diff --git a/modules/block/block.admin.inc b/modules/block/block.admin.inc
index a0ecb48df1c320ab8423966758e2398d7bcd7cc8..c0f3c4789425978df63360de8e9455c3d8568cc3 100644
--- a/modules/block/block.admin.inc
+++ b/modules/block/block.admin.inc
@@ -6,30 +6,6 @@
  * Admin page callbacks for the block module.
  */
 
-/**
- * Implement hook_form_FORM_ID_alter().
- */
-function block_form_system_performance_settings_alter(&$form, &$form_state) {
-  $disabled = count(module_implements('node_grants'));
-  $form['caching']['block_cache'] = array(
-    '#type' => 'checkbox',
-    '#title' => t('Cache blocks'),
-    '#default_value' => variable_get('block_cache', FALSE),
-    '#disabled' => $disabled,
-    '#description' => $disabled ? t('Block caching is inactive because you have enabled modules defining content access restrictions.') : NULL,
-    '#weight' => -1,
-  );
-
-  // Check if the "Who's online" block is enabled.
-  $online_block_enabled = db_query_range("SELECT 1 FROM {block} b WHERE module = 'user' AND delta = 'online' AND status = 1", array(), 0, 1)->fetchField();
-
-  // If the "Who's online" block is enabled, append some descriptive text to
-  // the end of the form description.
-  if ($online_block_enabled) {
-    $form['page_cache']['cache']['#description'] .=  '<p>' . t('When caching is enabled, anonymous user sessions are only saved to the database when needed, so the "Who\'s online" block does not display the number of anonymous users.') . '</p>';
-  }
-}
-
 /**
  * Menu callback for admin/structure/block.
  */
diff --git a/modules/block/block.module b/modules/block/block.module
index 55f34ac2b08add8306d6ac1148fad59ea6a4f934..e12b06a66496fe12dbfe20818d1bb4dec9a41d73 100644
--- a/modules/block/block.module
+++ b/modules/block/block.module
@@ -805,3 +805,26 @@ function block_filter_format_delete($format, $default) {
     ->execute();
 }
 
+/**
+ * Implement hook_form_FORM_ID_alter().
+ */
+function block_form_system_performance_settings_alter(&$form, &$form_state) {
+  $disabled = count(module_implements('node_grants'));
+  $form['caching']['block_cache'] = array(
+    '#type' => 'checkbox',
+    '#title' => t('Cache blocks'),
+    '#default_value' => variable_get('block_cache', FALSE),
+    '#disabled' => $disabled,
+    '#description' => $disabled ? t('Block caching is inactive because you have enabled modules defining content access restrictions.') : NULL,
+    '#weight' => -1,
+  );
+
+  // Check if the "Who's online" block is enabled.
+  $online_block_enabled = db_query_range("SELECT 1 FROM {block} b WHERE module = 'user' AND delta = 'online' AND status = 1", array(), 0, 1)->fetchField();
+
+  // If the "Who's online" block is enabled, append some descriptive text to
+  // the end of the form description.
+  if ($online_block_enabled) {
+    $form['page_cache']['cache']['#description'] .=  '<p>' . t('When caching is enabled, anonymous user sessions are only saved to the database when needed, so the "Who\'s online" block does not display the number of anonymous users.') . '</p>';
+  }
+}