Re: Xen-4.3 and -unstable regression from changeset "numa-sched: leave node-affinity alone if not in 'auto' mode"

[George Dunlap <george.dunlap@eu.citrix.com>]

On 11/28/2013 12:31 PM, Andrew Cooper wrote:
> Hello,
>
> I have recently positivly identified
> b54a623efbcf5bff25c55117add1b4427b4e2f1b as causing a boot failure.
>
> Serial log is attached.  The crash is completely deterministic, and is
> from an IBM xSeries 3530 M4 server.
>
> Given the crash and bad patch, I suspect it is more to do with the
> NUMA/memory layout than the specifics of the server.
>
> Dario: Being your patch, do you have any ideas?

Do you have a xen-syms you can use to find out what line the crash 
happened at?

Dom0 should have auto_node_affinity set at this point; so before this 
patch you'd have:
  nodemask = NODEMASK_MASK_NONE;
  [set nodes in nodemask from cpumask]
  d->node_affinity=nodemask

After, you have:
  nodes_clear(d->node_affinity)
  [set nodes in d->node_affinity from cpumask]

Everything looks like it should be the same.

Can you try just reverting what's in the positive side of the if()? 
I.e., adding back in nodemask=NODE_MASK_NONE at the top, and the 
nodemask copying, and see what happens?

  -George