--- old/src/share/vm/gc/cms/parCardTableModRefBS.cpp	2015-05-20 10:55:48.626718164 +0200
+++ new/src/share/vm/gc/cms/parCardTableModRefBS.cpp	2015-05-20 10:55:48.498713846 +0200
@@ -41,7 +41,8 @@
                                                              CardTableRS* ct,
                                                              uint n_threads) {
   assert(n_threads > 0, "Error: expected n_threads > 0");
-  assert(n_threads <= (uint)ParallelGCThreads, "# worker threads != # requested!");
+  assert(n_threads <= (uint)ParallelGCThreads,
+         err_msg("Error: n_threads: %u > ParallelGCThreads: %u", n_threads, (uint)ParallelGCThreads));
 
   // Make sure the LNC array is valid for the space.
   jbyte**   lowest_non_clean;
@@ -58,12 +59,9 @@
   pst->set_n_threads(n_threads);
   pst->set_n_tasks(n_strides);
 
-  bool parallel = n_threads > 0;
-
   uint stride = 0;
   while (!pst->is_task_claimed(/* reference */ stride)) {
     process_stride(sp, mr, stride, n_strides,
-	               parallel,
                    cl, ct,
                    lowest_non_clean,
                    lowest_non_clean_base_chunk_index,
@@ -87,7 +85,6 @@
 process_stride(Space* sp,
                MemRegion used,
                jint stride, int n_strides,
-               bool parallel,
                OopsInGenClosure* cl,
                CardTableRS* ct,
                jbyte** lowest_non_clean,
@@ -131,6 +128,9 @@
     assert(chunk_mr.word_size() > 0, "[chunk_card_start > used_end)");
     assert(used.contains(chunk_mr), "chunk_mr should be subset of used");
 
+    // This function is used by the parallel card table iteration.
+    const bool parallel = true;
+
     DirtyCardToOopClosure* dcto_cl = sp->new_dcto_cl(cl, precision(),
                                                      cl->gen_boundary(),
                                                      parallel);
--- old/src/share/vm/gc/shared/cardTableModRefBS.cpp	2015-05-20 10:55:48.894727204 +0200
+++ new/src/share/vm/gc/shared/cardTableModRefBS.cpp	2015-05-20 10:55:48.738721942 +0200
@@ -452,8 +452,11 @@
     } else {
       // clear_cl finds contiguous dirty ranges of cards to process and clear.
 
-      DirtyCardToOopClosure* dcto_cl = sp->new_dcto_cl(cl, precision(), cl->gen_boundary(), false);
-      ClearNoncleanCardWrapper clear_cl(dcto_cl, ct, false);
+      // This is the single-threaded version.
+      const bool parallel = false;
+
+      DirtyCardToOopClosure* dcto_cl = sp->new_dcto_cl(cl, precision(), cl->gen_boundary(), parallel);
+      ClearNoncleanCardWrapper clear_cl(dcto_cl, ct, parallel);
 
       clear_cl.do_MemRegion(mr);
     }
--- old/src/share/vm/gc/shared/cardTableModRefBS.hpp	2015-05-20 10:55:49.146735704 +0200
+++ new/src/share/vm/gc/shared/cardTableModRefBS.hpp	2015-05-20 10:55:49.002730846 +0200
@@ -239,7 +239,6 @@
   void process_stride(Space* sp,
                       MemRegion used,
                       jint stride, int n_strides,
-                      bool parallel,
                       OopsInGenClosure* cl,
                       CardTableRS* ct,
                       jbyte** lowest_non_clean,