[openstack-dev] [nova] NUMA Cells

Daniel P. Berrange berrange at redhat.com
Thu Dec 4 12:46:00 UTC 2014

On Thu, Dec 04, 2014 at 09:25:00AM +0100, Nikola Đipanov wrote:
> On 12/04/2014 05:30 AM, Michael Still wrote:
> > Hi,
> > 
> > so just having read a bunch of the libvirt driver numa code, I have a
> > concern. At first I thought it was a little thing, but I am starting
> > to think its more of a big deal...
> > 
> > We use the term "cells" to describe numa cells. However, that term has
> > a specific meaning in nova, and I worry that overloading the term is
> > confusing.
> > 
> > (Yes, I know the numa people had it first, but hey).
> > 
> > So, what do people think about trying to move the numa code to use
> > something like "numa cell" or "numacell" based on context?
> > 
> Seeing that "node" is also not exactly unambiguous in this space - I am
> fine with both with either "numanode" or "numacell" with a slight
> preference for "numacell".
> A small issue will be renaming it in objects though - as this will
> require adding a new field for use in Kilo while still remaining
> backwards compatible with Juno, resulting in even more compatibility
> code (we already added some for the slightly different data format). The
> whole name is quite in context there, but we would use it like:
>   for cell in numa_topology.cells:
>      # awesome algo here with cell :(
> but if we were to rename it just in places where it's used to:
>   for numacell in numa_topology.cells:
>      # awesome algo here with numacell :)

I think renaming local variables like this is really a solution
in search of a problem. It is pretty blindingly obvious the 'cell'
variable refers to a NUMA cell here, without having to spell it
out as 'numacell'. Likewise I think the object property name is
just fine as 'cell' because the context again makes it obvious
what it is referring to

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