Re: [PATCH v6 3/9] xen: derive NUMA node affinity from hard and soft CPU affinity

["Jan Beulich" <JBeulich@suse.com>]

>>> On 28.05.14 at 02:42, <dario.faggioli@citrix.com> wrote:
> @@ -425,31 +425,48 @@ void domain_update_node_affinity(struct domain *d)
>  
>      spin_lock(&d->node_affinity_lock);
>  
> -    for_each_vcpu ( d, v )
> -    {
> -        cpumask_and(online_affinity, v->cpu_hard_affinity, online);
> -        cpumask_or(cpumask, cpumask, online_affinity);
> -    }
> -
>      /*
> -     * If d->auto_node_affinity is true, the domain's node-affinity mask
> -     * (d->node_affinity) is automaically computed from all the domain's
> -     * vcpus' vcpu-affinity masks (the union of which we have just built
> -     * above in cpumask). OTOH, if d->auto_node_affinity is false, we
> -     * must leave the node-affinity of the domain alone.
> +     * If d->auto_node_affinity is true, let's compute the domain's
> +     * node-affinity and update d->node_affinity accordingly. if false,
> +     * just leave d->auto_node_affinity alone.
>       */
>      if ( d->auto_node_affinity )
>      {
> +        /*
> +         * We want the narrowest possible set of pcpus (to get the narowest
> +         * possible set of nodes). What we need is the cpumask of where the
> +         * domain can run (the union of the hard affinity of all its vcpus),
> +         * and the full mask of where it would prefer to run (the union of
> +         * the soft affinity of all its various vcpus). Let's build them.
> +         */
> +        for_each_vcpu ( d, v )
> +        {
> +            cpumask_or(dom_cpumask, dom_cpumask, v->cpu_hard_affinity);
> +            cpumask_or(dom_cpumask_soft, dom_cpumask_soft,
> +                       v->cpu_soft_affinity);
> +        }
> +        /* Filter out non-online cpus */
> +        cpumask_and(dom_cpumask, dom_cpumask, online);
> +        ASSERT(!cpumask_empty(dom_cpumask));
> +        /* And compute the intersection between hard, online and soft */
> +        cpumask_and(dom_cpumask_soft, dom_cpumask_soft, dom_cpumask);
> +
> +        /*
> +         * If not empty, the intersection of hard, soft and online is the
> +         * narrowest set we want. If empty, we fall back to hard&online.
> +         */
> +        dom_affinity = cpumask_empty(dom_cpumask_soft) ?
> +                           dom_cpumask : dom_cpumask_soft;
> +
>          nodes_clear(d->node_affinity);
> -        for_each_online_node ( node )
> -            if ( cpumask_intersects(&node_to_cpumask(node), cpumask) )
> -                node_set(node, d->node_affinity);
> +        for_each_cpu( cpu, dom_affinity )

There's a minor coding style issue here (missing blank before opening
parenthesis), but nonetheless
Acked-by: Jan Beulich <jbeulich@suse.com>