Re: [Xen-devel] [PATCH 2 of 3] switch to dynamically allocated cpumask in domain_update_node_affinity()

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Tue, 2012-01-24 at 05:54 +0000, Juergen Gross wrote:
> # HG changeset patch
> # User Juergen Gross <juergen.gross@xxxxxxxxxxxxxx>
> # Date 1327384410 -3600
> # Node ID 08232960ff4bed750d26e5f1ff53972fee9e0130
> # Parent  99f98e501f226825fbf16f6210b4b7834dff5df1
> switch to dynamically allocated cpumask in
> domain_update_node_affinity()
> 
> cpumasks should rather be allocated dynamically.
> 
> Signed-off-by: juergen.gross@xxxxxxxxxxxxxx
> 
> diff -r 99f98e501f22 -r 08232960ff4b xen/common/domain.c
> --- a/xen/common/domain.c       Tue Jan 24 06:53:06 2012 +0100
> +++ b/xen/common/domain.c       Tue Jan 24 06:53:30 2012 +0100
> @@ -333,23 +333,27 @@ struct domain *domain_create(
>  
>  void domain_update_node_affinity(struct domain *d)
>  {
> -    cpumask_t cpumask;
> +    cpumask_var_t cpumask;
>      nodemask_t nodemask = NODE_MASK_NONE;
>      struct vcpu *v;
>      unsigned int node;
>  
> -    cpumask_clear(&cpumask);
> +    if ( !zalloc_cpumask_var(&cpumask) )
> +        return;

If this ends up always failing we will never set node_affinity to
anything at all. Granted that is already a pretty nasty situation to be
in but perhaps setting the affinity to NODE_MASK_ALL on failure is
slightly more robust?

> +
>      spin_lock(&d->node_affinity_lock);
>  
>      for_each_vcpu ( d, v )
> -        cpumask_or(&cpumask, &cpumask, v->cpu_affinity);
> +        cpumask_or(cpumask, cpumask, v->cpu_affinity);
>  
>      for_each_online_node ( node )
> -        if ( cpumask_intersects(&node_to_cpumask(node), &cpumask) )
> +        if ( cpumask_intersects(&node_to_cpumask(node), cpumask) )
>              node_set(node, nodemask);
>  
>      d->node_affinity = nodemask;
>      spin_unlock(&d->node_affinity_lock);
> +
> +    free_cpumask_var(cpumask);
>  }
>  
>   


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