, modules >no longer needed, please unload yourselves". Yes, but I found out why this is troublesome: Modules != KLD. One KLD may contain multiple modules. I think that if we need activate/quiesce on a per module interface then we should not do it with KLD granularity. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
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