--- old/src/share/vm/gc_implementation/parallelScavenge/psOldGen.cpp	2010-03-10 14:49:35.000000000 -0800
+++ new/src/share/vm/gc_implementation/parallelScavenge/psOldGen.cpp	2010-03-10 14:49:35.000000000 -0800
@@ -308,16 +308,16 @@
   size_t size = align_size_down(bytes, virtual_space()->alignment());
   if (size > 0) {
     assert_lock_strong(ExpandHeap_lock);
-    virtual_space()->shrink_by(bytes);
+    virtual_space()->shrink_by(size);
     post_resize();
 
     if (Verbose && PrintGC) {
       size_t new_mem_size = virtual_space()->committed_size();
-      size_t old_mem_size = new_mem_size + bytes;
+      size_t old_mem_size = new_mem_size + size;
       gclog_or_tty->print_cr("Shrinking %s from " SIZE_FORMAT "K by "
                                          SIZE_FORMAT "K to "
                                          SIZE_FORMAT "K",
-                      name(), old_mem_size/K, bytes/K, new_mem_size/K);
+                      name(), old_mem_size/K, size/K, new_mem_size/K);
     }
   }
 }
@@ -497,3 +497,26 @@
   object_space()->set_top_for_allocations();
 }
 #endif
+
+void PSOldGen::try_to_shrink_by(size_t shrink_bytes) {
+  if (shrink_bytes < MinHeapDeltaBytes ||
+      capacity_in_bytes() - shrink_bytes < _init_gen_size) {
+    return;
+  }
+
+  if (PrintGC) {
+    gclog_or_tty->print_cr(" Resizing old gen. shrink_bytes=%d", shrink_bytes);
+    gclog_or_tty->print("BEFORE: Old Gen: ");
+    gclog_or_tty->print("capacity : " SIZE_FORMAT ", ", capacity_in_bytes());
+    gclog_or_tty->print_cr("used : " SIZE_FORMAT ", " , used_in_bytes());
+  }
+
+  MutexLocker x(ExpandHeap_lock);
+  shrink(shrink_bytes);
+
+  if (PrintGC) {
+    gclog_or_tty->print("AFTER: Old Gen: ");
+    gclog_or_tty->print("capacity : " SIZE_FORMAT ", ", capacity_in_bytes());
+    gclog_or_tty->print_cr("used : " SIZE_FORMAT ", " , used_in_bytes());
+  }
+}