Kernel configuration options
david at lang.hm
david at lang.hm
Thu Jan 3 12:59:32 EST 2008
one good reason to avoid modules where we cn is that each module that gets
loaded wastes a partial page of memory (arguably ~2k/module on average),
on a system with only 256M ram this can add up to be a noticable amount of
memory lost if you go the route some advocate and make everything a
and given that there is only 1G of 'disk' available to the system to store
modules, I would argue that trying to provide modules for all sorts of
esoteric hardware (USB video was mentioned) is a waste of resources.
make the other modules available for download and installation as needed,
but don't eat up the space otherwise
modules are useful for when you have hardware that's used very
infrequently and the driver is fairly large, but I don't think that there
are many cases where this is a good argument.
I've always built my kernels as monolithic as possible, even for my
laptops, so I know that it can be done (except a few drivers that need to
load firmware). while there are some (vocal) kernel developers who feel
that the kernel shouldn't even understand disk partitioning, and that
everything should be a module, there are many others who feel that the
kernel should not require external assistance for simple situations.
Linus has commented that he also builds his kernels monolithic rather then
with lots of modules, so we're in good company if we choose to do the
I haven't compiled my own kernels for the XO yet, so I don't know how much
can be tweaked to reduce the size, but it looks like there is some room
for tweaking. however, the biggest benefits look like they would be in
cleaning up the userspace boot process. there is a _lot_ of stuff started
that may not be needed in the stable hardware environment of the XO laptop
where there is really only one program active at a time (dbus comes to
remember that XO is based on Fedora, which is designed for maximum
features and flexibility, not for efficiancy. This translates into poor
performance for the user.
I know that the XO has a slow CPU, but I just recently retired a 333MHz
laptop that I was running Slackware on, and it was far more responsive
then the XO is (even with a faster CPU and a solid-state drive). there is
a LOT of room for improvement here.
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