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/shared/stringdedup/stringDedup.hpp"
  28 #include "gc/shenandoah/shenandoahHeap.hpp"
  29 #include "oops/oop.hpp"
  30 
  31 template <uint buffer_size>
  32 class ShenandoahOopBuffer : public CHeapObj<mtGC> {
  33 private:
  34   oop   _buf[buffer_size];
  35   uint  _index;
  36   ShenandoahOopBuffer<buffer_size>* _next;
  37 
  38 public:
  39   ShenandoahOopBuffer();
  40 
  41   bool is_full()  const;
  42   bool is_empty() const;
  43   uint size()     const;
  44 
  45   void push(oop obj);
  46   oop pop();
  47 
  48   void reset();
  49 
  50   void set_next(ShenandoahOopBuffer<buffer_size>* next);
  51   ShenandoahOopBuffer<buffer_size>* next() const;
  52 
  53   void unlink_or_oops_do(StringDedupUnlinkOrOopsDoClosure* cl);
  54   void oops_do(OopClosure* cl);
  55 };
  56 
  57 typedef ShenandoahOopBuffer<64> ShenandoahQueueBuffer;
  58 
  59 // Muti-producer and single consumer queue set
  60 class ShenandoahStrDedupQueue : public StringDedupQueue {
  61 private:
  62   ShenandoahQueueBuffer** _producer_queues;
  63   ShenandoahQueueBuffer*  _consumer_queue;
  64   size_t                  _num_producer_queue;
  65 
  66   // The queue is used for producers to publish completed buffers
  67   ShenandoahQueueBuffer* _published_queues;
  68 
  69   // Cached free buffers
  70   ShenandoahQueueBuffer* _free_list;
  71   size_t                 _num_free_buffer;
  72   const size_t           _max_free_buffer;
  73 
  74   bool                   _cancel;
  75 
  76   // statistics
  77   size_t                 _total_buffers;
  78 
  79 private:
  80   ~ShenandoahStrDedupQueue();
  81 
  82 public:
  83   ShenandoahStrDedupQueue();
  84 
  85   void wait_impl();
  86   void cancel_wait_impl();
  87 
  88   void push_impl(uint worker_id, oop string_oop);
  89   oop  pop_impl();
  90 
  91   void unlink_or_oops_do_impl(StringDedupUnlinkOrOopsDoClosure* cl, size_t queue);
  92 
  93   void print_statistics_impl();
  94   void verify_impl();
  95 
  96 protected:
  97   size_t num_queues() const { return (_num_producer_queue + 2); }
  98 
  99 private:
 100   ShenandoahQueueBuffer* new_buffer();
 101 
 102   void release_buffers(ShenandoahQueueBuffer* list);
 103 
 104   ShenandoahQueueBuffer* queue_at(size_t queue_id) const;
 105 
 106   bool pop_candidate(oop& obj);
 107 
 108   void set_producer_buffer(ShenandoahQueueBuffer* buf, size_t queue_id);
 109 
 110   void verify(ShenandoahQueueBuffer* head);
 111 };
 112 
 113 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHSTRINGDEDUPQUEUE_HPP