perf svghelper: Replace MAX_NR_CPUS with perf_env::nr_cpus_online

'nr_cpus', the number of CPUs online during a record session bound by
MAX_NR_CPUS, can be used as a dynamic alternative for MAX_NR_CPUS in
svg_build_topology_map().

The value of nr_cpus can be passed into str_to_bitmap(),
scan_core_topology(), and svg_build_topology_map() to replace
MAX_NR_CPUS as well.
Signed-off-by: Kyle Meyer <kyle.meyer@hpe.com>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <russ.anderson@hpe.com>
Link: http://lore.kernel.org/lkml/20190827214352.94272-3-meyerk@stormcage.eag.rdlabs.hpecorp.netSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/svghelper.c

@@ -697,7 +697,8 @@ struct topology {
 	int sib_thr_nr;
 };
 
-static void scan_thread_topology(int *map, struct topology *t, int cpu, int *pos)
+static void scan_thread_topology(int *map, struct topology *t, int cpu,
+				 int *pos, int nr_cpus)
 {
 	int i;
 	int thr;
@@ -706,28 +707,24 @@ static void scan_thread_topology(int *map, struct topology *t, int cpu, int *pos
 		if (!test_bit(cpu, cpumask_bits(&t->sib_thr[i])))
 			continue;
 
-		for_each_set_bit(thr,
-				 cpumask_bits(&t->sib_thr[i]),
-				 MAX_NR_CPUS)
+		for_each_set_bit(thr, cpumask_bits(&t->sib_thr[i]), nr_cpus)
 			if (map[thr] == -1)
 				map[thr] = (*pos)++;
 	}
 }
 
-static void scan_core_topology(int *map, struct topology *t)
+static void scan_core_topology(int *map, struct topology *t, int nr_cpus)
 {
 	int pos = 0;
 	int i;
 	int cpu;
 
 	for (i = 0; i < t->sib_core_nr; i++)
-		for_each_set_bit(cpu,
-				 cpumask_bits(&t->sib_core[i]),
-				 MAX_NR_CPUS)
-			scan_thread_topology(map, t, cpu, &pos);
+		for_each_set_bit(cpu, cpumask_bits(&t->sib_core[i]), nr_cpus)
+			scan_thread_topology(map, t, cpu, &pos, nr_cpus);
 }
 
-static int str_to_bitmap(char *s, cpumask_t *b)
+static int str_to_bitmap(char *s, cpumask_t *b, int nr_cpus)
 {
 	int i;
 	int ret = 0;
@@ -740,7 +737,7 @@ static int str_to_bitmap(char *s, cpumask_t *b)
 
 	for (i = 0; i < m->nr; i++) {
 		c = m->map[i];
-		if (c >= MAX_NR_CPUS) {
+		if (c >= nr_cpus) {
 			ret = -1;
 			break;
 		}
@@ -755,10 +752,12 @@ static int str_to_bitmap(char *s, cpumask_t *b)
 
 int svg_build_topology_map(struct perf_env *env)
 {
-	int i;
+	int i, nr_cpus;
 	struct topology t;
 	char *sib_core, *sib_thr;
 
+	nr_cpus = min(env->nr_cpus_online, MAX_NR_CPUS);
+
 	t.sib_core_nr = env->nr_sibling_cores;
 	t.sib_thr_nr = env->nr_sibling_threads;
 	t.sib_core = calloc(env->nr_sibling_cores, sizeof(cpumask_t));
@@ -773,7 +772,7 @@ int svg_build_topology_map(struct perf_env *env)
 	}
 
 	for (i = 0; i < env->nr_sibling_cores; i++) {
-		if (str_to_bitmap(sib_core, &t.sib_core[i])) {
+		if (str_to_bitmap(sib_core, &t.sib_core[i], nr_cpus)) {
 			fprintf(stderr, "topology: can't parse siblings map\n");
 			goto exit;
 		}
@@ -782,7 +781,7 @@ int svg_build_topology_map(struct perf_env *env)
 	}
 
 	for (i = 0; i < env->nr_sibling_threads; i++) {
-		if (str_to_bitmap(sib_thr, &t.sib_thr[i])) {
+		if (str_to_bitmap(sib_thr, &t.sib_thr[i], nr_cpus)) {
 			fprintf(stderr, "topology: can't parse siblings map\n");
 			goto exit;
 		}
@@ -790,16 +789,16 @@ int svg_build_topology_map(struct perf_env *env)
 		sib_thr += strlen(sib_thr) + 1;
 	}
 
-	topology_map = malloc(sizeof(int) * MAX_NR_CPUS);
+	topology_map = malloc(sizeof(int) * nr_cpus);
 	if (!topology_map) {
 		fprintf(stderr, "topology: no memory\n");
 		goto exit;
 	}
 
-	for (i = 0; i < MAX_NR_CPUS; i++)
+	for (i = 0; i < nr_cpus; i++)
 		topology_map[i] = -1;
 
-	scan_core_topology(topology_map, &t);
+	scan_core_topology(topology_map, &t, nr_cpus);
 
 	return 0;