diff -r 8859772195c6 -r 0414c1049f15 src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp
--- a/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Tue Feb 09 13:56:09 2010 -0800
+++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Thu Feb 11 15:52:19 2010 -0800
@@ -2646,6 +2646,13 @@
 
 // </NEW PREDICTION>
 
+struct PrepareForRSScanningClosure : public HeapRegionClosure {
+  bool doHeapRegion(HeapRegion *r) {
+    r->rem_set()->set_iter_claimed(0);
+    return false;
+  }
+};
+
 void
 G1CollectedHeap::do_collection_pause_at_safepoint() {
   if (PrintHeapAtGC) {
@@ -2784,6 +2791,8 @@
         gclog_or_tty->print_cr("\nAfter pause, heap:");
         print();
 #endif
+        PrepareForRSScanningClosure prepare_for_rs_scan;
+        collection_set_iterate(&prepare_for_rs_scan);
 
         setup_surviving_young_words();
 
@@ -3781,22 +3790,16 @@
   return obj;
 }
 
-template <bool do_gen_barrier, G1Barrier barrier, bool do_mark_forwardee, bool skip_cset_test>
+template <bool do_gen_barrier, G1Barrier barrier, bool do_mark_forwardee>
 template <class T>
-void G1ParCopyClosure <do_gen_barrier, barrier, do_mark_forwardee, skip_cset_test>
+void G1ParCopyClosure <do_gen_barrier, barrier, do_mark_forwardee>
 ::do_oop_work(T* p) {
   oop obj = oopDesc::load_decode_heap_oop(p);
   assert(barrier != G1BarrierRS || obj != NULL,
          "Precondition: G1BarrierRS implies obj is nonNull");
 
-  // The only time we skip the cset test is when we're scanning
-  // references popped from the queue. And we only push on the queue
-  // references that we know point into the cset, so no point in
-  // checking again. But we'll leave an assert here for peace of mind.
-  assert(!skip_cset_test || _g1->obj_in_cs(obj), "invariant");
-
   // here the null check is implicit in the cset_fast_test() test
-  if (skip_cset_test || _g1->in_cset_fast_test(obj)) {
+  if (_g1->in_cset_fast_test(obj)) {
 #if G1_REM_SET_LOGGING
     gclog_or_tty->print_cr("Loc "PTR_FORMAT" contains pointer "PTR_FORMAT" "
                            "into CS.", p, (void*) obj);
@@ -3813,7 +3816,6 @@
     }
   }
 
-  // When scanning moved objs, must look at all oops.
   if (barrier == G1BarrierEvac && obj != NULL) {
     _par_scan_state->update_rs(_from, p, _par_scan_state->queue_num());
   }
@@ -3823,8 +3825,8 @@
   }
 }
 
-template void G1ParCopyClosure<false, G1BarrierEvac, false, true>::do_oop_work(oop* p);
-template void G1ParCopyClosure<false, G1BarrierEvac, false, true>::do_oop_work(narrowOop* p);
+template void G1ParCopyClosure<false, G1BarrierEvac, false>::do_oop_work(oop* p);
+template void G1ParCopyClosure<false, G1BarrierEvac, false>::do_oop_work(narrowOop* p);
 
 template <class T> void G1ParScanPartialArrayClosure::do_oop_nv(T* p) {
   assert(has_partial_array_mask(p), "invariant");
@@ -3896,11 +3898,11 @@
           assert(UseCompressedOops, "Error");
           narrowOop* p = (narrowOop*) stolen_task;
           assert(has_partial_array_mask(p) ||
-                 _g1h->obj_in_cs(oopDesc::load_decode_heap_oop(p)), "Error");
+                 _g1h->is_in_g1_reserved(oopDesc::load_decode_heap_oop(p)), "Error");
           pss->push_on_queue(p);
         } else {
           oop* p = (oop*) stolen_task;
-          assert(has_partial_array_mask(p) || _g1h->obj_in_cs(*p), "Error");
+          assert(has_partial_array_mask(p) || _g1h->is_in_g1_reserved(*p), "Error");
           pss->push_on_queue(p);
         }
         continue;
@@ -3962,6 +3964,7 @@
     G1ParScanExtRootClosure         only_scan_root_cl(_g1h, &pss);
     G1ParScanPermClosure            only_scan_perm_cl(_g1h, &pss);
     G1ParScanHeapRSClosure          only_scan_heap_rs_cl(_g1h, &pss);
+    G1ParPushHeapRSClosure          push_heap_rs_cl(_g1h, &pss);
 
     G1ParScanAndMarkExtRootClosure  scan_mark_root_cl(_g1h, &pss);
     G1ParScanAndMarkPermClosure     scan_mark_perm_cl(_g1h, &pss);
@@ -3985,7 +3988,7 @@
     _g1h->g1_process_strong_roots(/* not collecting perm */ false,
                                   SharedHeap::SO_AllClasses,
                                   scan_root_cl,
-                                  &only_scan_heap_rs_cl,
+                                  &push_heap_rs_cl,
                                   scan_so_cl,
                                   scan_perm_cl,
                                   i);