Re: [PATCH v1 0/2] genirq: support multiple IRQ notifier.

[Christoph Hellwig]

On Fri, Mar 25, 2016 at 08:51:51AM -0700, Weongyo Jeong wrote:
> Each irq_desc only supports one IRQ affinity notifier at current
> implementation so when we try to register another notifier, it silently
> unregister previous entry and register new one.
> 
> However the problem is that if CONFIG_RFS_ACCEL is set, at current
> implementation no way to set additional IRQ affinity notifier for
> some NIC cards RFS enabled because it already used for RFS.
> With this patch we can register multiple IRQ affinity notifiers.

The whole concept of these irq affinity notifiers seems wrong to me.

If a device supports MSI-X it should simply request per-cpu or per-node
vectors and we should prevent affinity changes for them.