Re: [Qemu-devel] [PATCH v4 1/1] numa: Print warning if no node is assigned to a CPU

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Feb 24, 2015 at 03:57:23PM -0300, Eduardo Habkost wrote:
> Instead of silently assigning CPU to node 0 when it is omitted from the
> command-line, check if all CPUs up to max_cpus are present in the NUMA
> configuration.

Could you please describe the problematic configuration
in more detail in commit log?
Also, how does this interact with cpu hotplug?

> 
> I am making this a warning and not a fatal error, to allow management
> software to be updated if necessary.
>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
> v1 -> v2: (no changes)
> 
> v2 -> v3:
>  * Use enumerate_cpus() and error_report() for error message
>  * Simplify logic using bitmap_full()
> 
> v3 -> v4:
>  * Clarify error message, mention that all CPUs up to
>    maxcpus need to be described in NUMA config
> ---
>  numa.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/numa.c b/numa.c
> index 9a3fc15..d8021b9 100644
> --- a/numa.c
> +++ b/numa.c
> @@ -201,6 +201,16 @@ static void validate_numa_cpus(void)
>          bitmap_or(seen_cpus, seen_cpus,
>                    numa_info[i].node_cpu, MAX_CPUMASK_BITS);
>      }
> +
> +    if (!bitmap_full(seen_cpus, max_cpus)) {
> +        char *msg;
> +        bitmap_complement(seen_cpus, seen_cpus, max_cpus);
> +        msg = enumerate_cpus(seen_cpus, max_cpus);
> +        error_report("warning: CPU(s) not present in any NUMA nodes: %s", msg);
> +        error_report("warning: All CPU(s) up to maxcpus should be described "
> +                     "in NUMA config");

What happens with e.g. windows guests when this warning is emitted?
do they blue-screen?

> +        g_free(msg);
> +    }
>  }
>  
>  void parse_numa_opts(void)
> -- 
> 2.1.0