1 files changed, 17 insertions, 0 deletions
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index dc2212e12184..abb608b09269 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -23,8 +23,10 @@
 #include "util.h"
 #include "sort.h"
 #include "machine.h"
+#include "map.h"
 #include "callchain.h"
 #include "branch.h"
+#include "symbol.h"
 
 #define CALLCHAIN_PARAM_DEFAULT			\
 	.mode		= CHAIN_GRAPH_ABS,	\
@@ -1577,3 +1579,18 @@ int callchain_cursor__copy(struct callchain_cursor *dst,
 
 	return rc;
 }
+
+/*
+ * Initialize a cursor before adding entries inside, but keep
+ * the previously allocated entries as a cache.
+ */
+void callchain_cursor_reset(struct callchain_cursor *cursor)
+{
+	struct callchain_cursor_node *node;
+
+	cursor->nr = 0;
+	cursor->last = &cursor->first;
+
+	for (node = cursor->first; node != NULL; node = node->next)
+		map__zput(node->map);
+}