3 files changed, 71 insertions, 5 deletions

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 901a58fa3f2..0247acfdfac 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -653,6 +653,65 @@ struct dso *dso__kernel_findnew(struct machine *machine, const char *name,
 	return dso;
 }
 
+/*
+ * Find a matching entry and/or link current entry to RB tree.
+ * Either one of the dso or name parameter must be non-NULL or the
+ * function will not work.
+ */
+static struct dso *dso__findlink_by_longname(struct rb_root *root,
+					     struct dso *dso, const char *name)
+{
+	struct rb_node **p = &root->rb_node;
+	struct rb_node  *parent = NULL;
+
+	if (!name)
+		name = dso->long_name;
+	/*
+	 * Find node with the matching name
+	 */
+	while (*p) {
+		struct dso *this = rb_entry(*p, struct dso, rb_node);
+		int rc = strcmp(name, this->long_name);
+
+		parent = *p;
+		if (rc == 0) {
+			/*
+			 * In case the new DSO is a duplicate of an existing
+			 * one, print an one-time warning & put the new entry
+			 * at the end of the list of duplicates.
+			 */
+			if (!dso || (dso == this))
+				return this;	/* Find matching dso */
+			/*
+			 * The core kernel DSOs may have duplicated long name.
+			 * In this case, the short name should be different.
+			 * Comparing the short names to differentiate the DSOs.
+			 */
+			rc = strcmp(dso->short_name, this->short_name);
+			if (rc == 0) {
+				pr_err("Duplicated dso name: %s\n", name);
+				return NULL;
+			}
+		}
+		if (rc < 0)
+			p = &parent->rb_left;
+		else
+			p = &parent->rb_right;
+	}
+	if (dso) {
+		/* Add new node and rebalance tree */
+		rb_link_node(&dso->rb_node, parent, p);
+		rb_insert_color(&dso->rb_node, root);
+	}
+	return NULL;
+}
+
+static inline struct dso *
+dso__find_by_longname(const struct rb_root *root, const char *name)
+{
+	return dso__findlink_by_longname((struct rb_root *)root, NULL, name);
+}
+
 void dso__set_long_name(struct dso *dso, const char *name, bool name_allocated)
 {
 	if (name == NULL)
@@ -755,6 +814,7 @@ struct dso *dso__new(const char *name)
 		dso->a2l_fails = 1;
 		dso->kernel = DSO_TYPE_USER;
 		dso->needs_swap = DSO_SWAP__UNSET;
+		RB_CLEAR_NODE(&dso->rb_node);
 		INIT_LIST_HEAD(&dso->node);
 		INIT_LIST_HEAD(&dso->data.open_entry);
 	}
@@ -765,6 +825,10 @@ struct dso *dso__new(const char *name)
 void dso__delete(struct dso *dso)
 {
 	int i;
+
+	if (!RB_EMPTY_NODE(&dso->rb_node))
+		pr_err("DSO %s is still in rbtree when being deleted!\n",
+		       dso->long_name);
 	for (i = 0; i < MAP__NR_TYPES; ++i)
 		symbols__delete(&dso->symbols[i]);
 
@@ -854,6 +918,7 @@ bool __dsos__read_build_ids(struct list_head *head, bool with_hits)
 void dsos__add(struct dsos *dsos, struct dso *dso)
 {
 	list_add_tail(&dso->node, &dsos->head);
+	dso__findlink_by_longname(&dsos->root, dso, NULL);
 }
 
 struct dso *dsos__find(const struct dsos *dsos, const char *name,
@@ -867,10 +932,7 @@ struct dso *dsos__find(const struct dsos *dsos, const char *name,
 				return pos;
 		return NULL;
 	}
-	list_for_each_entry(pos, &dsos->head, node)
-		if (strcmp(pos->long_name, name) == 0)
-			return pos;
-	return NULL;
+	return dso__find_by_longname(&dsos->root, name);
 }
 
 struct dso *__dsos__findnew(struct dsos *dsos, const char *name)
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index b63dc98ad71..acb651acc7f 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -91,14 +91,17 @@ struct dso_cache {
 };
 
 /*
- * DSOs are put into a list for fast iteration.
+ * DSOs are put into both a list for fast iteration and rbtree for fast
+ * long name lookup.
  */
 struct dsos {
 	struct list_head head;
+	struct rb_root	 root;	/* rbtree root sorted by long name */
 };
 
 struct dso {
 	struct list_head node;
+	struct rb_node	 rb_node;	/* rbtree node sorted by long name */
 	struct rb_root	 symbols[MAP__NR_TYPES];
 	struct rb_root	 symbol_names[MAP__NR_TYPES];
 	void		 *a2l;
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 49a75ec4c47..b7d477fbda0 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -77,6 +77,7 @@ static void dsos__delete(struct dsos *dsos)
 	struct dso *pos, *n;
 
 	list_for_each_entry_safe(pos, n, &dsos->head, node) {
+		RB_CLEAR_NODE(&pos->rb_node);
 		list_del(&pos->node);
 		dso__delete(pos);
 	}