1 /*
   2  * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "gc/g1/g1OopClosures.inline.hpp"
  27 #include "gc/g1/g1RootClosures.hpp"
  28 #include "gc/g1/g1SharedClosures.hpp"
  29 
  30 // Closures used for standard G1 evacuation.
  31 class G1EvacuationClosures : public G1EvacuationRootClosures {
  32   G1SharedClosures<G1MarkNone> _closures;
  33 
  34 public:
  35   G1EvacuationClosures(G1CollectedHeap* g1h,
  36                        G1ParScanThreadState* pss,
  37                        bool in_young_gc) :
  38       _closures(g1h, pss, in_young_gc) {}
  39 
  40   OopClosure* weak_oops()   { return &_closures._oops; }
  41   OopClosure* strong_oops() { return &_closures._oops; }
  42 
  43   CLDClosure* weak_clds()             { return &_closures._clds; }
  44   CLDClosure* strong_clds()           { return &_closures._clds; }
  45 
  46   CodeBlobClosure* strong_codeblobs()      { return &_closures._codeblobs; }
  47   CodeBlobClosure* weak_codeblobs()        { return &_closures._codeblobs; }
  48 };
  49 
  50 // Closures used during concurrent start.
  51 // The treatment of "weak" roots is selectable through the template parameter,
  52 // this is usually used to control unloading of classes and interned strings.
  53 template <G1Mark MarkWeak>
  54 class G1ConcurrentStartMarkClosures : public G1EvacuationRootClosures {
  55   G1SharedClosures<G1MarkFromRoot> _strong;
  56   G1SharedClosures<MarkWeak>       _weak;
  57 
  58 public:
  59   G1ConcurrentStartMarkClosures(G1CollectedHeap* g1h,
  60                                 G1ParScanThreadState* pss) :
  61       _strong(g1h, pss, /* process_only_dirty_klasses */ false),
  62       _weak(g1h, pss,   /* process_only_dirty_klasses */ false) {}
  63 
  64   OopClosure* weak_oops()   { return &_weak._oops; }
  65   OopClosure* strong_oops() { return &_strong._oops; }
  66 
  67   CLDClosure* weak_clds()             { return &_weak._clds; }
  68   CLDClosure* strong_clds()           { return &_strong._clds; }
  69 
  70   CodeBlobClosure* strong_codeblobs()      { return &_strong._codeblobs; }
  71   CodeBlobClosure* weak_codeblobs()        { return &_weak._codeblobs; }
  72 };
  73 
  74 G1EvacuationRootClosures* G1EvacuationRootClosures::create_root_closures(G1ParScanThreadState* pss, G1CollectedHeap* g1h) {
  75   G1EvacuationRootClosures* res = NULL;
  76   if (g1h->collector_state()->in_concurrent_start_gc()) {
  77     if (ClassUnloadingWithConcurrentMark) {
  78       res = new G1ConcurrentStartMarkClosures<G1MarkPromotedFromRoot>(g1h, pss);
  79     } else {
  80       res = new G1ConcurrentStartMarkClosures<G1MarkFromRoot>(g1h, pss);
  81     }
  82   } else {
  83     res = new G1EvacuationClosures(g1h, pss, g1h->collector_state()->in_young_only_phase());
  84   }
  85   return res;
  86 }