Re: udev sysfs docs Re: State of devfs in 2.6?

Ed Sweetman
2003-12-10T20:47:10Z

Witukind wrote:
> On Wed, 10 Dec 2003 20:33:24 +0100
> mru@kth.se (Måns Rullgård) wrote:
>
>
>>Witukind <witukind@nsbm.kicks-ass.org> writes:
>>
>>
>>>On Tue, 09 Dec 2003 10:39:32 +0100 mru@kth.se (Måns Rullgård) wrote:
>>>
>>>
>>>>>Is there a specific case for which people want this feature?
>>>>>Offhand it seems like a slightly odd thing to ask for...
>>>>
>>>>I believe the original motivation for module autoloading was to
>>>
>>>save> memory by unloading modules when their devices were unused.
>>>Loading> them automatically on demand made for less trouble for
>>>users, who> didn't have to run modprobe manually to use the sound
>>>card, or> whatever. This could still be a good thing in embedded
>>>systems.>
>>>
the biggest advantage from modules is the ability to enable/disable
devices with different initialization configurations without rebooting,
including the use of devices that aren't present during boot or may be
added to a system that cant be put down to reboot. Embedded systems
usually do not change, that's just part of being embedded, modules dont
really make sense there unless things like filesystems and non-device
modules never get used at the same time and memory is limited such that
100KB actually matters.

>>>I don't see why it wouldn't be a good thing for regular systems
>>>also. Saving memory is usually a good idea.

True, but how about we start being good memory users where it counts the
most, like gui's/userspace land and then worry about the sub 1MB usage
that kernels exist in.

>>The biggest modules are about 100k. Saving 100k of 1 GB doesn't
>>really seem worth any effort.
>
>
> I don't have 1 Gb of memory. On my laptop with 16 mb RAM saving 100k is worth
> the effort.

Then why do you use a sylpheed, which is gtk instead of something in a
terminal that uses much less memory (doesn't require xfree86, which
you're probably also using instead of tinyX) and toolkits, pixmaps etc.
Obviously, 100k is not worth _your_ effort.

I'm not saying module use is more memory efficient than not or vice
versa, but if memory usage in the 100K range is going to be the only
argument for autoloading/unloading of modules then it's really _not_
worth the effort unless someone can give that kind of support without
trying. Your fight for memory efficiency should start where the
inefficiency is the largest, and work it's way down, not the other way
around.