1 /* 2 * Copyright (c) 2013, 2015, Red Hat, Inc. and/or its affiliates. 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_SHENANDOAHCONCURRENTTHREAD_HPP 25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHCONCURRENTTHREAD_HPP 26 27 #include "gc_implementation/shared/concurrentGCThread.hpp" 28 #include "gc_implementation/shenandoah/shenandoahHeap.hpp" 29 #include "gc_implementation/shenandoah/shenandoahSharedVariables.hpp" 30 #include "gc_interface/gcCause.hpp" 31 #include "memory/resourceArea.hpp" 32 #include "runtime/task.hpp" 33 34 class ShenandoahControlThread; 35 36 // Periodic task is useful for doing asynchronous things that do not require (heap) locks, 37 // or synchronization with other parts of collector. These could run even when ShenandoahConcurrentThread 38 // is busy driving the GC cycle. 39 class ShenandoahPeriodicTask : public PeriodicTask { 40 private: 41 ShenandoahControlThread* _thread; 42 public: 43 ShenandoahPeriodicTask(ShenandoahControlThread* thread) : 44 PeriodicTask(100), _thread(thread) {} 45 virtual void task(); 46 }; 47 48 class ShenandoahControlThread: public ConcurrentGCThread { 49 friend class VMStructs; 50 51 private: 52 typedef enum { 53 none, 54 concurrent_normal, 55 stw_degenerated, 56 stw_full, 57 } GCMode; 58 59 // While we could have a single lock for these, it may risk unblocking 60 // explicit GC waiters when alloc failure GC cycle finishes. We want instead 61 // to make complete explicit cycle for for demanding customers. 62 Monitor _alloc_failure_waiters_lock; 63 Monitor _explicit_gc_waiters_lock; 64 ShenandoahPeriodicTask _periodic_task; 65 66 private: 67 static SurrogateLockerThread* _slt; 68 69 public: 70 void run(); 71 void stop(); 72 73 private: 74 ShenandoahSharedFlag _explicit_gc; 75 ShenandoahSharedFlag _alloc_failure_gc; 76 ShenandoahSharedFlag _graceful_shutdown; 77 ShenandoahSharedFlag _heap_changed; 78 ShenandoahSharedFlag _do_counters_update; 79 ShenandoahSharedFlag _force_counters_update; 80 volatile intptr_t _allocs_seen; 81 GCCause::Cause _explicit_gc_cause; 82 ShenandoahHeap::ShenandoahDegenPoint _degen_point; 83 84 bool check_cancellation_or_degen(ShenandoahHeap::ShenandoahDegenPoint point); 85 void service_concurrent_normal_cycle(GCCause::Cause cause); 86 void service_stw_full_cycle(GCCause::Cause cause); 87 void service_stw_degenerated_cycle(GCCause::Cause cause, ShenandoahHeap::ShenandoahDegenPoint point); 88 89 bool try_set_alloc_failure_gc(); 90 void notify_alloc_failure_waiters(); 91 bool is_alloc_failure_gc(); 92 93 void notify_explicit_gc_waiters(); 94 95 public: 96 // Constructor 97 ShenandoahControlThread(); 98 ~ShenandoahControlThread(); 99 100 static void makeSurrogateLockerThread(TRAPS); 101 static SurrogateLockerThread* slt() { return _slt; } 102 103 // Handle allocation failure from normal allocation. 104 // Blocks until memory is available. 105 void handle_alloc_failure(size_t words); 106 107 // Handle allocation failure from evacuation path. 108 // Optionally blocks while collector is handling the failure. 109 void handle_alloc_failure_evac(size_t words); 110 111 // Handle explicit GC request. 112 // Blocks until GC is over. 113 void handle_explicit_gc(GCCause::Cause cause); 114 115 void handle_counters_update(); 116 void handle_force_counters_update(); 117 void set_forced_counters_update(bool value); 118 119 void notify_heap_changed(); 120 121 void pacing_notify_alloc(size_t words); 122 123 void start(); 124 void prepare_for_graceful_shutdown(); 125 bool in_graceful_shutdown(); 126 127 char* name() const { return (char*)"ShenandoahConcurrentThread";} 128 129 // Printing 130 void print_on(outputStream* st) const; 131 void print() const; 132 133 }; 134 135 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHCONCURRENTTHREAD_HPP