[Nottingham] SUSE Self-compiled Kernel is huge

[Michael Quaintance]

To follow up, it seems the debug symbols were the problem.

Going into the "kernel hacking" sections of the menuconfig and turning off
everything related to debug symbols brought the new kernel to within 1 MB
of the original kernel (much more realistic). It seems Suse explicitly
strips the object files as a separate step (rather than turning symbols off
in the configuration) but the result is almost the same.

Thanks Mike for your suggestion, even though the instructions my friend was
using were functionally identical to what that guide suggests.

-Michael

On Thu, Jun 7, 2012 at 5:26 AM, Mike Martin <mike at redtux.org.uk> wrote:

> On 7 June 2012 08:02, Michael Quaintance <penfoldq at penfoldq.co.uk> wrote:
> > A friend of mine is stuck with using SUSE for a work project, he needs to
> > modify the stock kernel and so he followed the instructions from SUSE but
> > the resulting kernel is, in his words, gargantuan.
> >
> > Anyone got any ideas on what he has done wrong? Specifically, are there
> any
> > alternate make targets he should be using instead/as well?
> >
> > I've attached his own description of the problem below.
> >
> > Thanks in advance.
> >
> > -Michael
> >
> > -------------------------------------------------------
> >
> > I have an installation of SLES 11.2 on the x86_64 platform updated to the
> > 3.0.26-0.7 kernel.
> >
> > As a part of a project, I need to tweak the kernel configuration and
> apply a
> > minor patch to a few of the source files.
> >
> > I did the following (based mostly on the /usr/src/linux/README.SUSE
> file):
> >
> > Copy the source tree to my home directory:
> >
> > $mkdir -p ~/builds/kernel/linux-3.0.26-0.7/src
> > $cd ~/builds/kernel/linux-3.0.26-0.7/src
> > $cp -R /usr/src/linux-3.0.26-0.7/* .
> >
> > Clone the running system's configuration and then launch menuconfig to
> tweak
> > that:
> >
> > $make cloneconfig
> > $make menuconfig
> >
> > Make the following changes to the configuration:
> > *Change the local version string
> > *Enable the TCP MD5 option
> > *Enable IPv6 multicast routing
> > *Eanble IPv6 multicast multi-table support
> > *Enable IPv6 PIM-SM
> >
> > Make my changes to the sources
> > Build and install and make RPMs
> >
> > $make
> > $make modules_install
> > $make install
> > $make rpm-pkg
> >
> >
> > When I do this, the kernel I get is gargantuan compared to the binaries
> > provided by SUSE, even though I am supposedly using the same
> configuration
> > they used.
> >
> > For comparison:
> >
> > Their /lib/modules directory is about 91M, while mine is 1.8G
> > Their /lib/modules/kernel/drivers directory is about 60M, while mine is
> 1.3G
> > Their /lib/modules directory contains 2167 files while mine has 3772
> > Individual module files are much larger. For example, their
> > kernel/drivers/net/e1000/e1000.ko is 260K while mine is 2M.
> > Their initrd file is 7.1M while mine is 14M
> > Their vmlinuz...gz file is 4.3M while mine is 43M
> > The RPMs generated don't match. SUSE provided kernel-default,
> > kernel-default-base, kernel-devel, and linux-kernel-headers. I got only
> two
> > (kernel- and kernel-headers)
> > The sum total of the SUSE-provided kernel RPMs (kernel-default,
> > kernel-default-base, kernel-devel and linux-kernel-headers) is about 38M.
> > The sum of the two kernel RPMs I got is about 321M
> >
> >
> > I assume that my build is packed full of debug info and theirs isn't. Are
> > there alternate make targets I should be using?
> >
> > If there are no magic command line parameters to give make, then it would
> > appear that the config file I extracted from /proc/config.gz is not the
> one
> > SUSE used to compile their kernel. Or at least not for compiling all the
> > modules.
> >
> > What should I change in the configuration to bring my build down to a
> > reasonable size? There are many symbol/debug options, but I don't want to
> > just go randomly flipping switches trying to find the magic combination
> SUSE
> > used.
> have a look at this
>
> http://www.howtoforge.com/kernel_compilation_suse_p2
>
> I would guess you should have a config file in /boot and you should
> use that as a base
>
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