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

[Shrikanth Hegde]

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 <sri...@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 <sshe...@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 */