cgroup NAKs ignored? Re: [PATCHSET RFC cgroup/for-4.6] cgroup, sched: implement resource group and PRIO_RGRP

From: Ingo Molnar
Date: Sat Mar 12 2016 - 12:13:28 EST

* Mike Galbraith <umgwanakikbuti@xxxxxxxxx> wrote:

> On Sat, 2016-03-12 at 07:26 +0100, Mike Galbraith wrote:
> > On Fri, 2016-03-11 at 10:41 -0500, Tejun Heo wrote:
> > > Hello,
> > >
> > > This patchset extends cgroup v2 to support rgroup (resource group) for
> > > in-process hierarchical resource control and implements PRIO_RGRP for
> > > setpriority(2) on top to allow in-process hierarchical CPU cycle
> > > control in a seamless way.
> > >
> > > cgroup v1 allowed putting threads of a process in different cgroups
> > > which enabled ad-hoc in-process resource control of some resources.
> BTW, within the scheduler, "process" does not exist. [...]

Yes, and that's very fundamental.

And I see that many bits of the broken 'v2' cgroups ABI already snuck into the
upstream kernel in this merge dinwo, without this detail having been agreed upon!

Tejun, this _REALLY_ sucks. We had pending NAKs over the design, still you moved
ahead like nothing happened, why?!

> [...] A high level composite entity is what we currently aggregate from
> arbitrary individual entities, a.k.a threads. Whether an individual entity be
> an un-threaded "process" bash, a thread of "process" oracle, or one of
> "process!?!" kernel is irrelevant. What entity aggregation has to do with
> "process" eludes me completely.
> What's ad-hoc or unusual about a thread pool servicing an arbitrary number of
> customers using cgroup bean accounting? Job arrives from customer, worker is
> dispatched to customer workshop (cgroup), it does whatever on behest of
> customer, sends bean count off to the billing department, and returns to the
> break room. What's so annoying about using bean counters for.. counting beans
> that you want to forbid it?

Agreed ... and many others expressed this concern as well. Why were these concerns