Hi, folks.
With the aid of Jonathan's and Philipp's excellent instructions I was
able to rebuild the Debian Wheezy 3.2 kernel with the NSS feature enabled.
As I have begun to experiment with building the kernel, I have found the
following issues with the Debian process
1) If I install the libncurses5-dev package and use the instructions
found in Chapter 4, Section 5 of the Debian Linux Kernel Handbook (i.e.,
the make menuconfig, make clean, make deb-pkg steps), the kernel built
is for the s390 architecture and not the s390x one.
2) If I use the make menuconfig command instead of the two
scripts/config commands shown below, then the next fakeroot make -f
debian/rules.gen binary-arch_s390x_none_s390x command fails with an
error. That is the following sequence does not work:
cd linux-3.2.23
fakeroot make -f debian/rules.gen setup_s390x_none_s390x
make menuconfig
fakeroot make -f debian/rules.gen binary-arch_s390x_none_s390x
3) Since it appears that I can not use the make menuconfig process to
update the kernel configuration file, where might I find a list of all
acceptable options for the scripts/config --enable command
4) Why is the kernel build process for s390x different than the one
documented in the Handbook?
Thanks again for the help, and have a good one, too.
DJ
On 10/25/2012 05:17 PM, Philipp Kern wrote:
Hi,
On Tue, Oct 23, 2012 at 08:45:25PM -0700, Jonathan Nieder wrote:
Dave Jones wrote:
Can the wheezy s390x kernel be saved as an NSS? If so, how?
Based on [1], it looks like the answer is currently no, based on the
following line in the kernel config file:
# CONFIG_SHARED_KERNEL is not set
The description of that option says
Select this option, if you want to share the text segment of the
Linux kernel between different VM guests. This reduces memory
usage with lots of guests but greatly increases kernel size.
You can build a custom kernel using that option if you wish. It works
like this[2]:
$ apt-get source linux
# apt-get install build-essential fakeroot
# apt-get build-dep linux
$ cd linux-version
$ fakeroot debian/rules source
$ fakeroot make -f debian/rules.gen setup_s390_none_s390x
as we're talking about s390x here that would be setup_s390x_none_s390x.
$ cd debian/build/build_s390_none_s390x
Same here.
$ scripts/config --disable DEBUG_INFO
$ scripts/config --enable SHARED_KERNEL
That's «../source_none/scripts/config».
$ cd ../../..
$ fakeroot make -f debian/rules.gen binary-arch_s390_none_s390x
And again s390x_none_s390x instead of s390_none_s390x.
I just did the recompilation. AFAICS the kernel size is indeed increased quite
a bit. We currently have:
-rw-r--r-- root/root 6303232 2012-10-22 15:36 ./boot/vmlinuz-3.2.0-4-s390x
With SHARED_KERNEL on and DEBUG_INFO off as above:
-rw-r--r-- root/root 7945728 2012-10-25 21:53 ./boot/vmlinuz-3.2.0-4-s390x
So a NSS shareable kernel is 1.26 times larger than a plain one. And I fear
that the additional bits cannot be discarded at runtime neither, but I cannot
test this right now.
Interestingly enough the kernel is already in its plain form 2.23 times bigger
than an amd64 build of vmlinuz-3.2.0-3-amd64.
Kind regards
Philipp Kern
[1] http://www.vm.ibm.com/linux/linuxnss.html
[2] http://kernel-handbook.alioth.debian.org/ch-common-tasks.html
--
Dave Jones
V/Soft Software
www.vsoft-software.com
Houston, TX
281.578.7544
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