Re: /proc/config reducing kernel image size

[DervishD <lkml@dervishd.net>]

    Hi Tom :)

 * Tom Fredrik Blenning Klaussen <bfg-kernel@blenning.no> dixit:
> There is no point in storing all the comments and unused options in the
> kernel image. This typically reduces the config size to about 1/5th
> before compressing, and to about 1/4th after compressing.

    I'm with you in that there is no point in storing the comments,
but I disagree about the unused options. Storing the unused options
as comments is more useful than it seems ;)

    Look at this example. You want to know if you have 'CONFIG_PNP'
enabled, so you do something like 'grep CONFIG_PMP /proc/config' (the
typo PNP->PMP is intended here). Of course that commands doesn't
print anything due to the typo. If you store the disabled options as
comments and a grep fails, you probably mispelled the config option,
or you're referring to a config option not present in your old
kernel, but if you remove them and you mispell the config option
there is no (automatic) way of knowing if you made a typo or if the
option is disabled. Any automatic search can, potentially, give you a
false negative.

    I'm not really sure about it, but I think that the unset options
are left as comments for the sake of automation. The space saving
doesn't (IMHO) worth the pain.

> I've also added the configuration option of how you want to compress it.

    Compression is always welcome, I suppose ;) Thanks for the idea.

    Raúl Núñez de Arenas Coronado

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