Re: [PATCH RFC 0/2] add nproc cgroup subsystem

Tejun Heo
2015-03-02T13:54:21Z

On Tue, Mar 03, 2015 at 12:31:19AM +1100, Aleksa Sarai wrote:
> > If 16-bit PID's aren't a concern anymore, then why do we still default to
> > treating it like a 16-bit signed int (the default for
> > /proc/sys/kernel/pid_max is 32768)?
>
> I just want to emphasise that *even if* we changed to another default
> limit, the mere existence of a system-wide pid_max makes PIDs a
> resource.

We seem to fail to communicate. The primary reason why pid promotes
itself to a global resource status is because it's globally capped way
below its backing resource's (kernel memory) limit and it is very
difficult to make it not so due to direct userland dependencies on it.

Thanks.

--
tejun