MINOR: cpu-topo: add NUMA node identification to CPUs on FreeBSD

With this patch we're also NUMA node IDs to each CPU when the info is
found. The code is highly inspired from the one in commit f5d48f8b3
("MEDIUM: cfgparse: numa detect topology on FreeBSD."), the difference
being that we're just setting the value in ha_cpu_topo[].

src/cpu_topo.c

@@ -417,7 +417,37 @@ int cpu_detect_topology(void)
 	return 1;
 }
 
-#else // __linux__
+#elif defined(__FreeBSD__)
+
+int cpu_detect_topology(void)
+{
+	struct hap_cpuset node_cpu_set;
+	int ndomains, domain, cpu;
+	size_t len = sizeof(ndomains);
+
+	/* Try to detect NUMA nodes */
+	if (sysctlbyname("vm.ndomains", &ndomains, &len, NULL, 0) == 0) {
+		BUG_ON(ndomains > MAXMEMDOM);
+
+		/* For each domain we'll reference the domain ID in the belonging
+		 * CPUs.
+		 */
+		for (domain = 0; domain < ndomains; domain++) {
+			ha_cpuset_zero(&node_cpu_set);
+
+			if (cpuset_getaffinity(CPU_LEVEL_WHICH, CPU_WHICH_DOMAIN, domain,
+					       sizeof(node_cpu_set.cpuset), &node_cpu_set.cpuset) == -1)
+				continue;
+
+			for (cpu = 0; cpu < cpu_topo_maxcpus; cpu++)
+				if (ha_cpuset_isset(&node_cpu_set, cpu))
+					ha_cpu_topo[cpu].no_id = domain;
+		}
+	}
+	return 1;
+}
+
+#else // !__linux__, !__FreeBSD__
 
 int cpu_detect_topology(void)
 {