Re: [PATCHSET block/for-next] IO cost model based work-conserving porportional controller

[Paolo Valente]

> Il giorno 14 giu 2019, alle ore 19:56, Tejun Heo <tj@xxxxxxxxxx> ha scritto:
> 
> On Thu, Jun 13, 2019 at 06:56:10PM -0700, Tejun Heo wrote:
> ...
>> The patchset is also available in the following git branch.
>> 
>> git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-iow
> 
> Updated patchset available in the following branch.  Just build fixes
> and cosmetic changes for now.
> 
>  git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-iow-v2
> 

Hi Tejun,
I'm running the kernel in your tree above, in an Ubuntu 18.04.

After unmounting the v1 blkio controller that gets mounted at startup
I have created v2 root as follows

$ mount -t cgroup2 none /cgroup

Then I have:
$ ls /cgroup
cgroup.controllers  cgroup.max.descendants  cgroup.stat             cgroup.threads  io.weight.cost_model  system.slice
cgroup.max.depth    cgroup.procs            cgroup.subtree_control  init.scope      io.weight.qos         user.slice

But the following command gives no output:
$ cat /cgroup/io.weight.qos 

And, above all,
$ echo 1 > /cgroup/io.weight.qos 
bash: echo: write error: Invalid argument

No complain in the kernel log.

What am I doing wrong? How can I make the controller work?

Thanks,
Paolo

> Thanks.
> 
> -- 
> tejun