Hi Vivek,

> How does your ioband setup looks like. Have you created at least one more
> competing ioband device? Because I think only in that case you have got
> this ad-hoc logic of waiting for the group which has not finished the
> tokens yet and you will end up buffering the bio in a FIFO.

I created two ioband devices and ran the dd commands only on the first
device.

> Do let me know if you think there is something wrong with my
> configuration.

From a quick look at your configuration, there seems to be no problem.

> Can you also send bio-cgroup patches which apply to 2.6.30-rc1 so that
> I can do testing for async writes.

I've just posted the patches to related mailing lists. Please try it.

> Why have you split the regular patch and bio-cgroup patch? Do you want
> to address only reads and sync writes?

For the first step, my goal is to merge dm-ioband into device-mapper,
and bio-cgroup is not necessary for all situations such as bandwidth
control on a per partition basis.

I'll also try to do more test and report you back.

Thank you for your help,
Ryo Tsuruta