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[Launchpad Bug Tracker <1528325@xxxxxxxxxxxxxxxxxx>]

[Expired for OpenStack Compute (nova) because there has been no activity
for 60 days.]

** Changed in: nova
       Status: Incomplete => Expired

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https://bugs.launchpad.net/bugs/1528325

Title:
  instance with explicit "small" pages treated different from implicit

Status in OpenStack Compute (nova):
  Expired

Bug description:
  In numa_get_constraints() we call

  pagesize = _numa_get_pagesize_constraints(flavor, image_meta)

  then later we have

  if nodes or pagesize:
      <skip>
      [setattr(c, 'pagesize', pagesize) for c in numa_topology.cells]

  
  This ends up treating an instance which doesn't specify pagesize (which results in 4K pages) differently from an instance that explicitly specifies 4K pages.  In the first case the instance may not have a numa topology specified, while in the second case it does.

  In _get_guest_numa_config() we check whether the guest has a numa
  topology, and if it does we restrict it to a single NUMA node rather
  than letting it float across the whole host.  This unexpectedly
  results in different CPU and memory affinity depending on whether an
  instance implicitly assumes 4K pages or explicitly specifies them.

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