Re: How to load ffs module via boot.cfg?

[Jukka Ruohonen <jruohonen%iki.fi@localhost>]

On Mon, Jun 01, 2020 at 05:26:16AM -0700, Paul Goyette wrote:
> You can strip out a lot more modules and still have a functioning
> system.  Mostly you can remove all the device drivers for devices
> that don't exist, but there are other things, too.

Another small module question: when running a -current kernel with 9.0
userland, the compat_90 module is loaded, as I believe it should given the
MODULAR_DEFAULT_AUTOLOAD option. Due to module_start_unload_thread(9), it is
also over and over again unloaded:

$ modstat > d && sleep 3 && modstat > dd && diff -u d dd
--- d   2020-06-02 08:19:44.893168878 +0300
+++ dd  2020-06-02 08:19:47.915516801 +0300
@@ -26,6 +26,7 @@
 cir               driver   builtin  -        1       - ir
 clockctl          driver   builtin  -        0       - -
 coda              vfs      builtin  -        0       - vcoda
+compat_90         exec     filesys  a        0       - -
 compat_util       misc     builtin  -        0       - -
 coredump          misc     builtin  -        0       - -
 coretemp          driver   boot     -        0       - sysmon_envsys

This kind of constant unload/load trashing does not seem optimal. I would
expect there to be also a performance impact.

So can I control module unloading at runtime? That is, I want:

$ sysctl kern.module.autoload
kern.module.autoload = 1

But there is no "kern.module.autounload", which I would want to be 0.

- Jukka