Re: [PATCH v5 5/6] powerpc/pseries: Add a helper for form1 cpu distance

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Jun 28, 2021 at 08:41:16PM +0530, Aneesh Kumar K.V wrote:
> This helper is only used with the dispatch trace log collection.
> A later patch will add Form2 affinity support and this change helps
> in keeping that simpler. Also add a comment explaining we don't expect
> the code to be called with FORM0
> 
> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>

What makes it a "relative_distance" rather than just a "distance"?

> ---
>  arch/powerpc/include/asm/topology.h   |  4 ++--
>  arch/powerpc/mm/numa.c                | 10 +++++++++-
>  arch/powerpc/platforms/pseries/lpar.c |  4 ++--
>  3 files changed, 13 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
> index e4db64c0e184..ac8b5ed79832 100644
> --- a/arch/powerpc/include/asm/topology.h
> +++ b/arch/powerpc/include/asm/topology.h
> @@ -36,7 +36,7 @@ static inline int pcibus_to_node(struct pci_bus *bus)
>  				 cpu_all_mask :				\
>  				 cpumask_of_node(pcibus_to_node(bus)))
>  
> -extern int cpu_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc);
> +int cpu_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc);
>  extern int __node_distance(int, int);
>  #define node_distance(a, b) __node_distance(a, b)
>  
> @@ -83,7 +83,7 @@ static inline void sysfs_remove_device_from_node(struct device *dev,
>  
>  static inline void update_numa_cpu_lookup_table(unsigned int cpu, int node) {}
>  
> -static inline int cpu_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
> +static inline int cpu_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
>  {
>  	return 0;
>  }
> diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
> index 7b142f79d600..c6293037a103 100644
> --- a/arch/powerpc/mm/numa.c
> +++ b/arch/powerpc/mm/numa.c
> @@ -166,7 +166,7 @@ static void unmap_cpu_from_node(unsigned long cpu)
>  }
>  #endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */
>  
> -int cpu_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
> +static int __cpu_form1_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
>  {
>  	int dist = 0;
>  
> @@ -182,6 +182,14 @@ int cpu_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
>  	return dist;
>  }
>  
> +int cpu_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
> +{
> +	/* We should not get called with FORM0 */
> +	VM_WARN_ON(affinity_form == FORM0_AFFINITY);
> +
> +	return __cpu_form1_relative_distance(cpu1_assoc, cpu2_assoc);
> +}
> +
>  /* must hold reference to node during call */
>  static const __be32 *of_get_associativity(struct device_node *dev)
>  {
> diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
> index dab356e3ff87..afefbdfe768d 100644
> --- a/arch/powerpc/platforms/pseries/lpar.c
> +++ b/arch/powerpc/platforms/pseries/lpar.c
> @@ -261,7 +261,7 @@ static int cpu_relative_dispatch_distance(int last_disp_cpu, int cur_disp_cpu)
>  	if (!last_disp_cpu_assoc || !cur_disp_cpu_assoc)
>  		return -EIO;
>  
> -	return cpu_distance(last_disp_cpu_assoc, cur_disp_cpu_assoc);
> +	return cpu_relative_distance(last_disp_cpu_assoc, cur_disp_cpu_assoc);
>  }
>  
>  static int cpu_home_node_dispatch_distance(int disp_cpu)
> @@ -281,7 +281,7 @@ static int cpu_home_node_dispatch_distance(int disp_cpu)
>  	if (!disp_cpu_assoc || !vcpu_assoc)
>  		return -EIO;
>  
> -	return cpu_distance(disp_cpu_assoc, vcpu_assoc);
> +	return cpu_relative_distance(disp_cpu_assoc, vcpu_assoc);
>  }
>  
>  static void update_vcpu_disp_stat(int disp_cpu)

-- 
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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