Re: Change to kernel+modules build approach

M. Warner Losh wrote:
> In message: <XFMail.20030814110100.jhb_at_FreeBSD.org>
>             John Baldwin <jhb_at_freebsd.org> writes:
> : 
> : On 14-Aug-2003 Ruslan Ermilov wrote:
> : > On Thu, Aug 14, 2003 at 02:10:19AM -0600, Scott Long wrote:
> : >> Luoqi Chen wrote:
> : > [...]
> : >> >On the other hand, all modules should create all the opt_*.h files
> : >> >it needs when built individually. Add opt_ddb.h to nullfs's Makefile
> : >> >should fix the breakage.
> : >> >
> : >> Our kernel build system isn't set up to handle passing config options
> : >> to modules.  Various solutions to this have been proposed, but nothing
> : >> has appeared yet.  In 5.x, we document that modules will not work with
> : >> PAE.
> : >> 
> : > How does the below look?  This is basically a more generic implementation
> : > of Luoqi's idea, but for -CURRENT:
> : 
> : I would prefer something far more radical that would involve moving
> : all the module metadata to sys/conf (i.e. removing sys/modules) and
> : building all the modules based on a single kernel config file.
> 
> Does that mean that we're abandoning the idea that modules will work
> with all kernels?  I don't disagree with the metadata move, since it
> is duplicated in two places now and allows for some more interesting
> subsettting, but I'm concerned that our third party ISVs will need to
> generate N different modules for the system...
> 
> Warner

I can tell you first hand that this is painful.  However, in the case of
PAE, it's somewhat neccessary since certain fundamental types change
size.  I can envision solutions for this, but I'm not sure if they are
less painful than just dealing with multiple module builds.

Scott