Modularize kernel

[Robert Watson]

On Fri, 8 Sep 2006, M. Warner Losh wrote:

> In message: <f126fae00609071949u79960am7d781b3fca8058b8 at mail.gmail.com>
>            "Howard Su" <howard0su at gmail.com> writes:
> : On 9/8/06, M. Warner Losh <imp at bsdimp.com> wrote:
> : > I routinely boot a minimal kernel and kldload everything.  this gives
> : > me a kernel about 1/3 the size of a full GENERIC build, but at the
> : > price of needing to keep my modules up to date.
> :
> : For -STABLE tree, i think it is easy since ABI is fixed. However what
> : I proposed is pushing this effort to let most user to use module
> : instead of rebuilding the kernel.
>
> I guess what I'm saying is that with a minimal kernel + all the modules we 
> have, you have that today.

One of the biggest concerns I have with moving towards a heavily modularized 
default kernel is that we may find we need to explore improving our automatic 
loading of modules.  For example, if we want to de-populate the base kernel 
with respect to device drivers, which take up quite a lot of space, we'll want 
to look both at how to handle early boot, and later loading if hardware turns 
up -- issues we've largely avoided by virtue of compiling them in.  We may, 
for example, want to look at Apple's approach of loading all the available 
modules sequentially early in the boot to see what attachs, unload the idle 
modules, and then provide demand loading later.

Robert N M Watson
Computer Laboratory
University of Cambridge