GH-555 use FileChannel.MapMode.PRIVATE on macOS aarch64

Author: thurka

visualvm/libs.profiler/lib.profiler.heap/src/org/graalvm/visualvm/lib/jfluid/heap/AbstractLongMap.java

@@ -205,6 +205,18 @@ private static boolean isLinux() {
         return osName.endsWith("Linux"); // NOI18N
     }
 
+    private static boolean isMacOS() {
+        String osName = System.getProperty("os.name");  // NOI18N
+
+        return "Mac OS X".equals(osName); // NOI18N
+    }
+
+    private static boolean isAarch64() {
+        String osArch = System.getProperty("os.arch");  // NOI18N
+
+        return "aarch64".equals(osArch); // NOI18N
+    }
+
     abstract Entry createEntry(long index);
 
     abstract Entry createEntry(long index,long value);
@@ -379,7 +391,7 @@ public void force() throws IOException {
 
     private static class MemoryMappedData extends AbstractData {
 
-        private static final FileChannel.MapMode MAP_MODE = isLinux() ? FileChannel.MapMode.PRIVATE : FileChannel.MapMode.READ_WRITE;
+        private static final FileChannel.MapMode MAP_MODE = computeMapMode();
 
         //~ Instance fields ------------------------------------------------------------------------------------------------------
 
@@ -439,6 +451,12 @@ private static MappedByteBuffer createBuffer(RandomAccessFile file, long length)
                 return channel.map(MAP_MODE, 0, length);
             }
         }
+
+        private static FileChannel.MapMode computeMapMode() {
+            if (isLinux()) return FileChannel.MapMode.PRIVATE;
+            if (isMacOS() && isAarch64()) return FileChannel.MapMode.PRIVATE;
+            return FileChannel.MapMode.READ_WRITE;
+        }
     }
 
     private static class LongMemoryMappedData extends AbstractData {