* Shrikanth Hegde <[email protected]> [2026-09-04 15:34:50]: > On 9/2/26 6:05 PM, Srikar Dronamraju wrote: > > Coregroup support on powerpc has so far been limited to PowerVM LPARs. > > However, PowerNV can also support coregroups when firmware exposes the > > required coregroup information through the associativity hierarchy. > > > > Existing firmware does expose this info already? > > > Detect coregroup support by checking whether primary_domain_index is the > > penultimate domain in the CPU node's ibm,associativity property. On > > PowerNV, a non-penultimate primary_domain_index indicates that firmware > > provides an additional level for coregroup information. > > > > This keeps the logic compatible with PowerVM systems, where > > primary_domain_index is likewise not the penultimate associativity > > domain. > > > > Could you please put the ibm,associativity on this powernv? as well > PowerVM's so that one understands it better? > > > Signed-off-by: Srikar Dronamraju <[email protected]> > > --- > > 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: > > https://lkml.kernel.org/r/[email protected] > > - Handle comments from Christophe Leroy; make code more flat > > > > arch/powerpc/mm/numa.c | 58 ++++++++++++++++++++++++++++++++++-------- > > 1 file changed, 48 insertions(+), 10 deletions(-) > > > > diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c > > index 5f326b005a2a..e97b624203ea 100644 > > --- a/arch/powerpc/mm/numa.c > > +++ b/arch/powerpc/mm/numa.c > > @@ -889,12 +889,32 @@ static int __init numa_setup_drmem_lmb(struct > > drmem_lmb *lmb, > > return 0; > > } > > +/* > > + * If hierarchy extends beyond primary_domain_index + 1, then next > > + * level corresponds to coregroup. > > + */ > > +static int detect_and_enable_coregroup(const __be32 *associativity, int > > index) > > +{ > > + if (!associativity || index == -1) > > + goto out; > > + > > + index = of_read_number(associativity, 1); > > + > > + if (index > primary_domain_index + 1) { > > + coregroup_enabled = 1; > > + return index; > > + } > > +out: > > + coregroup_enabled = 0; > > + return -1; > > +} > > + > > static int __init parse_numa_properties(void) > > { > > struct device_node *memory, *pci; > > - int default_nid = 0; > > - unsigned long i; > > + int default_nid = 0, index = 0; > > const __be32 *associativity; > > + unsigned long i; > > if (numa_enabled == 0) { > > pr_warn("disabled by user\n"); > > @@ -927,7 +947,6 @@ static int __init parse_numa_properties(void) > > */ > > for_each_present_cpu(i) { > > __be32 vphn_assoc[VPHN_ASSOC_BUFSIZE]; > > - struct device_node *cpu; > > int nid = NUMA_NO_NODE; > > memset(vphn_assoc, 0, VPHN_ASSOC_BUFSIZE * sizeof(__be32)); > > @@ -935,7 +954,9 @@ static int __init parse_numa_properties(void) > > if (__vphn_get_associativity(i, vphn_assoc) == 0) { > > nid = associativity_to_nid(vphn_assoc); > > initialize_form1_numa_distance(vphn_assoc); > > + index = detect_and_enable_coregroup(vphn_assoc, index); > > nit: I don't see return value being used.
index is getting used within the loop. Do note, we are passing index as a parameter to detect_and_enable_coregroup(). For example, index is set to -1, in the first iteration, then in the next iterations, detect_and_enable_coregroup will not retry. So the return value gets used. > > Other than that, rest looks good to me. > Reviewed-by: Shrikanth Hegde <[email protected]> > > > } else { -- Thanks and Regards Srikar Dronamraju
