netdev - Re: [PATCH net-next v6 0/5] net: napi: add CPU affinity to napi->config

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Message-ID: <Z5KmFNz7HDm9itoC@LQ3V64L9R2>
Date: Thu, 23 Jan 2025 12:27:00 -0800
From: Joe Damato <jdamato@...tly.com>
To: Ahmed Zaki <ahmed.zaki@...el.com>
Cc: netdev@...r.kernel.org, intel-wired-lan@...ts.osuosl.org,
	andrew+netdev@...n.ch, edumazet@...gle.com, kuba@...nel.org,
	horms@...nel.org, pabeni@...hat.com, davem@...emloft.net,
	michael.chan@...adcom.com, tariqt@...dia.com,
	anthony.l.nguyen@...el.com, przemyslaw.kitszel@...el.com,
	shayd@...dia.com, akpm@...ux-foundation.org, shayagr@...zon.com,
	kalesh-anakkur.purayil@...adcom.com
Subject: Re: [PATCH net-next v6 0/5] net: napi: add CPU affinity to
 napi->config

On Fri, Jan 17, 2025 at 05:33:30PM -0700, Ahmed Zaki wrote:
> Drivers usually need to re-apply the user-set IRQ affinity to their IRQs
> after reset. However, since there can be only one IRQ affinity notifier
> for each IRQ, registering IRQ notifiers conflicts with the ARFS rmap
> management in the core (which also registers separate IRQ affinity
> notifiers).   
> 
> Move the IRQ affinity management to the napi struct. This way we can have
> a unified IRQ notifier to re-apply the user-set affinity and also manage
> the ARFS rmaps. Patches 1 and 2 move the ARFS rmap management to CORE.
> Patch 3 adds the IRQ affinity mask to napi_config and re-applies the mask
> after reset. Patches 4-6 use the new API for bnxt, ice and idpf drivers.

Thanks for your work on this; I like the direction this is going and
I think providing this functionality via the core is very cool.

I am hoping that once this is merged, a change can be made that
builds on this work to eliminate the duplicated

  if (!cpumask_test_cpu(cpu, affinity_mask)) 

that a few drivers have in their napi poll functions with something
more generic for drivers which have persistent NAPI configs.