Messages in this thread | | | Date | Thu, 1 Feb 2018 11:57:10 -0800 | From | Tejun Heo <> | Subject | Re: [PATCH v4.15-rc9] sched, cgroup: Don't reject lower cpu.max on ancestors |
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Hello,
On Thu, Feb 01, 2018 at 05:49:42PM +0100, Peter Zijlstra wrote: > > Well, they're upper limits, not strict allocations. The current > > behavior implemented by cpu isn't either a strict allocation or upper > > limits. It disallows a child from having a value higher than the > > parent (allocation-ish) but the sum of the children is allowed to > > exceed the parent's (limit-ish). > > True; but its still weird to have the parent 'promise' something and > then retract that 'promise' later.
Yeah, depending on how you look at it, it can feel weird. It's just that viewing these absolute resource limits (cpu.max, memory.{high,max}, io.max, pids.max) as upper bounds seems to be the best abstraction in terms of capturing what they do and making uses of them in a robust way.
> > We had this sort of input validations in different controllers all in > > their own ways. In most cases, these aren't well thought out and we > > can't support things like delegation without aligning controller > > behaviors. > > I suppose.. > > Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Will route it through cgroup fixes branch in a week or so.
Thanks a lot.
-- tejun
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