diff --git a/src/lint/linter/ArcanistLinter.php b/src/lint/linter/ArcanistLinter.php
--- a/src/lint/linter/ArcanistLinter.php
+++ b/src/lint/linter/ArcanistLinter.php
@@ -314,7 +314,19 @@
   }
 
   final public function getPaths() {
-    return $this->filterPaths(array_values($this->paths));
+    static $paths;
+    static $filtered_paths;
+
+    if ($paths != $this->paths) {
+      $paths = $this->paths;
+      $filtered_paths = null;
+    }
+
+    if ($filtered_paths == null) {
+      $filtered_paths = $this->filterPaths(array_values($paths));
+    }
+
+    return $filtered_paths;
   }
 
   final public function addData($path, $data) {