--- old/src/share/vm/gc_implementation/g1/g1SATBCardTableModRefBS.cpp	2013-10-07 16:51:29.325387168 +0200
+++ new/src/share/vm/gc_implementation/g1/g1SATBCardTableModRefBS.cpp	2013-10-07 16:51:29.245387171 +0200
@@ -161,30 +161,34 @@
       byte++;
     }
   } else {
-    // Enqueue if necessary.
-    if (thr->is_Java_thread()) {
-      JavaThread* jt = (JavaThread*)thr;
-      for (; byte <= last_byte; byte++) {
-        if (*byte == g1_young_gen) {
-          continue;
+    // skip all consecutive young cards
+    for (; byte <= last_byte && *byte == g1_young_gen; byte++);
+
+    if (byte <= last_byte) {
+      OrderAccess::storeload();
+      // Enqueue if necessary.
+      if (thr->is_Java_thread()) {
+        JavaThread* jt = (JavaThread*)thr;
+        for (; byte <= last_byte; byte++) {
+          if (*byte == g1_young_gen) {
+            continue;
+          }
+          if (*byte != dirty_card) {
+            *byte = dirty_card;
+            jt->dirty_card_queue().enqueue(byte);
+          }
         }
-        OrderAccess::storeload();
-        if (*byte != dirty_card) {
-          *byte = dirty_card;
-          jt->dirty_card_queue().enqueue(byte);
-        }
-      }
-    } else {
-      MutexLockerEx x(Shared_DirtyCardQ_lock,
-                      Mutex::_no_safepoint_check_flag);
-      for (; byte <= last_byte; byte++) {
-        if (*byte == g1_young_gen) {
-          continue;
-        }
-        OrderAccess::storeload();
-        if (*byte != dirty_card) {
-          *byte = dirty_card;
-          _dcqs.shared_dirty_card_queue()->enqueue(byte);
+      } else {
+        MutexLockerEx x(Shared_DirtyCardQ_lock,
+                        Mutex::_no_safepoint_check_flag);
+        for (; byte <= last_byte; byte++) {
+          if (*byte == g1_young_gen) {
+            continue;
+          }
+          if (*byte != dirty_card) {
+            *byte = dirty_card;
+            _dcqs.shared_dirty_card_queue()->enqueue(byte);
+          }
         }
       }
     }