RE: [PATCH] genirq/affinity: Spread IRQs to all available NUMA nodes

[Michael Kelley]

From: Long Li <longli@xxxxxxxxxxxxx>  Sent: Thursday, November 1, 2018 4:52 PM
> 
> --- a/kernel/irq/affinity.c
> +++ b/kernel/irq/affinity.c
> @@ -117,12 +117,13 @@ static int irq_build_affinity_masks(const struct irq_affinity *affd,
>  	 */
>  	if (numvecs <= nodes) {
>  		for_each_node_mask(n, nodemsk) {
> -			cpumask_copy(masks + curvec, node_to_cpumask[n]);
> -			if (++done == numvecs)
> -				break;
> +			cpumask_or(masks + curvec, masks + curvec, node_to_cpumask[n]);
> +			done++;
>  			if (++curvec == last_affv)
>  				curvec = affd->pre_vectors;
>  		}

When the above for loop is exited, 'done' will always be equal to 'nodes' since
there are no early exits from the loop.  Hence there's no need to be
incrementing 'done' in the loop. 

> +		if (done > numvecs)
> +			done = numvecs;

And if 'done' would always be equal to 'nodes', there is no need for the test.
Just always set 'done' to 'numvecs'.

>  		goto out;
>  	}
> 
> --
> 2.14.1