Re: [PATCH -mm] cgroup: Fix task counter common ancestor logic

From: KAMEZAWA Hiroyuki
Date: Tue Nov 08 2011 - 18:59:50 EST


On Tue, 8 Nov 2011 13:51:11 -0800
Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Tue, 8 Nov 2011 16:21:10 +0100
> Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:
>
> > To solve this, keep the original cgroup of each thread in the thread
> > group cached in the flex array and pass it to can_attach_task()/attach_task()
> > and cancel_attach_task() so that the correct common ancestor between the old
> > and new cgroup can be safely retrieved for each task.
>
> OK, thanks.
>
> We need to work out what to do with this patchset. ie: should we merge
> it. I'm not sure that the case has been made?
>

My impression is positive....but as other guy proposed, I feel fork-limit
should be useful, too. It allows to limit or rate-limit the number of fork().
So, I wonder some fork-limit can be implemented in this task_counter cgroup.

> Let's please drag this thing onto the table and poke at it for a while.
> Probably everyone has forgotten everything so we'll need to start
> again, sorry. Perhaps you can (re)start proceedings by telling us why
> it's useful to our users and why we should merge it?
>
please ;)

>
> Some mental notes:
>
> Tim says it would be useful for the things he's doing but doesn't
> appear to have confirmed/tested that.
>
> Kay has said that it would not be useful for his plumber's wishlist
> item, which is a shame.
>
> I seem to recall complaining that it doesn't address the forkbomb issue
> for non-cgroups setups, so the forkbomb issue remains unaddressed.

For non-cgroup fork-bomb, I and Minchan proposed forkbomb-killer (in
independent way). I stop it now but if someone has interests, I
recall it from grave.

Thanks,
-Kame







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