Subject: Re: [next-queue 1/3] i40e: Store the irq number in i40e_q_vector

From: Maciej Fijalkowski <[email-masked]>
Date: Wed, 5 Oct 2022 12:29:24 +0200

On Wed, Oct 05, 2022 at 01:31:41AM -0700, Joe Damato wrote:
> Make it easy to figure out the IRQ number for a particular i40e_q_vector by
> storing the assigned IRQ in the structure itself.
> 
> Signed-off-by: Joe Damato <[email-masked]>
> ---
>  drivers/net/ethernet/intel/i40e/i40e.h      | 1 +
>  drivers/net/ethernet/intel/i40e/i40e_main.c | 1 +
>  2 files changed, 2 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h
> index 9926c4e..8e1f395 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e.h
> +++ b/drivers/net/ethernet/intel/i40e/i40e.h
> @@ -992,6 +992,7 @@ struct i40e_q_vector {
>  	struct rcu_head rcu;	/* to avoid race with update stats on free */
>  	char name[I40E_INT_NAME_STR_LEN];
>  	bool arm_wb_state;
> +	int irq_num;		/* IRQ assigned to this q_vector */

This struct looks like a mess in terms of members order. Can you check
with pahole how your patch affects the layout of it? Maybe while at it you
could pack it in a better way?

>  } ____cacheline_internodealigned_in_smp;
>  
>  /* lan device */
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
> index 6b7535a..6efe130 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_main.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
> @@ -4123,6 +4123,7 @@ static int i40e_vsi_request_irq_msix(struct i40e_vsi *vsi, char *basename)
>  		}
>  
>  		/* register for affinity change notifications */
> +		q_vector->irq_num = irq_num;
>  		q_vector->affinity_notify.notify = i40e_irq_affinity_notify;
>  		q_vector->affinity_notify.release = i40e_irq_affinity_release;
>  		irq_set_affinity_notifier(irq_num, &q_vector->affinity_notify);
> -- 
> 2.7.4
>