Since version 49 compcache (ramzswap) is a part of kernel-power, the instructions bellow are not needed and shall be used just as a reference

Here is how to make compcache working on n900. You will need scratchbox or madde environment ready for kernel compilation

1. download latest (48) kernel power source in directory of your choice
apt-get source kernel-power

2. unzip and copy attached patches (update_mmu_cache_arm.zip and patch_swap_notify_core_support_2_2.6.28.zip) into kernel-power-2.6.28\debian\patches

3.add update_mmu_cache_arm.diff at the end of series file

cd kernel-power-2.6.28/debian/patches/
echo update_mmu_cache_arm.diff >> series

4.add patch_swap_notify_core_support_2_2.6.28.diff at the end of series file

cd kernel-power-2.6.28/debian/patches/
echo patch_swap_notify_core_support_2_2.6.28.diff >> series

4. goto kernel source directory and build kernel package
dpkg-buildpackage -rfakeroot -b

5. unzip compcache source(compcache-0.6.2.zip) into the same directory you've downloaded kernel sources

6. cd into compcache-0.6.2 and make it

at that point you should have patched kernel .debs and ramzswap.ko for that kernel. Install kernel on the device and copy ramzswap.ko in /lib/modules/2.6.28.10-power48

reboot and use instructions here
in short it is something like

insmod /lib/modules/current/ramzswap.ko disksize_kb=65536
swapon /dev/ramzswap0
swapoff /dev/mmcblk0p3; swapon /dev/mmcblk0p3



Notifications are working, but seems there are paths in the kernel swap subsystem allowing direct write over a page without first marking it free.
Seems like memory consumption should not be affected by that.

I've disabled nokia swap page remapping (for performance reasons), will enable it again if swap fragmentation develops over time to see if it could help.


EDIT: changed recommended disksize_kb to 120512