Re: [PATCH] xen: postpone updating domains' node affinity when removing a CPU from a cpupool

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

On 03/09/2015 04:49 PM, Dario Faggioli wrote:
> 93be8285 ("update domU's node-affinity on the cpupool_unassign_cpu()
> path")  does the right thing, but does it too early. In fact, it
> is necessary to call domain_update_node_affinity() when a pCPU is
> removed from a cpupool, but that must happen after the pCPU is
> really gone from there.
> 
> More specifically, it is important that the update happens not
> before cpu_disable_scheduler() is called on that pCPU, to give
> that function the chance to fixup the vCPU affinity of the
> domains residing in the cpupool, if that is necessary.

It looks like domain_update_node_affinity() is already called for each
domain in the cpupool in cpu_disable_scheduler().  It doesn't look like
there should be a need to call it twice.  Can we just remove the call to
domain_update_node_affinity() in cpupool_unassign_cpu() and not add it back?

 -George