Re: [Qemu-devel] [PATCH v2 05/24] numa: move source of default CPUs to NUMA node mapping into boards

[Eduardo Habkost <ehabkost@redhat.com>]

On Wed, May 03, 2017 at 02:56:59PM +0200, Igor Mammedov wrote:
[...]
> diff --git a/numa.c b/numa.c
> index 6fc2393..ab1661d 100644
> --- a/numa.c
> +++ b/numa.c
> @@ -294,9 +294,10 @@ static void validate_numa_cpus(void)
>      g_free(seen_cpus);
>  }
>  
> -void parse_numa_opts(MachineClass *mc)
> +void parse_numa_opts(MachineState *ms)
>  {
>      int i;
> +    MachineClass *mc = MACHINE_GET_CLASS(ms);
>  
>      for (i = 0; i < MAX_NODES; i++) {
>          numa_info[i].node_cpu = bitmap_new(max_cpus);
> @@ -378,14 +379,16 @@ void parse_numa_opts(MachineClass *mc)


Expanding diff context:

>          /* Historically VCPUs were assigned in round-robin order to NUMA
>           * nodes. However it causes issues with guest not handling it nice
>           * in case where cores/threads from a multicore CPU appear on
>           * different nodes. So allow boards to override default distribution
>           * rule grouping VCPUs by socket so that VCPUs from the same socket
>           * would be on the same node.
>           */

The above comment looks obsolete, as we are removing the code inside
parse_numa_opts() that deals with grouping VCPUs by socket.

(Can be fixed by a follow-up patch, if necessary.)

> +        if (!mc->cpu_index_to_instance_props) {
> +            error_report("default CPUs to NUMA node mapping isn't supported");
> +            exit(1);
> +        }
>          if (i == nb_numa_nodes) {
>              for (i = 0; i < max_cpus; i++) {
> -                unsigned node_id = i % nb_numa_nodes;
> -                if (mc->cpu_index_to_socket_id) {
> -                    node_id = mc->cpu_index_to_socket_id(i) % nb_numa_nodes;
> -                }
> +                CpuInstanceProperties props;
> +                props = mc->cpu_index_to_instance_props(ms, i);
>  
> -                set_bit(i, numa_info[node_id].node_cpu);
> +                set_bit(i, numa_info[props.node_id].node_cpu);
>              }
>          }
>  
[...]

-- 
Eduardo