Re: [PATCH 02/10] numa: introduce MachineClass::forbid_asymmetrical_numa

[David Gibson]

On Fri, Aug 14, 2020 at 05:54:16PM -0300, Daniel Henrique Barboza wrote:
> The pSeries machine does not support asymmetrical NUMA
> configurations.

This seems a bit oddly specific to have as a global machine class
property.

Would it make more sense for machines with specific NUMA constraints
to just verify those during their initialization?
> 
> CC: Eduardo Habkost <ehabkost@redhat.com>
> CC: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
> ---
>  hw/core/numa.c      | 7 +++++++
>  hw/ppc/spapr.c      | 1 +
>  include/hw/boards.h | 1 +
>  3 files changed, 9 insertions(+)
> 
> diff --git a/hw/core/numa.c b/hw/core/numa.c
> index d1a94a14f8..1e81233c1d 100644
> --- a/hw/core/numa.c
> +++ b/hw/core/numa.c
> @@ -547,6 +547,7 @@ static int parse_numa(void *opaque, QemuOpts *opts, Error 
> **errp)
>   */
>  static void validate_numa_distance(MachineState *ms)
>  {
> +    MachineClass *mc = MACHINE_GET_CLASS(ms);
>      int src, dst;
>      bool is_asymmetrical = false;
>      int nb_numa_nodes = ms->numa_state->num_nodes;
> @@ -575,6 +576,12 @@ static void validate_numa_distance(MachineState *ms)
>      }
>  
>      if (is_asymmetrical) {
> +        if (mc->forbid_asymmetrical_numa) {
> +            error_report("This machine type does not support "
> +                         "asymmetrical numa distances.");
> +            exit(EXIT_FAILURE);
> +        }
> +
>          for (src = 0; src < nb_numa_nodes; src++) {
>              for (dst = 0; dst < nb_numa_nodes; dst++) {
>                  if (src != dst && numa_info[src].distance[dst] == 0) {
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index dd2fa4826b..3b16edaf4c 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -4512,6 +4512,7 @@ static void spapr_machine_class_init(ObjectClass *oc, 
> void *data)
>       */
>      mc->numa_mem_align_shift = 28;
>      mc->auto_enable_numa = true;
> +    mc->forbid_asymmetrical_numa = true;
>  
>      smc->default_caps.caps[SPAPR_CAP_HTM] = SPAPR_CAP_OFF;
>      smc->default_caps.caps[SPAPR_CAP_VSX] = SPAPR_CAP_ON;
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index bc5b82ad20..dc6cdd1c53 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -215,6 +215,7 @@ struct MachineClass {
>      bool nvdimm_supported;
>      bool numa_mem_supported;
>      bool auto_enable_numa;
> +    bool forbid_asymmetrical_numa;
>      const char *default_ram_id;
>  
>      HotplugHandler *(*get_hotplug_handler)(MachineState *machine,

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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