# HG changeset patch
# User kvn
# Date 1286294240 25200
# Node ID fe08403130db4318135b95acb492d2b2dc301397
# Parent  3f9a70eb8b1f994158cfa78c1b833acb04caa0ed
6979458: VM crashes when -XX:ObjectAlignmentInBytes is too big
Summary: Set upper limit 256 for ObjectAlignmentInBytes value.
Reviewed-by: never, iveresov

diff -r 3f9a70eb8b1f -r fe08403130db src/share/vm/runtime/arguments.cpp
--- a/src/share/vm/runtime/arguments.cpp	Tue Oct 05 00:19:21 2010 -0700
+++ b/src/share/vm/runtime/arguments.cpp	Tue Oct 05 08:57:20 2010 -0700
@@ -1261,12 +1261,30 @@
   // Object alignment.
   if (!is_power_of_2(ObjectAlignmentInBytes)) {
     jio_fprintf(defaultStream::error_stream(),
-                "error: ObjectAlignmentInBytes=%d must be power of 2", (int)ObjectAlignmentInBytes);
+                "error: ObjectAlignmentInBytes=%d must be power of 2\n",
+                (int)ObjectAlignmentInBytes);
     return false;
   }
   if ((int)ObjectAlignmentInBytes < BytesPerLong) {
     jio_fprintf(defaultStream::error_stream(),
-                "error: ObjectAlignmentInBytes=%d must be greater or equal %d", (int)ObjectAlignmentInBytes, BytesPerLong);
+                "error: ObjectAlignmentInBytes=%d must be greater or equal %d\n",
+                (int)ObjectAlignmentInBytes, BytesPerLong);
+    return false;
+  }
+  // It does not make sense to have big object alignment
+  // since a space lost due to alignment will be greater
+  // then a saved space from compressed oops.
+  if ((int)ObjectAlignmentInBytes > 256) {
+    jio_fprintf(defaultStream::error_stream(),
+                "error: ObjectAlignmentInBytes=%d must not be greater then 256\n",
+                (int)ObjectAlignmentInBytes);
+    return false;
+  }
+  // In case page size is very small.
+  if ((int)ObjectAlignmentInBytes >= os::vm_page_size()) {
+    jio_fprintf(defaultStream::error_stream(),
+                "error: ObjectAlignmentInBytes=%d must be less then page size %d\n",
+                (int)ObjectAlignmentInBytes, os::vm_page_size());
     return false;
   }
   return true;