# HG changeset patch
# User Tom Rodriguez <tom.rodriguez@oracle.com>
# Date 1418765313 28800
# Node ID ee26b8eb1601375bc16357421e62fc9ad85d19b8
# Parent  b2859128b76a6f383ed6ec93feac9818b20aca66
Check for overzeroing in the TLAB

diff -r b2859128b76a -r ee26b8eb1601 src/share/vm/memory/threadLocalAllocBuffer.cpp
--- a/src/share/vm/memory/threadLocalAllocBuffer.cpp	Tue Dec 16 10:20:43 2014 -0800
+++ b/src/share/vm/memory/threadLocalAllocBuffer.cpp	Tue Dec 16 13:28:33 2014 -0800
@@ -42,6 +42,9 @@
 
 void ThreadLocalAllocBuffer::clear_before_allocation() {
   _slow_refill_waste += (unsigned)remaining();
+  // In debug mode we expect the storage above top to be uninitialized
+  // or filled with a padding object.
+  assert(top() == NULL || *(intptr_t*)top() != 0, "overzeroing detected");
   make_parsable(true);   // also retire the TLAB
 }