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.
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
This bug happens when paravirtualisation is enable in the kernel:
To fix it just recompile your kernel with CONFIG_PARAVIRT disabled.
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
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
change
$(MAKE) -f debian/rules.gen build-$(DEB_HOST_ARCH)
to
$(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.
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
References
Seems that it look for sata 2 even if none is present. A patch is ready and a kernel (2.6.18-9) is closed to be uploaded:
http://www.mail-archive.com/debian-kernel%40lists.debian.org/msg23269.html
A short answer is given by the maintener of klibc.
The symptoms were:
So what the fuck…
strace jarsigner ...
Looks like /dev/random is empty ! How can /dev/random be empty ?!
man 4 random
Ok so my entropy pool was empty and I just rebooted to full it up. I think it happened because of a previous kernel crash.
