diff --git a/package.json b/package.json
index 1e8339e..f8bf025 100644
--- a/package.json
+++ b/package.json
@@ -61,7 +61,8 @@
         "php.memoryLimit": {
           "type": "string",
           "default": "-1",
-          "description": "The memory limit of the php language server. [Number][K|M|G]. Use '-1' to allow unlimited use of the RAM(default)."
+          "description": "The memory limit of the php language server. [Number][K|M|G]. Use '-1' to allow unlimited use of the RAM(default).",
+          "schema": "!/^\d+(?:K|M|G|)$/"
         }
       }
     }
diff --git a/src/extension.ts b/src/extension.ts
index 8f5f491..6bce406 100644
--- a/src/extension.ts
+++ b/src/extension.ts
@@ -14,7 +14,7 @@ export async function activate(context: vscode.ExtensionContext): Promise<void>
 
     const memoryLimit = conf.get<string>('memoryLimit') || '-1';
 
-    if (memoryLimit !== '-1' && !memoryLimit.match('~^(\d+)(K|M|G|)$~')) {
+    if (memoryLimit !== '-1' && !/^\d+(?:K|M|G|)$/.exec(memoryLimit)) {
         const selected = await vscode.window.showErrorMessage(
             'The memory limit you\'d provided is not numeric, nor "-1" nor valid php shorthand notation!',
             'Open settings'