[dm-devel] Re: [PATCH 6/7] bio-cgroup: Implement the bio-cgroup

[Takuya Yoshikawa <yoshikawa takuya oss ntt co jp>]

Hi Tsuruta-san,

Ryo Tsuruta wrote:
> Hi Yoshikawa-san,
>
> > > +static void bio_cgroup_move_task(struct cgroup_subsys *ss,
> > > +				struct cgroup *cont,
> > > +				struct cgroup *old_cont,
> > > +				struct task_struct *p)
> > > +{
> > > +	struct mm_struct *mm;
> > > +	struct bio_cgroup *biog, *old_biog;
> > > +
> > > +	if (bio_cgroup_disabled())
> > > +		return;
> > > +
> > > +	mm = get_task_mm(p);
> > > +	if (mm == NULL)
> > > +		return;
> > > +
> > > +	biog = cgroup_bio(cont);
> > > +	old_biog = cgroup_bio(old_cont);
> > > +
> > > +	mmput(mm);
> > > +	return;
> > > +}
> > Is this function fully implemented?
>
> This function can be more simplified, there is some unnecessary code 
> from old version.

I think it is neccessary to attach the task p to new biog.

> > I tried to put a process into a group by writing to
> > "/cgroup/bio/BGROUP/tasks" but failed.
>
> Could you tell me what you actually did? I will try the same thing.
>
> --
> Ryo Tsuruta <ryov valinux co jp>

I wanted to test my own scheduler which uses bio tracking information.
SO I tried your patch, especially, get_bio_cgroup_iocontext(), to get
the io_context from bio.

In my test, I made some threads with certain iopriorities run 
concurrently. To schedule these threads based on their iopriorities,
I made BGROUP directories for each iopriorities.
e.g. /cgroup/bio/be0 ... /cgroup/bio/be7
Then, I tried to attach the processes to the appropriate groups.

But the processes stayed in the original group(id=0).
...

I am sorry but I have to leave now and I cannot come here next week.
--> I will take summer holidays.

I will reply to you later.

Thanks,
- Takuya Yoshikawa