[RFC][PATCH 4/5] x86: Hard partition cpu topology masks on node boundaries

[Peter Zijlstra]

When using numa=fake= you can get weird topologies where LLCs can span
nodes and other such nonsense. Cure this by hard partitioning these
masks on node boundaries.

Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
---
 arch/x86/kernel/smpboot.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -337,6 +337,11 @@ void __cpuinit set_cpu_sibling_map(int c
 		for_each_cpu(i, cpu_sibling_setup_mask) {
 			struct cpuinfo_x86 *o = &cpu_data(i);
 
+#ifdef CONFIG_NUMA_EMU
+			if (cpu_to_node(cpu) != cpu_to_node(i))
+				continue;
+#endif
+
 			if (cpu_has(c, X86_FEATURE_TOPOEXT)) {
 				if (c->phys_proc_id == o->phys_proc_id &&
 				    per_cpu(cpu_llc_id, cpu) == per_cpu(cpu_llc_id, i) &&
@@ -360,11 +365,17 @@ void __cpuinit set_cpu_sibling_map(int c
 	}
 
 	for_each_cpu(i, cpu_sibling_setup_mask) {
+#ifdef CONFIG_NUMA_EMU
+		if (cpu_to_node(cpu) != cpu_to_node(i))
+			continue;
+#endif
+
 		if (per_cpu(cpu_llc_id, cpu) != BAD_APICID &&
 		    per_cpu(cpu_llc_id, cpu) == per_cpu(cpu_llc_id, i)) {
 			cpumask_set_cpu(i, cpu_llc_shared_mask(cpu));
 			cpumask_set_cpu(cpu, cpu_llc_shared_mask(i));
 		}
+
 		if (c->phys_proc_id == cpu_data(i).phys_proc_id) {
 			cpumask_set_cpu(i, cpu_core_mask(cpu));
 			cpumask_set_cpu(cpu, cpu_core_mask(i));


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