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Date:      Mon, 26 Mar 2007 06:42:01 -0500 (CDT)
From:      Larry Rosenman <ler@lerctr.org>
To:        Peter Jeremy <peterjeremy@optushome.com.au>
Cc:        freebsd-current@freebsd.org
Subject:   Re: Improved INCLUDE_CONFIG_FILE
Message-ID:  <20070326063907.G59155@thebighonker.lerctr.org>
In-Reply-To: <20070326111702.GD838@turion.vk2pj.dyndns.org>
References:  <20070324113739.GA41119@ravenloft.kiev.ua> <20070324135333.GA86105@FreeBSD.czest.pl> <20070324153108.P4956@fledge.watson.org> <20070324220041.GI847@turion.vk2pj.dyndns.org> <20070324233307.GA93841@FreeBSD.czest.pl> <20070325153013.E77473@ury.york.ac.uk> <4607523E.50201@freebsd.org> <20070326111702.GD838@turion.vk2pj.dyndns.org>

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On Mon, 26 Mar 2007, Peter Jeremy wrote:

> On 2007-Mar-25 23:55:26 -0500, Eric Anderson <anderson@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.

I had a weird situation where the /usr/src directory got trashed, but the 
system was still up.  I did *NOT* have a good copy of the config so had
to recreate it.

Configs are generally between 4 & 8K, so we're talking 1-2 (maybe 3) pages
of memory.  In the whole scheme of things, it's not a lot of memory, and
would be VERY useful in the case of stupidity like the above, and for other
reasons stated upthread.

We waste far more memory on other things in the system.  1-3 pages for this
kind of USEFUL info is not a waste IMHO.


LER
-- 
Larry Rosenman                     http://www.lerctr.org/~ler
Phone: +1 512-248-2683                 E-Mail: ler@lerctr.org
US Mail: 430 Valona Loop, Round Rock, TX 78681-3893



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