1 /*
   2  * Copyright (c) 2001, 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
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  24 
  25 #ifndef SHARE_VM_GC_G1_SATBMARKQUEUE_HPP
  26 #define SHARE_VM_GC_G1_SATBMARKQUEUE_HPP
  27 
  28 #include "gc/g1/ptrQueue.hpp"
  29 #include "memory/allocation.hpp"
  30 
  31 class JavaThread;
  32 class SATBMarkQueueSet;
  33 
  34 // Base class for processing the contents of a SATB buffer.
  35 class SATBBufferClosure : public StackObj {
  36 protected:
  37   ~SATBBufferClosure() { }
  38 
  39 public:
  40   // Process the SATB entries in the designated buffer range.
  41   virtual void do_buffer(void** buffer, size_t size) = 0;
  42 };
  43 
  44 // A PtrQueue whose elements are (possibly stale) pointers to object heads.
  45 class SATBMarkQueue: public PtrQueue {
  46   friend class SATBMarkQueueSet;
  47 
  48 private:
  49   // Filter out unwanted entries from the buffer.
  50   void filter();
  51 
  52   template <class HeapType>
  53   void filter_impl();
  54 
  55 public:
  56   SATBMarkQueue(SATBMarkQueueSet* qset, bool permanent = false);
  57 
  58   // Process queue entries and free resources.
  59   void flush();
  60 
  61   // Apply cl to the active part of the buffer.
  62   // Prerequisite: Must be at a safepoint.
  63   void apply_closure_and_empty(SATBBufferClosure* cl);
  64 
  65   // Overrides PtrQueue::should_enqueue_buffer(). See the method's
  66   // definition for more information.
  67   virtual bool should_enqueue_buffer();
  68 
  69 #ifndef PRODUCT
  70   // Helpful for debugging
  71   void print(const char* name);
  72 #endif // PRODUCT
  73 
  74   // Compiler support.
  75   static ByteSize byte_offset_of_index() {
  76     return PtrQueue::byte_offset_of_index<SATBMarkQueue>();
  77   }
  78   using PtrQueue::byte_width_of_index;
  79 
  80   static ByteSize byte_offset_of_buf() {
  81     return PtrQueue::byte_offset_of_buf<SATBMarkQueue>();
  82   }
  83   using PtrQueue::byte_width_of_buf;
  84 
  85   static ByteSize byte_offset_of_active() {
  86     return PtrQueue::byte_offset_of_active<SATBMarkQueue>();
  87   }
  88   using PtrQueue::byte_width_of_active;
  89 
  90 };
  91 
  92 class SATBMarkQueueSet: public PtrQueueSet {
  93   SATBMarkQueue _shared_satb_queue;
  94 
  95 #ifdef ASSERT
  96   void dump_active_states(bool expected_active);
  97   void verify_active_states(bool expected_active);
  98 #endif // ASSERT
  99 
 100 public:
 101   SATBMarkQueueSet();
 102 
 103   void initialize(Monitor* cbl_mon, Mutex* fl_lock,
 104                   int process_completed_threshold,
 105                   Mutex* lock);
 106 
 107   virtual SATBMarkQueue& satb_queue_for_thread(Thread* t) = 0;
 108 
 109   // Apply "set_active(active)" to all SATB queues in the set. It should be
 110   // called only with the world stopped. The method will assert that the
 111   // SATB queues of all threads it visits, as well as the SATB queue
 112   // set itself, has an active value same as expected_active.
 113   void set_active_all_threads(bool active, bool expected_active);
 114 
 115   // Filter all the currently-active SATB buffers.
 116   void filter_thread_buffers();
 117 
 118   // If there exists some completed buffer, pop and process it, and
 119   // return true.  Otherwise return false.  Processing a buffer
 120   // consists of applying the closure to the active range of the
 121   // buffer; the leading entries may be excluded due to filtering.
 122   bool apply_closure_to_completed_buffer(SATBBufferClosure* cl);
 123 
 124 #ifndef PRODUCT
 125   // Helpful for debugging
 126   void print_all(const char* msg);
 127 #endif // PRODUCT
 128 
 129   SATBMarkQueue* shared_satb_queue() { return &_shared_satb_queue; }
 130 
 131   // If a marking is being abandoned, reset any unprocessed log buffers.
 132   void abandon_partial_marking();
 133 };
 134 
 135 class G1SATBMarkQueueSet : public SATBMarkQueueSet {
 136 public:
 137   static void handle_zero_index_for_thread(JavaThread* t);
 138   virtual SATBMarkQueue& satb_queue_for_thread(Thread* t);
 139 };
 140 
 141 #endif // SHARE_VM_GC_G1_SATBMARKQUEUE_HPP