Re: [PATCH 4/5] virtio_net: add dedicated XDP transmit queues

On Fri, 2016-11-18 at 18:57 -0800, Jakub Kicinski wrote:

On Fri, 18 Nov 2016 18:43:55 -0800, John Fastabend wrote:

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On 16-11-18 06:10 PM, Jakub Kicinski wrote:

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On Fri, 18 Nov 2016 13:09:53 -0800, Jakub Kicinski wrote:  

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Looks very cool! :)

On Fri, 18 Nov 2016 11:00:41 -0800, John Fastabend wrote:  

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Is num_online_cpus() correct here?  

Sorry, I don't know the virto_net code, so I'm probably wrong.  I was
concerned whether the number of cpus can change but also that the cpu
mask may be sparse and therefore offsetting by smp_processor_id()
into the queue table below could bring trouble.
  

Seem like a valid concerns to me how about num_possible_cpus() instead.

That would solve problem 1, but could cpu_possible_mask still be sparse
on strange setups?  Let me try to dig into this, I recall someone
(Eric?) was fixing similar problems some time ago.

nr_cpu_ids is probably what you want ;)