diff --git a/src/Psalm/Internal/Fork/PsalmRestarter.php b/src/Psalm/Internal/Fork/PsalmRestarter.php
index 53de9ec014c..af4d83776b8 100644
--- a/src/Psalm/Internal/Fork/PsalmRestarter.php
+++ b/src/Psalm/Internal/Fork/PsalmRestarter.php
@@ -84,6 +84,11 @@ protected function requiresRestart($default): bool
             }
         }
 
+        // opcache.save_comments is required for json mapper (used in language server) to work
+        if ($opcache_loaded && in_array(ini_get('opcache.save_comments'), ['0', 'false', 0, false])) {
+            return true;
+        }
+
         return $default || $this->required;
     }
 
@@ -152,6 +157,10 @@ protected function restart($command): void
             ];
         }
 
+        if ($opcache_loaded) {
+            $additional_options[] = '-dopcache.save_comments=1';
+        }
+
         array_splice(
             $command,
             1,