perf tools: Don't trow away old map slices not overlapped by new maps

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1267800842-22324-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/util/thread.c

@@ -183,7 +183,7 @@ struct thread *perf_session__findnew(struct perf_session *self, pid_t pid)
 	return th;
 }
 
-static void map_groups__remove_overlappings(struct map_groups *self,
+static int map_groups__fixup_overlappings(struct map_groups *self,
 					  struct map *map)
 {
 	struct rb_root *root = &self->maps[map->type];
@@ -209,7 +209,36 @@ static void map_groups__remove_overlappings(struct map_groups *self,
 		 * list.
 		 */
 		list_add_tail(&pos->node, &self->removed_maps[map->type]);
+		/*
+		 * Now check if we need to create new maps for areas not
+		 * overlapped by the new map:
+		 */
+		if (map->start > pos->start) {
+			struct map *before = map__clone(pos);
+
+			if (before == NULL)
+				return -ENOMEM;
+
+			before->end = map->start - 1;
+			map_groups__insert(self, before);
+			if (verbose >= 2)
+				map__fprintf(before, stderr);
 		}
+
+		if (map->end < pos->end) {
+			struct map *after = map__clone(pos);
+
+			if (after == NULL)
+				return -ENOMEM;
+
+			after->start = map->end + 1;
+			map_groups__insert(self, after);
+			if (verbose >= 2)
+				map__fprintf(after, stderr);
+		}
+	}
+
+	return 0;
 }
 
 void maps__insert(struct rb_root *maps, struct map *map)
@@ -254,7 +283,7 @@ struct map *maps__find(struct rb_root *maps, u64 ip)
 
 void thread__insert_map(struct thread *self, struct map *map)
 {
-	map_groups__remove_overlappings(&self->mg, map);
+	map_groups__fixup_overlappings(&self->mg, map);
 	map_groups__insert(&self->mg, map);
 }