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

[Ed Sweetman]

Witukind wrote:
> On Wed, 10 Dec 2003 20:33:24 +0100
> mru@xxxxxx (Måns Rullgård) wrote:
>
>
> > Witukind <witukind@xxxxxxxxxxxxxxxxxx> writes:
> >
> >
> > > On Tue, 09 Dec 2003 10:39:32 +0100 mru@xxxxxx (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.


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