Re: [opensuse-kernel] Re: [RFC] Simplifying kernel configurationfor distro issues

From: Steven Rostedt
Date: Thu Jul 19 2012 - 13:02:43 EST

On Thu, 2012-07-19 at 18:48 +0200, Borislav Petkov wrote:

> > Also, if you are building on another box than what the kernel is for,
> > you can go to that box and run 'lsmod > /tmp/lsmod'. Copy that file to
> > the build machine (into /tmp/lsmod), and then run
> > 'make LSMOD=/tmp/lsmod localmodconfig', and this will remove the modules
> > not used by the target box.
> Seriously, this helps only in the cases where the stuff the distro
> actually needs is in modules. So, there probably are obscure situations
> where you need to enable stuff which is bool and not M. Hopefully those
> cases are seldom enough so thanks for this, I'll try that the next time.

This is why I created the make-min-config in ktest. It keeps on
disabling configs to see what the machine needs to boot (and optionally
run some test), and what configs it can disable. It does not touch the
multi options though.

It creates two configs. One that has the configs that it can't turn off
(still enabled with a make allnoconfig, or selected by something that it
must have), and a config that just has the configs that 'if I disable
this, the box doesn't boot'.

Here's an example:

For my min-config files with the configs that couldn't be turned off:

$ wc -l config-min*
117 config-min
139 config-min-net

The config-min will get the box to boot (no network). The -net, adds
enough to ssh to the box.

$ wc -l config-skip*
11 config-skip
14 config-skip-net

The above are the configs that ktest found if it disabled, would not
boot (or ssh).

$ cat config-skip-net

I can pass the above to a allnoconfig, and the box will boot and allow
ssh. Note, the reason for the serial config, is that this ktest run uses
a serial port to see if the box booted. If the serial isn't there, then
it thinks it failed.

-- Steve

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