Re: [PATCH v3 2/3] powerpc/numa: Allow cpu_to_coregroup_id without PPC_SPLPAR

[Shrikanth Hegde <sshegde@linux.ibm.com>]

On 9/2/26 6:05 PM, Srikar Dronamraju wrote:
> Make cpu_to_coregroup_id() available outside PPC_SPLPAR so it can be
> used by platforms that do not rely on the SPLPAR-specific VPHN path.
> 
> Keep the existing fallback behavior by returning the core ID when
> coregroup information is unavailable.
> 
> Signed-off-by: Srikar Dronamraju <srikar@linux.ibm.com>
> ---
> Changelog from v2:
> - Handle comments from Ritesh (one hunk needed to be moved from patch 2 to
>    patch 3 to build correctly)
> 
> Changelog from v1:
> - Handle comments from Christophe Leroy; Remove extern key word in
>    declaration
> 
>   arch/powerpc/include/asm/topology.h | 15 +++++++--------
>   arch/powerpc/mm/numa.c              | 22 +++++++++++++++-------
>   2 files changed, 22 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
> index 44ec416fa489..02c3c9ab3ea9 100644
> --- a/arch/powerpc/include/asm/topology.h
> +++ b/arch/powerpc/include/asm/topology.h
> @@ -71,6 +71,7 @@ extern void map_cpu_to_node(int cpu, int node);
>   extern void unmap_cpu_from_node(unsigned long cpu);
>   #endif /* CONFIG_HOTPLUG_CPU */
>   
> +int cpu_to_coregroup_id(int cpu);

nit:

I prefer extern before declaration so that i can see it is defined
elsewhere.

Other than that, rest looks good to me.

Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>

>   #else
>   
>   static inline int early_cpu_to_node(int cpu) { return 0; }
> @@ -107,14 +108,6 @@ static inline void map_cpu_to_node(int cpu, int node) {}
>   static inline void unmap_cpu_from_node(unsigned long cpu) {}
>   #endif /* CONFIG_HOTPLUG_CPU */
>   #endif /* CONFIG_SMP */
> -
> -#endif /* CONFIG_NUMA */
> -
> -#if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
> -void find_and_update_cpu_nid(int cpu);
> -extern int cpu_to_coregroup_id(int cpu);
> -#else
> -static inline void find_and_update_cpu_nid(int cpu) {}
>   static inline int cpu_to_coregroup_id(int cpu)
>   {
>   #ifdef CONFIG_SMP
> @@ -124,6 +117,12 @@ static inline int cpu_to_coregroup_id(int cpu)
>   #endif
>   }
>   
> +#endif /* CONFIG_NUMA */
> +
> +#if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
> +void find_and_update_cpu_nid(int cpu);
> +#else
> +static inline void find_and_update_cpu_nid(int cpu) {}
>   #endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */
>   
>   #include <asm-generic/topology.h>
> diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
> index c44a80d8fc11..5f326b005a2a 100644
> --- a/arch/powerpc/mm/numa.c
> +++ b/arch/powerpc/mm/numa.c
> @@ -1428,6 +1428,21 @@ void find_and_update_cpu_nid(int cpu)
>   	pr_debug("%s:%d cpu %d nid %d\n", __func__, __LINE__, cpu, new_nid);
>   }
>   
> +static int topology_update_init(void)
> +{
> +	topology_inited = 1;
> +	return 0;
> +}
> +device_initcall(topology_update_init);
> +
> +#else
> +static long vphn_get_associativity(unsigned long cpu,
> +					__be32 *associativity)
> +{
> +	return -1;
> +}
> +#endif /* CONFIG_PPC_SPLPAR */
> +
>   int cpu_to_coregroup_id(int cpu)
>   {
>   	__be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
> @@ -1453,10 +1468,3 @@ int cpu_to_coregroup_id(int cpu)
>   	return cpu_to_core_id(cpu);
>   }
>   
> -static int topology_update_init(void)
> -{
> -	topology_inited = 1;
> -	return 0;
> -}
> -device_initcall(topology_update_init);
> -#endif /* CONFIG_PPC_SPLPAR */