8354347: Increase the default padding size for aarch64 in JDK code.

Reviewed-by: aph, ecaspole

Author: Peter B. Kessler

src/hotspot/cpu/aarch64/globalDefinitions_aarch64.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2025, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2014, 2015, Red Hat Inc. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -46,7 +46,7 @@ const bool CCallingConventionRequiresIntsAsLongs = false;
 #define DEFAULT_CACHE_LINE_SIZE 64
 
 // The default padding size for data structures to avoid false sharing.
-#define DEFAULT_PADDING_SIZE DEFAULT_CACHE_LINE_SIZE
+#define DEFAULT_PADDING_SIZE (2*DEFAULT_CACHE_LINE_SIZE)
 
 // According to the ARMv8 ARM, "Concurrent modification and execution
 // of instructions can lead to the resulting instruction performing