Re: [PATCH 11/14] irq: add support for allocating (and affinitizing) sets of IRQs

[Ming Lei]

On Mon, Oct 29, 2018 at 10:37:35AM -0600, Jens Axboe wrote:
> A driver may have a need to allocate multiple sets of MSI/MSI-X
> interrupts, and have them appropriately affinitized. Add support for
> defining a number of sets in the irq_affinity structure, of varying
> sizes, and get each set affinitized correctly across the machine.
> 
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Reviewed-by: Hannes Reinecke <hare@xxxxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> ---
>  include/linux/interrupt.h |  4 ++++
>  kernel/irq/affinity.c     | 40 ++++++++++++++++++++++++++++++---------
>  2 files changed, 35 insertions(+), 9 deletions(-)
> 
> diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
> index 1d6711c28271..ca397ff40836 100644
> --- a/include/linux/interrupt.h
> +++ b/include/linux/interrupt.h
> @@ -247,10 +247,14 @@ struct irq_affinity_notify {
>   *			the MSI(-X) vector space
>   * @post_vectors:	Don't apply affinity to @post_vectors at end of
>   *			the MSI(-X) vector space
> + * @nr_sets:		Length of passed in *sets array
> + * @sets:		Number of affinitized sets
>   */
>  struct irq_affinity {
>  	int	pre_vectors;
>  	int	post_vectors;
> +	int	nr_sets;
> +	int	*sets;
>  };
>  
>  #if defined(CONFIG_SMP)
> diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
> index f4f29b9d90ee..2046a0f0f0f1 100644
> --- a/kernel/irq/affinity.c
> +++ b/kernel/irq/affinity.c
> @@ -180,6 +180,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
>  	int curvec, usedvecs;
>  	cpumask_var_t nmsk, npresmsk, *node_to_cpumask;
>  	struct cpumask *masks = NULL;
> +	int i, nr_sets;
>  
>  	/*
>  	 * If there aren't any vectors left after applying the pre/post
> @@ -210,10 +211,23 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
>  	get_online_cpus();
>  	build_node_to_cpumask(node_to_cpumask);
>  
> -	/* Spread on present CPUs starting from affd->pre_vectors */
> -	usedvecs = irq_build_affinity_masks(affd, curvec, affvecs,
> -					    node_to_cpumask, cpu_present_mask,
> -					    nmsk, masks);
> +	/*
> +	 * Spread on present CPUs starting from affd->pre_vectors. If we
> +	 * have multiple sets, build each sets affinity mask separately.
> +	 */
> +	nr_sets = affd->nr_sets;
> +	if (!nr_sets)
> +		nr_sets = 1;
> +
> +	for (i = 0, usedvecs = 0; i < nr_sets; i++) {
> +		int this_vecs = affd->sets ? affd->sets[i] : affvecs;
> +		int nr;
> +
> +		nr = irq_build_affinity_masks(affd, curvec, this_vecs,
> +					      node_to_cpumask, cpu_present_mask,
> +					      nmsk, masks + usedvecs);
> +		usedvecs += nr;
> +	}
>  
>  	/*
>  	 * Spread on non present CPUs starting from the next vector to be
> @@ -258,13 +272,21 @@ int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity
>  {
>  	int resv = affd->pre_vectors + affd->post_vectors;
>  	int vecs = maxvec - resv;
> -	int ret;
> +	int set_vecs;
>  
>  	if (resv > minvec)
>  		return 0;
>  
> -	get_online_cpus();
> -	ret = min_t(int, cpumask_weight(cpu_possible_mask), vecs) + resv;
> -	put_online_cpus();
> -	return ret;
> +	if (affd->nr_sets) {
> +		int i;
> +
> +		for (i = 0, set_vecs = 0;  i < affd->nr_sets; i++)
> +			set_vecs += affd->sets[i];
> +	} else {
> +		get_online_cpus();
> +		set_vecs = cpumask_weight(cpu_possible_mask);
> +		put_online_cpus();
> +	}
> +
> +	return resv + min(set_vecs, vecs);
>  }
> -- 
> 2.17.1
> 

Looks fine:

Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>

-- 
Ming