Re: [PATCH 00/10] cgroups: Task counter subsystem v8

[Rik van Riel]

On 02/01/2012 02:51 PM, Andrew Morton wrote:
> On Wed, 1 Feb 2012 19:50:01 +0100
> Frederic Weisbecker<fweisbec@xxxxxxxxx>  wrote:
>
> > On Wed, Feb 01, 2012 at 08:31:26AM -0800, Tejun Heo wrote:
> > > On Wed, Feb 01, 2012 at 04:37:40AM +0100, Frederic Weisbecker wrote:
> > > > Changes In this version:
> > > >
> > > > - Split 32/64 bits version of res_counter_write_u64() [1/10]
> > > >    Courtesy of Kirill A. Shutemov
> > > >
> > > > - Added Kirill's ack [8/10]
> > > >
> > > > - Added selftests [9/10], [10/10]
> > > >
> > > > Please consider for merging. At least two users want this feature:
> > >
> > > Has there been further discussion about this approach?  IIRC, we
> > > weren't sure whether this should be merged.
> >
> > The doubts I have noticed were:
> >
> > Q: Can't we rather focus on a global solution to fight forkbombs?
> >
> > If we can find a reliable solution that works in any case and that
> > prevent from any forkbomb to impact the rest of the system then it
> > may be an acceptable solution. But I'm not aware of such feature.
> >
> > Besides, another point in having this task counter is that we
> > have a per container limit. Assuming all containers are running under
> > the same user, we can protect against a container starving all others
> > with a massive amount of processes close to the NR_PROC rlimit.

> What I struggle with is "is this feature useful enough to warrant
> merging it"?

I have seen thunderbird create as many child processes
as it could (until I hit my rlimit NR_PROC), and have
seen web servers go wrong under a combination of load
and buggy scripts, forking as many processes as they
could.

Since we know rlimit NR_PROC is useful, having the
equivalent per cgroup will be useful, too.

What we need to lose is the focus on malicious
forkbombs - buggy programs are a real issue, and
protecting against them is useful.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/