Posts Tagged ‘Linux’

Which glibc version for my Linux kernel ?

November 30, 2014 Leave a comment

Here is a sum up of glibc kernel headers requirements taken from glibc README git history.

glibc version Linux headers version requirement
2.26, 2.27 3.2 or later
2.24 to 2.25 2.6.32 or later for i[4567]86 and x86_64, 3.2 or later for other architecture
2.20 to 2.23 2.6.32 or later
2.17 to 2.19 2.6.16 or later
2.4 to 2.16 2.6.0 or later, make check fail if < 2.6.16

Updated on 2018-06-26

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Linux memory compression

September 20, 2008 Leave a comment

With Linux it’s possible de compress the memory to limit disk swapping. A compressed swap can be created in memory. It was implemented in linuxcompressed project available on sourceforge, but this project died in 2003. It has respawned some month ago as compcache, on Google Code. The 0.4 version perfectly build and load in my Debian 2.6.26 kernel.


Linux memory and Slab

November 27, 2007 Leave a comment

I found that my Slab (a kind of kernel heap) was growing up to 250Mb:

cat /proc/meminfo | grep Slab

As shown by /proc/slabinfo and slabtop, the responsible were dentry and ext3_inode_cache. I found a solution here:

echo 2 > /proc/sys/vm/drop_caches


modpost: GPL-incompatible module xxx.ko uses GPL-only symbol ‘paravirt_ops’

April 28, 2007 1 comment

This bug happens when paravirtualisation is enable in the kernel:

To fix it just recompile your kernel with CONFIG_PARAVIRT disabled.

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make-kpkg good parameters

April 28, 2007 Leave a comment

I had troubles to find the good append-to-version and revision parameters to create packages which match the official ones:

fakeroot make-kpkg --revision 2.6.20-3jerome1 --append-to-version -1-686 --subarch 686 --initrd binary-arch

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Compile a kernel in the debian with dpkg-buildpackage

April 21, 2007 Leave a comment

Here is how to compile a debian way kernel using the apt-get source/dpkg-buildpackage way:

apt-get source linux-2.6-2.6.20
cd linux-2.6-2.6.20
vim debian/rules


$(MAKE) -f debian/rules.gen build-$(DEB_HOST_ARCH)


$(MAKE) -f debian/rules.gen build-i386-none-686-real

It will avoid to build for all architecture (486, k7, vserver …). Now create the package.

dch -i
fakeroot dpkg-buildpackage -d -b

To conclude I see no reason to use this method, make-kpkg is better.

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Linux I/O scheduler

February 13, 2007 Leave a comment

By default, starting with Linux 2.6.18, the default I/O scheduler is CFQ. If you are more interested in having short response times in you GUIs than high I/O disc throughput, you may try to change it:

echo anticipatory > /sys/block/sda/queue/scheduler