What setting from /proc /sys file system cause pdflush, kswapd0 or kblockd to periodically at write data on /,/home/ and /tmp partitions at 2-3 minutes in idle mode (reported by iostat). Strangely nothing is written on swap partition.

I try different setting in /proc/sys/vm or remount ext3 partitions with noatime,commit=43200 parameters but nothing changed.

Kernel used is 2.6.18