1 /* 2 * Copyright (c) 2001, 2020, 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_GC_G1_G1CONCURRENTMARKTHREAD_HPP 26 #define SHARE_GC_G1_G1CONCURRENTMARKTHREAD_HPP 27 28 #include "gc/shared/concurrentGCThread.hpp" 29 30 class G1ConcurrentMark; 31 class G1Policy; 32 33 // The concurrent mark thread triggers the various steps of the concurrent marking 34 // cycle, including various marking cleanup. 35 class G1ConcurrentMarkThread: public ConcurrentGCThread { 36 friend class VMStructs; 37 38 double _vtime_start; // Initial virtual time. 39 double _vtime_accum; // Accumulated virtual time. 40 double _vtime_mark_accum; 41 42 G1ConcurrentMark* _cm; 43 44 enum State { 45 Idle, 46 Started, 47 InProgress 48 }; 49 50 volatile State _state; 51 52 void sleep_before_next_cycle(); 53 // Delay marking to meet MMU. 54 void delay_to_keep_mmu(G1Policy* g1_policy, bool remark); 55 double mmu_delay_end(G1Policy* g1_policy, bool remark); 56 57 void run_service(); 58 void stop_service(); 59 60 public: 61 // Constructor 62 G1ConcurrentMarkThread(G1ConcurrentMark* cm); 63 64 // Total virtual time so far for this thread and concurrent marking tasks. 65 double vtime_accum(); 66 // Marking virtual time so far this thread and concurrent marking tasks. 67 double vtime_mark_accum(); 68 69 G1ConcurrentMark* cm() { return _cm; } 70 71 void set_idle() { assert(_state != Started, "must not be starting a new cycle"); _state = Idle; } 72 bool idle() { return _state == Idle; } 73 void set_started() { assert(_state == Idle, "cycle in progress"); _state = Started; } 74 bool started() { return _state == Started; } 75 void set_in_progress() { assert(_state == Started, "must be starting a cycle"); _state = InProgress; } 76 bool in_progress() { return _state == InProgress; } 77 78 // Returns true from the moment a marking cycle is 79 // initiated (during the concurrent start pause when started() is set) 80 // to the moment when the cycle completes (just after the next 81 // marking bitmap has been cleared and in_progress() is 82 // cleared). While during_cycle() is true we will not start another cycle 83 // so that cycles do not overlap. We cannot use just in_progress() 84 // as the CM thread might take some time to wake up before noticing 85 // that started() is set and set in_progress(). 86 bool during_cycle() { return !idle(); } 87 }; 88 89 #endif // SHARE_GC_G1_G1CONCURRENTMARKTHREAD_HPP