Messages in this thread | | | Date | Wed, 29 Oct 2014 09:16:40 +0100 | From | Peter Zijlstra <> | Subject | Re: Cache Allocation Technology Design |
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On Tue, Oct 28, 2014 at 11:22:15PM +0000, Matt Fleming wrote: > On Fri, 24 Oct, at 12:53:06PM, Peter Zijlstra wrote: > > > > NAK, cgroups must support full hierarchies, simply enforce that the > > child cgroup's mask is a subset of the parent's. > > For the specific case of Cache Allocation, if we're creating hierarchies > from bitmasks, there's a very clear limit to how we can divide up the > bits - we can't support an indefinite number of cgroup directories. > > What do you mean by "full hierarchies"?
Ah, so one way around that is to only assign a (whats the CQE equivalent of RMIDs again?) once you stick a task in.
But basically it means you need to allow things like:
root/virt/more/crap/hostA /hostB /sanityA /random/other/yunk
Now, the root will have the entire bitmask set, any child, say virt/more/crap can also have them all set, and you can maybe only start differentiating in the /host[AB] bits.
Whether or not it makes sense, libvirt likes to create these pointless deep hierarchies, as do a lot of other people for that matter.
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