1 /* 2 * Copyright (c) 2021, Amazon.com, Inc. 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 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHREGULATORTHREAD_HPP 25 #define SHARE_GC_SHENANDOAH_SHENANDOAHREGULATORTHREAD_HPP 26 27 #include "gc/shared/concurrentGCThread.hpp" 28 #include "gc/shared/gcCause.hpp" 29 #include "gc/shenandoah/shenandoahSharedVariables.hpp" 30 #include "runtime/mutex.hpp" 31 32 class ShenandoahHeuristics; 33 class ShenandoahControlThread; 34 35 /* 36 * The purpose of this class (and thread) is to allow us to continue 37 * to evaluate heuristics during a garbage collection. This is necessary 38 * to allow young generation collections to interrupt and old generation 39 * collection which is in-progress. This puts heuristic triggers on the 40 * same footing as other gc requests (alloc failure, System.gc, etc.). 41 * However, this regulator does not block after submitting a gc request. 42 * 43 * We could use a PeriodicTask for this, but this thread will sleep longer 44 * when the allocation rate is lower and PeriodicTasks cannot adjust their 45 * sleep time. 46 */ 47 class ShenandoahRegulatorThread: public ConcurrentGCThread { 48 friend class VMStructs; 49 50 public: 51 explicit ShenandoahRegulatorThread(ShenandoahControlThread* control_thread); 52 53 const char* name() const { return "ShenandoahRegulatorThread";} 54 55 // This is called from allocation path, and thus should be fast. 56 void notify_heap_changed() { 57 // Notify that something had changed. 58 if (_heap_changed.is_unset()) { 59 _heap_changed.set(); 60 } 61 } 62 63 protected: 64 void run_service(); 65 void stop_service(); 66 67 private: 68 void regulate_interleaved_cycles(); 69 void regulate_concurrent_cycles(); 70 void regulate_heap(); 71 72 bool start_old_cycle(); 73 bool start_young_cycle(); 74 bool start_global_cycle(); 75 76 bool should_unload_classes(); 77 78 ShenandoahSharedFlag _heap_changed; 79 ShenandoahControlThread* _control_thread; 80 ShenandoahHeuristics* _young_heuristics; 81 ShenandoahHeuristics* _old_heuristics; 82 ShenandoahHeuristics* _global_heuristics; 83 84 int _sleep; 85 double _last_sleep_adjust_time; 86 87 void regulator_sleep(); 88 }; 89 90 91 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHREGULATORTHREAD_HPP