Re: [Intel-wired-lan] [PATCH iwl-next v2] igc: Get rid of spurious interrupts

[Simon Horman <horms@kernel.org>]

On Fri, Jun 21, 2024 at 08:56:30AM +0200, Kurt Kanzenbach wrote:
> When running the igc with XDP/ZC in busy polling mode with deferral of hard
> interrupts, interrupts still happen from time to time. That is caused by
> the igc task watchdog which triggers Rx interrupts periodically.
> 
> That mechanism has been introduced to overcome skb/memory allocation
> failures [1]. So the Rx clean functions stop processing the Rx ring in case
> of such failure. The task watchdog triggers Rx interrupts periodically in
> the hope that memory became available in the mean time.
> 
> The current behavior is undesirable for real time applications, because the
> driver induced Rx interrupts trigger also the softirq processing. However,
> all real time packets should be processed by the application which uses the
> busy polling method.
> 
> Therefore, only trigger the Rx interrupts in case of real allocation
> failures. Introduce a new flag for signaling that condition.
> 
> [1] - https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/?id=3be507547e6177e5c808544bd6a2efa2c7f1d436
> 
> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
> Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
> Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>

Reviewed-by: Simon Horman <horms@kernel.org>