[tip:,x86/core] x86, sched: Treat Intel SNC topology as default, COD as exception

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 02813a7..147b2f3 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -458,29 +458,52 @@  static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
 	return false;
 }
 
+static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
+{
+	if (c->phys_proc_id == o->phys_proc_id &&
+	    c->cpu_die_id == o->cpu_die_id)
+		return true;
+	return false;
+}
+
 /*
- * Define snc_cpu[] for SNC (Sub-NUMA Cluster) CPUs.
+ * Unlike the other levels, we do not enforce keeping a
+ * multicore group inside a NUMA node.  If this happens, we will
+ * discard the MC level of the topology later.
+ */
+static bool match_pkg(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
+{
+	if (c->phys_proc_id == o->phys_proc_id)
+		return true;
+	return false;
+}
+
+/*
+ * Define intel_cod_cpu[] for Intel COD (Cluster-on-Die) CPUs.
  *
- * These are Intel CPUs that enumerate an LLC that is shared by
- * multiple NUMA nodes. The LLC on these systems is shared for
- * off-package data access but private to the NUMA node (half
- * of the package) for on-package access.
+ * Any Intel CPU that has multiple nodes per package and does not
+ * match intel_cod_cpu[] has the SNC (Sub-NUMA Cluster) topology.
  *
- * CPUID (the source of the information about the LLC) can only
- * enumerate the cache as being shared *or* unshared, but not
- * this particular configuration. The CPU in this case enumerates
- * the cache to be shared across the entire package (spanning both
- * NUMA nodes).
+ * When in SNC mode, these CPUs enumerate an LLC that is shared
+ * by multiple NUMA nodes. The LLC is shared for off-package data
+ * access but private to the NUMA node (half of the package) for
+ * on-package access. CPUID (the source of the information about
+ * the LLC) can only enumerate the cache as shared or unshared,
+ * but not this particular configuration.
  */
 
-static const struct x86_cpu_id snc_cpu[] = {
-	X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE_X, NULL),
+static const struct x86_cpu_id intel_cod_cpu[] = {
+	X86_MATCH_INTEL_FAM6_MODEL(HASWELL_X, 0),	/* COD */
+	X86_MATCH_INTEL_FAM6_MODEL(BROADWELL_X, 0),	/* COD */
+	X86_MATCH_INTEL_FAM6_MODEL(ANY, 1),		/* SNC */
 	{}
 };
 
 static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
 {
+	const struct x86_cpu_id *id = x86_match_cpu(intel_cod_cpu);
 	int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
+	bool intel_snc = id && id->driver_data;
 
 	/* Do not match if we do not have a valid APICID for cpu: */
 	if (per_cpu(cpu_llc_id, cpu1) == BAD_APICID)
@@ -495,32 +518,12 @@  static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
 	 * means 'c' does not share the LLC of 'o'. This will be
 	 * reflected to userspace.
 	 */
-	if (!topology_same_node(c, o) && x86_match_cpu(snc_cpu))
+	if (match_pkg(c, o) && !topology_same_node(c, o) && intel_snc)
 		return false;
 
 	return topology_sane(c, o, "llc");
 }
 
-/*
- * Unlike the other levels, we do not enforce keeping a
- * multicore group inside a NUMA node.  If this happens, we will
- * discard the MC level of the topology later.
- */
-static bool match_pkg(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
-{
-	if (c->phys_proc_id == o->phys_proc_id)
-		return true;
-	return false;
-}
-
-static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
-{
-	if ((c->phys_proc_id == o->phys_proc_id) &&
-		(c->cpu_die_id == o->cpu_die_id))
-		return true;
-	return false;
-}
-
 
 #if defined(CONFIG_SCHED_SMT) || defined(CONFIG_SCHED_MC)
 static inline int x86_sched_itmt_flags(void)
@@ -592,14 +595,23 @@  void set_cpu_sibling_map(int cpu)
 	for_each_cpu(i, cpu_sibling_setup_mask) {
 		o = &cpu_data(i);
 
+		if (match_pkg(c, o) && !topology_same_node(c, o))
+			x86_has_numa_in_package = true;
+
 		if ((i == cpu) || (has_smt && match_smt(c, o)))
 			link_mask(topology_sibling_cpumask, cpu, i);
 
 		if ((i == cpu) || (has_mp && match_llc(c, o)))
 			link_mask(cpu_llc_shared_mask, cpu, i);
 
+		if ((i == cpu) || (has_mp && match_die(c, o)))
+			link_mask(topology_die_cpumask, cpu, i);
 	}
 
+	threads = cpumask_weight(topology_sibling_cpumask(cpu));
+	if (threads > __max_smt_threads)
+		__max_smt_threads = threads;
+
 	/*
 	 * This needs a separate iteration over the cpus because we rely on all
 	 * topology_sibling_cpumask links to be set-up.
@@ -613,8 +625,7 @@  void set_cpu_sibling_map(int cpu)
 			/*
 			 *  Does this new cpu bringup a new core?
 			 */
-			if (cpumask_weight(
-			    topology_sibling_cpumask(cpu)) == 1) {
+			if (threads == 1) {
 				/*
 				 * for each core in package, increment
 				 * the booted_cores for this new cpu
@@ -631,16 +642,7 @@  void set_cpu_sibling_map(int cpu)
 			} else if (i != cpu && !c->booted_cores)
 				c->booted_cores = cpu_data(i).booted_cores;
 		}
-		if (match_pkg(c, o) && !topology_same_node(c, o))
-			x86_has_numa_in_package = true;
-
-		if ((i == cpu) || (has_mp && match_die(c, o)))
-			link_mask(topology_die_cpumask, cpu, i);
 	}
-
-	threads = cpumask_weight(topology_sibling_cpumask(cpu));
-	if (threads > __max_smt_threads)
-		__max_smt_threads = threads;
 }
 
 /* maps the cpu to the sched domain representing multi-core */