1 /*

     2  * Copyright (c) 2001, 2017, 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 #ifndef SHARE_VM_GC_G1_CONCURRENTMARKTHREAD_HPP

    26 #define SHARE_VM_GC_G1_CONCURRENTMARKTHREAD_HPP

    27 

    28 #include "gc/shared/concurrentGCPhaseManager.hpp"

    29 #include "gc/shared/concurrentGCThread.hpp"

    30 

    31 // The Concurrent Mark GC Thread triggers the parallel G1CMConcurrentMarkingTasks

    32 // as well as handling various marking cleanup.

    33 

    34 class G1ConcurrentMark;

    35 class G1Policy;

    36 

    37 class ConcurrentMarkThread: public ConcurrentGCThread {

    38   friend class VMStructs;

    39 

    40   double _vtime_start;  // Initial virtual time.

    41   double _vtime_accum;  // Accumulated virtual time.

    42   double _vtime_mark_accum;

    43 

    44   G1ConcurrentMark*                _cm;

    45 

    46   enum State {

    47     Idle,

    48     Started,

    49     InProgress

    50   };

    51 

    52   volatile State _state;

    53 

    54   // WhiteBox testing support.

    55   ConcurrentGCPhaseManager::Stack _phase_manager_stack;

    56 

    57   void sleepBeforeNextCycle();

    58   // Delay marking to meet MMU.

    59   void delay_to_keep_mmu(G1Policy* g1_policy, bool remark);

    60   double mmu_sleep_time(G1Policy* g1_policy, bool remark);

    61 

    62   void run_service();

    63   void stop_service();

    64 

    65  public:

    66   // Constructor

    67   ConcurrentMarkThread(G1ConcurrentMark* cm);

    68 

    69   // Total virtual time so far for this thread and concurrent marking tasks.

    70   double vtime_accum();

    71   // Marking virtual time so far this thread and concurrent marking tasks.

    72   double vtime_mark_accum();

    73 

    74   G1ConcurrentMark* cm()   { return _cm; }

    75 

    76   void set_idle()          { assert(_state != Started, "must not be starting a new cycle"); _state = Idle; }

    77   bool idle()              { return _state == Idle; }

    78   void set_started()       { assert(_state == Idle, "cycle in progress"); _state = Started; }

    79   bool started()           { return _state == Started; }

    80   void set_in_progress()   { assert(_state == Started, "must be starting a cycle"); _state = InProgress; }

    81   bool in_progress()       { return _state == InProgress; }

    82 

    83   // Returns true from the moment a marking cycle is

    84   // initiated (during the initial-mark pause when started() is set)

    85   // to the moment when the cycle completes (just after the next

    86   // marking bitmap has been cleared and in_progress() is

    87   // cleared). While during_cycle() is true we will not start another cycle

    88   // so that cycles do not overlap. We cannot use just in_progress()

    89   // as the CM thread might take some time to wake up before noticing

    90   // that started() is set and set in_progress().

    91   bool during_cycle()      { return !idle(); }

    92 

    93   // WhiteBox testing support.

    94   const char* const* concurrent_phases() const;

    95   bool request_concurrent_phase(const char* phase);

    96 

    97   ConcurrentGCPhaseManager::Stack* phase_manager_stack() {

    98     return &_phase_manager_stack;

    99   }

   100 };

   101 

   102 #endif // SHARE_VM_GC_G1_CONCURRENTMARKTHREAD_HPP