Re: [PATCH net-next V2 1/2] net: Utility function to get affinity_hint by policy

[Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>]

Hello.

On 05-03-2014 14:09, Amir Vadai wrote:

> This function sets the affinity_mask according to a numa aware policy.
> affinity_mask could be used as an affinity hint for the IRQ related to
> this rx queue.
> Current policy is to spread rx queues accross cores - local cores first.
> It could be extended in the future.

> CC: Prarit Bhargava <prarit@redhat.com>
> CC: Govindarajulu Varadarajan <gvaradar@cisco.com>
> Signed-off-by: Amir Vadai <amirv@mellanox.com>
[...]

> diff --git a/net/core/dev.c b/net/core/dev.c
> index b1b0c8d..0b22f67 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -2116,6 +2116,62 @@ int netif_set_real_num_rx_queues(struct net_device *dev, unsigned int rxq)
>   EXPORT_SYMBOL(netif_set_real_num_rx_queues);
>   #endif
>
> +/* netif_set_rx_queue_affinity_hint - set affinity hint of rx queue

    This should be a comment in the kernel-doc style, starting with /** on a 
line of its own.

> + * @rxq: index of rx queue
> + * @numa_node: prefered numa_node
> + * @affinity_mask: the relevant cpu bit is set according to the policy
> + *
> + * This function sets the affinity_mask according to a numa aware policy.
> + * affinity_mask coulbe used as an affinity hint for the IRQ related to this
> + * rx queue.
> + * The policy is to spread rx queues accross cores - local cores first.
> + *
> + * Returns 0 on success, or a negative error code.
> + */
> +int netif_set_rx_queue_affinity_hint(int rxq, int numa_node,
> +				     cpumask_var_t affinity_mask)
> +{
> +	const struct cpumask *p_numa_cores_mask;
> +	cpumask_var_t non_numa_cores_mask = NULL;
> +	int affinity_cpu;
> +	int ret = 0;
> +
> +	rxq = rxq % num_online_cpus();

    Why not:

	rxq %= num_online_cpus();

WBR, Sergei