Swapping in 2.6.26-rc1 oddities (but it is omnipresent bug)

[Lukas Hejtmanek <xhejtman@ics.muni.cz>]

Hello,

I noticed that doing backup with rsync on my laptop from a local disk to a usb
disk swaps out many processes. To advice of Jiri Slaby (cc:), I did some
vmstat dumps.

More precisely, I run:
i=0; while true; do cat /proc/vmstat > vmstat.$i; sleep 3; i=$[$i+1]; done

and in parallel, I run the rsync to make the backup.

The vmstats can be found here:
http://www.fi.muni.cz/~xhejtman/vmstat/
(tar ball included at the end).

Jiri stated that the kernel begins to swap (somewhere around vmstat.50) even
if there are 70000 free pages.

Any ideas?

It more likely starts to swap the applications if I do not touch the laptop
(actively using Firefox or something like).

Also, the memory is occupied by disk caches not by the applications, so
I think it should not be swapped.

Moreover:
$ cat /proc/sys/vm/swappiness 
0

$ cat /proc/sys/vm/dirty_writeback_centisecs 
499

-- 
Lukáš Hejtmánek