Re: Blkio: Apply two policies on one IO process

[Vivek Goyal <vgoyal@redhat.com>]

On Wed, Mar 30, 2011 at 12:00:16AM +0800, Lina Lu wrote:
> Hi Vivek,
>       As the weight and throttle policies are on different layers, someone can apply 
> these two policies on one IO pid at one time. And the IO bandwidth will be controlled
> with the more stringent policy.
>       If someone first set two policies on one pid, then want to remove the weight
> policy, he must first echo the pid to parent dir's tasks, then echo the throttle policy
> to parent dir's blkio.throttle_xx_xx_device. These steps seen to be cumbersome.
>       This is because the weight policy can be applied independence, but the throttle
> policy is always accompany with the weight policy(default 500). I think it will be 
> better that these policies are independent of each other. What is your opinion?
>       Additional, do you recommend applying two policies on one IO process?

How do you want to make these independent?

- If one does not want weight based policy, one can change IO scheduler
  to deadline.

- If one does not want throttling policy, do not apply throttling limits.

Thanks
Vivek