4 files changed, 53 insertions, 2 deletions

diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c
index 4adcd7920d..cae799ad44 100644
--- a/tools/lib/perf/cpumap.c
+++ b/tools/lib/perf/cpumap.c
@@ -18,9 +18,13 @@ void perf_cpu_map__set_nr(struct perf_cpu_map *map, int nr_cpus)
 
 struct perf_cpu_map *perf_cpu_map__alloc(int nr_cpus)
 {
-	RC_STRUCT(perf_cpu_map) *cpus = malloc(sizeof(*cpus) + sizeof(struct perf_cpu) * nr_cpus);
+	RC_STRUCT(perf_cpu_map) *cpus;
 	struct perf_cpu_map *result;
 
+	if (nr_cpus == 0)
+		return NULL;
+
+	cpus = malloc(sizeof(*cpus) + sizeof(struct perf_cpu) * nr_cpus);
 	if (ADD_RC_CHK(result, cpus)) {
 		cpus->nr = nr_cpus;
 		refcount_set(&cpus->refcnt, 1);
@@ -316,6 +320,19 @@ bool perf_cpu_map__has_any_cpu_or_is_empty(const struct perf_cpu_map *map)
 	return map ? __perf_cpu_map__cpu(map, 0).cpu == -1 : true;
 }
 
+bool perf_cpu_map__is_any_cpu_or_is_empty(const struct perf_cpu_map *map)
+{
+	if (!map)
+		return true;
+
+	return __perf_cpu_map__nr(map) == 1 && __perf_cpu_map__cpu(map, 0).cpu == -1;
+}
+
+bool perf_cpu_map__is_empty(const struct perf_cpu_map *map)
+{
+	return map == NULL;
+}
+
 int perf_cpu_map__idx(const struct perf_cpu_map *cpus, struct perf_cpu cpu)
 {
 	int low, high;
@@ -372,6 +389,20 @@ bool perf_cpu_map__has_any_cpu(const struct perf_cpu_map *map)
 	return map && __perf_cpu_map__cpu(map, 0).cpu == -1;
 }
 
+struct perf_cpu perf_cpu_map__min(const struct perf_cpu_map *map)
+{
+	struct perf_cpu cpu, result = {
+		.cpu = -1
+	};
+	int idx;
+
+	perf_cpu_map__for_each_cpu_skip_any(cpu, idx, map) {
+		result = cpu;
+		break;
+	}
+	return result;
+}
+
 struct perf_cpu perf_cpu_map__max(const struct perf_cpu_map *map)
 {
 	struct perf_cpu result = {
diff --git a/tools/lib/perf/include/perf/cpumap.h b/tools/lib/perf/include/perf/cpumap.h
index 228c6c629b..90457d17fb 100644
--- a/tools/lib/perf/include/perf/cpumap.h
+++ b/tools/lib/perf/include/perf/cpumap.h
@@ -61,6 +61,22 @@ LIBPERF_API int perf_cpu_map__nr(const struct perf_cpu_map *cpus);
  * perf_cpu_map__has_any_cpu_or_is_empty - is map either empty or has the "any CPU"/dummy value.
  */
 LIBPERF_API bool perf_cpu_map__has_any_cpu_or_is_empty(const struct perf_cpu_map *map);
+/**
+ * perf_cpu_map__is_any_cpu_or_is_empty - is map either empty or the "any CPU"/dummy value.
+ */
+LIBPERF_API bool perf_cpu_map__is_any_cpu_or_is_empty(const struct perf_cpu_map *map);
+/**
+ * perf_cpu_map__is_empty - does the map contain no values and it doesn't
+ *                          contain the special "any CPU"/dummy value.
+ */
+LIBPERF_API bool perf_cpu_map__is_empty(const struct perf_cpu_map *map);
+/**
+ * perf_cpu_map__min - the minimum CPU value or -1 if empty or just the "any CPU"/dummy value.
+ */
+LIBPERF_API struct perf_cpu perf_cpu_map__min(const struct perf_cpu_map *map);
+/**
+ * perf_cpu_map__max - the maximum CPU value or -1 if empty or just the "any CPU"/dummy value.
+ */
 LIBPERF_API struct perf_cpu perf_cpu_map__max(const struct perf_cpu_map *map);
 LIBPERF_API bool perf_cpu_map__has(const struct perf_cpu_map *map, struct perf_cpu cpu);
 LIBPERF_API bool perf_cpu_map__equal(const struct perf_cpu_map *lhs,
diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map
index 10b3f37226..2aa79b6960 100644
--- a/tools/lib/perf/libperf.map
+++ b/tools/lib/perf/libperf.map
@@ -10,6 +10,10 @@ LIBPERF_0.0.1 {
 		perf_cpu_map__nr;
 		perf_cpu_map__cpu;
 		perf_cpu_map__has_any_cpu_or_is_empty;
+		perf_cpu_map__is_any_cpu_or_is_empty;
+		perf_cpu_map__is_empty;
+		perf_cpu_map__has_any_cpu;
+		perf_cpu_map__min;
 		perf_cpu_map__max;
 		perf_cpu_map__has;
 		perf_thread_map__new_array;
diff --git a/tools/lib/perf/mmap.c b/tools/lib/perf/mmap.c
index 0c903c2372..c1a51d925e 100644
--- a/tools/lib/perf/mmap.c
+++ b/tools/lib/perf/mmap.c
@@ -279,7 +279,7 @@ union perf_event *perf_mmap__read_event(struct perf_mmap *map)
 	if (!refcount_read(&map->refcnt))
 		return NULL;
 
-	/* non-overwirte doesn't pause the ringbuffer */
+	/* non-overwrite doesn't pause the ringbuffer */
 	if (!map->overwrite)
 		map->end = perf_mmap__read_head(map);