1 /*
   2  * Copyright (c) 2017, 2018, Red Hat, Inc. All rights reserved.
   3  *
   4  * This code is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This code is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  11  * version 2 for more details (a copy is included in the LICENSE file that
  12  * accompanied this code).
  13  *
  14  * You should have received a copy of the GNU General Public License version
  15  * 2 along with this work; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  17  *
  18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  19  * or visit www.oracle.com if you need additional information or have any
  20  * questions.
  21  *
  22  */
  23 
  24 #ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHSTRINGDEDUPQUEUE_HPP
  25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHSTRINGDEDUPQUEUE_HPP
  26 
  27 #include "gc_implementation/shenandoah/shenandoahHeap.hpp"
  28 #include "memory/iterator.hpp"
  29 #include "oops/oop.hpp"
  30 #include "runtime/mutex.hpp"
  31 
  32 template <size_t SIZE>
  33 class ShenandoahStrDedupChunkedList : public CHeapObj<mtGC> {
  34 private:
  35   oop                                   _oops[SIZE];
  36   ShenandoahStrDedupChunkedList<SIZE>*  _next;
  37   uint                                  _index;
  38 
  39 public:
  40   ShenandoahStrDedupChunkedList() : _next(NULL), _index(0) { }
  41 
  42   inline bool is_full() const  { return _index == SIZE; }
  43   inline bool is_empty() const { return _index == 0; }
  44   inline void push(oop obj)    { assert(!is_full(), "List is full");  _oops[_index ++] = obj; }
  45   inline oop  pop()            { assert(!is_empty(), "List is empty"); return _oops[--_index]; }
  46   inline size_t size() const   { return _index; }
  47   inline void reset() {
  48     _index = 0;
  49     _next = NULL;
  50   }
  51 
  52   void set_next(ShenandoahStrDedupChunkedList<SIZE>* q) { _next = q; }
  53   ShenandoahStrDedupChunkedList<SIZE>* next() const { return _next; }
  54 
  55   void oops_do(OopClosure* cl) {
  56     assert(cl != NULL, "null closure");
  57     for (uint index = 0; index < size(); index ++) {
  58       cl->do_oop(&_oops[index]);
  59     }
  60   }
  61 };
  62 
  63 class ShenandoahStrDedupQueueSet;
  64 
  65 typedef ShenandoahStrDedupChunkedList<64> QueueChunkedList;
  66 
  67 class ShenandoahStrDedupQueue : public CHeapObj<mtGC> {
  68 private:
  69   ShenandoahStrDedupQueueSet* _queue_set;
  70   QueueChunkedList*           _current_list;
  71   uint                        _queue_num;
  72 
  73 public:
  74   ShenandoahStrDedupQueue(ShenandoahStrDedupQueueSet* queue_set, uint num);
  75   ~ShenandoahStrDedupQueue();
  76 
  77   uint queue_num() const { return _queue_num; }
  78   inline void push(oop java_string);
  79   void oops_do(OopClosure* cl);
  80 };
  81 
  82 class ShenandoahStrDedupThread;
  83 
  84 class ShenandoahStrDedupQueueSet : public CHeapObj<mtGC> {
  85   friend class ShenandoahStrDedupQueue;
  86   friend class ShenandoahStrDedupThread;
  87 
  88 private:
  89   ShenandoahStrDedupQueue**     _local_queues;
  90   uint                          _num_queues;
  91   QueueChunkedList* volatile *  _outgoing_work_list;
  92 
  93   QueueChunkedList*   _free_list;
  94   uint                _num_free_queues;
  95 
  96   Monitor*            _lock;
  97 
  98   bool                _terminated;
  99 
 100   volatile size_t     _claimed;
 101 
 102 public:
 103   ShenandoahStrDedupQueueSet(uint n);
 104   ~ShenandoahStrDedupQueueSet();
 105 
 106   uint num_queues() const { return _num_queues; }
 107 
 108   ShenandoahStrDedupQueue* queue_at(size_t index) {
 109     assert(index < num_queues(), "Index out of bound");
 110     return _local_queues[index];
 111   }
 112 
 113   void clear_claimed() { _claimed = 0; }
 114   void parallel_cleanup();
 115   void parallel_oops_do(OopClosure* cl);
 116 
 117   // For verification only
 118   void oops_do_slow(OopClosure* cl);
 119 
 120   void terminate();
 121   bool has_terminated() {
 122     return _terminated;
 123   }
 124 
 125 private:
 126   void release_chunked_list(QueueChunkedList* l);
 127 
 128   QueueChunkedList* allocate_chunked_list();
 129   QueueChunkedList* allocate_no_lock();
 130 
 131   // Atomic publish and retrieve outgoing work list.
 132   // We don't have ABA problem, since there is only one dedup thread.
 133   QueueChunkedList* push_and_get_atomic(QueueChunkedList* q, uint queue_num);
 134   QueueChunkedList* remove_work_list_atomic(uint queue_num);
 135 
 136   Monitor* lock() const { return _lock; }
 137 
 138   size_t claim();
 139 };
 140 
 141 class ShenandoahStrDedupQueueCleanupClosure : public OopClosure {
 142 private:
 143   ShenandoahHeap*   _heap;
 144   ShenandoahMarkingContext* const _mark_context;
 145 
 146   template <class T>
 147   inline void do_oop_work(T* p);
 148 public:
 149   ShenandoahStrDedupQueueCleanupClosure() : _heap(ShenandoahHeap::heap()),
 150                                             _mark_context(ShenandoahHeap::heap()->marking_context()) {
 151   }
 152 
 153   inline void do_oop(oop* p)        { do_oop_work(p); }
 154   inline void do_oop(narrowOop* p)  { do_oop_work(p); }
 155 };
 156 
 157 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHSTRINGDEDUPQUEUE_HPP