pdflush cpu spikes since upgrading to 2.6.8 -system unusable

[trick]

I just upgraded from gentoo-dev-sources-2.6.5-r1 to gentoo-dev-sources-2.6.8-r10. After the upgrade, some kernel process named pdflush has started using lots of cpu in short bursts at random intervals, up to 10 times a minute or so at the worst. This also happens when the system is otherwise idle after stopping mostly everything.

This is extremely annoying because it causes everything to be sluggish in the time pdflush does whatever it is it does, even the mouse pointer gets unresponsive (kind of bad when you're doing graphics). Music and video playback skips. Key presses and mouse clicks don't always register (or double-register) during a cpu burst. So, basically I can't make graphics, listen to music, watch videos and dvds, write code and/or e-mail, or even browse the web properly because of this.

Anyone know how to solve this problem ?

If not, does anyone have an ebuild for gentoo-dev-sources-2.6.5 ? It's gone from portage, and I unmerged the 2.6.5 source before since I'm currently very low at disk space. Still have the kernel binary, but the nvidia driver seems to have been magically uninstalled from 2.6.5 behind my back when I upgraded (portage bug ?) and it requires the kernel source to install =(

- Gerry