--- a/hotspot/src/share/vm/gc/cms/compactibleFreeListSpace.cpp	Fri Oct 21 17:51:33 2016 -0700
+++ b/hotspot/src/share/vm/gc/cms/compactibleFreeListSpace.cpp	Fri Oct 21 22:26:51 2016 -0400
@@ -922,18 +922,13 @@
         return res;
       }
     } else {
-      // must read from what 'p' points to in each loop.
-      Klass* k = ((volatile oopDesc*)p)->klass_or_null();
+      // Ensure klass read before size.
+      Klass* k = oop(p)->klass_or_null_acquire();
       if (k != NULL) {
         assert(k->is_klass(), "Should really be klass oop.");
         oop o = (oop)p;
         assert(o->is_oop(true /* ignore mark word */), "Should be an oop.");
 
-        // Bugfix for systems with weak memory model (PPC64/IA64).
-        // The object o may be an array. Acquire to make sure that the array
-        // size (third word) is consistent.
-        OrderAccess::acquire();
-
         size_t res = o->size_given_klass(k);
         res = adjustObjectSize(res);
         assert(res != 0, "Block size should not be 0");
@@ -977,21 +972,13 @@
         return res;
       }
     } else {
-      // must read from what 'p' points to in each loop.
-      Klass* k = ((volatile oopDesc*)p)->klass_or_null();
-      // We trust the size of any object that has a non-NULL
-      // klass and (for those in the perm gen) is parsable
-      // -- irrespective of its conc_safe-ty.
+      // Ensure klass read before size.
+      Klass* k = oop(p)->klass_or_null_acquire();
       if (k != NULL) {
         assert(k->is_klass(), "Should really be klass oop.");
         oop o = (oop)p;
         assert(o->is_oop(), "Should be an oop");
 
-        // Bugfix for systems with weak memory model (PPC64/IA64).
-        // The object o may be an array. Acquire to make sure that the array
-        // size (third word) is consistent.
-        OrderAccess::acquire();
-
         size_t res = o->size_given_klass(k);
         res = adjustObjectSize(res);
         assert(res != 0, "Block size should not be 0");
@@ -1028,7 +1015,7 @@
   FreeChunk* fc = (FreeChunk*)p;
   assert(is_in_reserved(p), "Should be in space");
   if (FreeChunk::indicatesFreeChunk(p)) return false;
-  Klass* k = oop(p)->klass_or_null();
+  Klass* k = oop(p)->klass_or_null_acquire();
   if (k != NULL) {
     // Ignore mark word because it may have been used to
     // chain together promoted objects (the last one