Re: [PATCH 7/7] x86/resctrl: Determine if Sub-NUMA Cluster is enabled and initialize.

[Peter Newman]

Hi Tony,

On Thu, Jan 26, 2023 at 7:42 PM Tony Luck <tony.luck@xxxxxxxxx> wrote:
> +static __init int find_snc_ways(void)
> +{
> +       unsigned long *node_caches;
> +       int cpu, node, ret;
> +
> +       node_caches = kcalloc(BITS_TO_LONGS(nr_node_ids), sizeof(*node_caches), GFP_KERNEL);
> +       if (!node_caches)
> +               return 1;
> +
> +       cpus_read_lock();
> +       for_each_node(node) {

Someone tried this patch on a machine with a CPU-less node...

We need to check for this:

+               if (cpumask_empty(cpumask_of_node(node)))
+                       continue;

> +               cpu = cpumask_first(cpumask_of_node(node));
> +               set_bit(get_cpu_cacheinfo_id(cpu, 3), node_caches);
> +       }
> +       cpus_read_unlock();

Thanks!
-Peter