Improved INCLUDE_CONFIG_FILE

[Eric Anderson]

On 03/26/07 06:17, Peter Jeremy wrote:
> On 2007-Mar-25 23:55:26 -0500, Eric Anderson <anderson at freebsd.org> wrote:
>> On 03/25/07 09:34, Gavin Atkinson wrote:
>>> strings `sysctl -n kern.bootfile` | grep ^___ | sed -e 's/^___//'
>>>
>>> should still work if it was in a .comment section
>> Unless you no longer have the running kernel, or it has changed since 
>> the boot up of the system.  A sysctl knob to dump it is *very* useful.
> 
> Note that kern.bootfile will get updated during installkernel.  I also
> can't think of a situation where I would have lost all copies of my
> running kernel as well as the config file that was used to build it.
> This could potentially happen if you ran two or more installkernels
> without rebooting but I can't think of any reason why I would do that:
> If a kernel builds, I am likely to try booting it before going onto
> something else.  If a kernel doesn't build, it won't install.
> 
> Overall, having the config file loaded strikes me as a waste of RAM.
> 


As Larry mentioned, the kernel config file (say GENERIC) is about 10k 
uncompressed.  If it's bzipped or gzipped, as it is (including comments, 
etc) it ends up ~4k.  My kernel, is about 7500k (not far from GENERIC), 
so the additional .05% is probably not noticeable by anyone.

One reason you might not have the kernel lying around is because the 
system is net booted, so the kernel was sent across the network.  You 
might have many different kernel configs running, and the kernel file 
may not be available to the hosts.

Anyway, to me, the extra few kb in the kernel is not going to be 
noticeable by anyone except a small fraction of the users, and those 
users are already removing tons of stuff and have a very stripped down 
kernel anyhow.  So, they can have a "options NO_INCLUDE_CONFIG" that 
will save them the 4kb if they want.

It's hard for me to argue against having it in GENERIC, since the 
additional size is minimal (negligible actually), there are no adverse 
side affects, and there is great benefit for those of us who actually 
can think of situations where it would be helpful, and of course you can 
always optionally remove it.

Eric