Re: config(5) break down

[Masao Uebayashi <uebayasi%gmail.com@localhost>]

2010/3/16 Wojciech A. Koszek <wkoszek%freebsd.org@localhost>:
> On Tue, Mar 16, 2010 at 06:55:36AM +0900, Masao Uebayashi wrote:
>> On Tue, Mar 16, 2010 at 1:57 AM, Eduardo Horvath <eeh%netbsd.org@localhost> 
>> wrote:
>> > On Sun, 14 Mar 2010, Wojciech A. Koszek wrote:
>> >
>> >> I was wondering how does Linux/Solaris kernel build system work in terms 
>> >> of
>> >> opt_*.h files?  Do they have some alternative solutions for #ifdef's 
>> >> based on
>> >> what has been included into the kernel at configuration time?
>> >
>> > It's been a while since I poked around with Linux, but I think they have a
>> > single file that contains all that info.
>>
>> My understanding is splitting opt_*.h into small files is just only to
>> save rebuild time.  Is this right?  It's also same as GNU Autoconf +
>> configure + #include "config.h" do.
>
> I think it is also for narrowing the impact of particular options; it tends to
> act as a sort of layering and encapsulation. And saves a bit of confusion when
> a commiter enabled his debugging facility with DEBUG, which may not be unique.
>
>> > And since everything is compiled separately you can often just replace one
>> > module with another one that is compiled with DEBUG turned on.
>> > Without rebooting the machine.  (Certain inter-module interfaces are
>> > affected by DEBUG while others are not.  YMMV.)
>>
>> Thanks, and this is also pretty much expected too.  IIRC Windows did
>> similar thing; providing foo.dll & foodbg.dll.  I think this strategy
>> (== providing normal+debug binaries as official module binaries) would
>> work for us too.
>
> You mean that the delivery of two versions of each kernel module could 
> eventually
> solve the problem for you?

The basic rule is to distribute single binaries of kernel / modules.
I meant that providing debug modules exceptionally might make sense,
because Windows camp does that, and it seems working.  (This is just
an idea, not important.  So never mind anyway.)

Masao