src/share/vm/gc/serial/defNewGeneration.cpp

@@ -36,10 +36,11 @@
 #include "gc/shared/genRemSet.hpp"
 #include "gc/shared/generationSpec.hpp"
 #include "gc/shared/referencePolicy.hpp"
 #include "gc/shared/space.inline.hpp"
 #include "gc/shared/spaceDecorator.hpp"
+#include "gc/shared/strongRootsScope.hpp"
 #include "memory/iterator.hpp"
 #include "oops/instanceRefKlass.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/atomic.inline.hpp"
 #include "runtime/java.hpp"

@@ -452,11 +453,11 @@
       gclog_or_tty->cr();
     }
   }
 }
 
-void DefNewGeneration::younger_refs_iterate(OopsInGenClosure* cl) {
+void DefNewGeneration::younger_refs_iterate(OopsInGenClosure* cl, uint n_threads) {
   assert(false, "NYI -- are you sure you want to call this?");
 }
 
 
 size_t DefNewGeneration::capacity() const {

@@ -623,19 +624,26 @@
                                                   &fsc_with_gc_barrier);
 
   assert(gch->no_allocs_since_save_marks(0),
          "save marks have not been newly set.");
 
-  gch->gen_process_roots(_level,
+  {
+    // DefNew needs to run with n_threads == 0, to make sure the serial
+    // version of the card table scanning code is used.
+    // See: CardTableModRefBS::non_clean_card_iterate_possibly_parallel.
+    StrongRootsScope srs(0);
+
+    gch->gen_process_roots(&srs,
+                           _level,
                          true,  // Process younger gens, if any,
                                 // as strong roots.
-                         true,  // activate StrongRootsScope
                          GenCollectedHeap::SO_ScavengeCodeCache,
                          GenCollectedHeap::StrongAndWeakRoots,
                          &fsc_with_no_gc_barrier,
                          &fsc_with_gc_barrier,
                          &cld_scan_closure);
+  }
 
   // "evacuate followers".
   evacuate_followers.do_void();
 
   FastKeepAliveClosure keep_alive(this, &scan_weak_ref);