src/share/vm/gc_implementation/g1/heapRegion.cpp

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rev 5920 : 8035406: Improve data structure for Code Cache remembered sets
Summary: Change the code cache remembered sets data structure from a GrowableArray to a chunked list of nmethods. This makes the data structure more amenable to parallelization, and decreases freeing time.
Reviewed-by:
rev 5921 : 8027295: Free CSet takes ~50% of young pause time
Summary: Improve fast card cache iteration and avoid taking locks when freeing the collection set.
Reviewed-by:

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.

@@ -203,11 +203,11 @@
   // treat all objects as being inside the unmarked area.
   zero_marked_bytes();
   init_top_at_mark_start();
 }
 
-void HeapRegion::hr_clear(bool par, bool clear_space) {
+void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
   assert(_humongous_type == NotHumongous,
          "we should have already filtered out humongous regions");
   assert(_humongous_start_region == NULL,
          "we should have already filtered out humongous regions");
   assert(_end == _orig_end,

@@ -221,11 +221,15 @@
   reset_pre_dummy_top();
 
   if (!par) {
     // If this is parallel, this will be done later.
     HeapRegionRemSet* hrrs = rem_set();
+    if (locked) {
+      hrrs->clear_locked();
+    } else {
     hrrs->clear();
+    }
     _claimed = InitialClaimValue;
   }
   zero_marked_bytes();
 
   _offsets.resize(HeapRegion::GrainWords);