Re: [RFC net-next 0/6] Cleanup IRQ affinity checks in several drivers

[Shay Drori <shayd@nvidia.com>]

On 15/08/2024 13:22, Joe Damato wrote:
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> 
> On Wed, Aug 14, 2024 at 05:20:46PM -0700, Jakub Kicinski wrote:
>> On Wed, 14 Aug 2024 19:01:40 +0100 Joe Damato wrote:
>>> If it is, then the only option is to have the drivers pass in their
>>> IRQ affinity masks, as Stanislav suggested, to avoid adding that
>>> call to the hot path.
>>>
>>> If not, then the IRQ from napi_struct can be used and the affinity
>>> mask can be generated on every napi poll. i40e/gve/iavf would need
>>> calls to netif_napi_set_irq to set the IRQ mapping, which seems to
>>> be straightforward.
>>
>> It's a bit sad to have the generic solution blocked.
>> cpu_rmap_update() is exported. Maybe we can call it from our notifier?
>> rmap lives in struct net_device
> 
> I agree on the sadness. I will take a look today.
> 
> I guess if we were being really ambitious, we'd try to move ARFS
> stuff into the core (as RSS was moved into the core).


Sorry for the late reply. Maybe we can modify affinity notifier infra to
support more than a single notifier per IRQ.
@Thomas, do you know why only a single notifier per IRQ is supported?