1 /* 2 * Copyright (c) 2013, 2018, Red Hat, Inc. All rights reserved. 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_SHENANDOAHSCHEDULERTHREAD_HPP 25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHSCHEDULERTHREAD_HPP 26 27 #include "gc/shared/gcCause.hpp" 28 #include "gc/shared/concurrentGCThread.hpp" 29 #include "gc/shenandoah/shenandoahHeap.hpp" 30 #include "gc/shenandoah/shenandoahSharedVariables.hpp" 31 #include "runtime/task.hpp" 32 #include "utilities/ostream.hpp" 33 34 // Periodic task is useful for doing asynchronous things that do not require (heap) locks, 35 // or synchronization with other parts of collector. These could run even when ShenandoahConcurrentThread 36 // is busy driving the GC cycle. 37 class ShenandoahPeriodicTask : public PeriodicTask { 38 private: 39 ShenandoahControlThread* _thread; 40 public: 41 ShenandoahPeriodicTask(ShenandoahControlThread* thread) : 42 PeriodicTask(100), _thread(thread) {} 43 virtual void task(); 44 }; 45 46 // Periodic task to flush SATB buffers periodically. 47 class ShenandoahPeriodicSATBFlushTask : public PeriodicTask { 48 public: 49 ShenandoahPeriodicSATBFlushTask() : PeriodicTask(ShenandoahSATBBufferFlushInterval) {} 50 virtual void task(); 51 }; 52 53 class ShenandoahControlThread: public ConcurrentGCThread { 54 friend class VMStructs; 55 56 private: 57 typedef enum { 58 none, 59 concurrent_traversal, 60 concurrent_normal, 61 stw_degenerated, 62 stw_full, 63 } GCMode; 64 65 // While we could have a single lock for these, it may risk unblocking 66 // GC waiters when alloc failure GC cycle finishes. We want instead 67 // to make complete explicit cycle for for demanding customers. 68 Monitor _alloc_failure_waiters_lock; 69 Monitor _gc_waiters_lock; 70 ShenandoahPeriodicTask _periodic_task; 71 ShenandoahPeriodicSATBFlushTask _periodic_satb_flush_task; 72 73 public: 74 void run_service(); 75 void stop_service(); 76 77 private: 78 ShenandoahSharedFlag _gc_requested; 79 ShenandoahSharedFlag _alloc_failure_gc; 80 ShenandoahSharedFlag _graceful_shutdown; 81 ShenandoahSharedFlag _heap_changed; 82 ShenandoahSharedFlag _do_counters_update; 83 ShenandoahSharedFlag _force_counters_update; 84 GCCause::Cause _requested_gc_cause; 85 ShenandoahHeap::ShenandoahDegenPoint _degen_point; 86 87 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t)); 88 volatile size_t _allocs_seen; 89 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0); 90 91 bool check_cancellation_or_degen(ShenandoahHeap::ShenandoahDegenPoint point); 92 void service_concurrent_normal_cycle(GCCause::Cause cause); 93 void service_stw_full_cycle(GCCause::Cause cause); 94 void service_stw_degenerated_cycle(GCCause::Cause cause, ShenandoahHeap::ShenandoahDegenPoint point); 95 void service_concurrent_traversal_cycle(GCCause::Cause cause); 96 void service_uncommit(double shrink_before); 97 98 bool try_set_alloc_failure_gc(); 99 void notify_alloc_failure_waiters(); 100 bool is_alloc_failure_gc(); 101 102 void notify_gc_waiters(); 103 104 // Handle GC request. 105 // Blocks until GC is over. 106 void handle_requested_gc(GCCause::Cause cause); 107 108 bool is_explicit_gc(GCCause::Cause cause) const; 109 public: 110 // Constructor 111 ShenandoahControlThread(); 112 ~ShenandoahControlThread(); 113 114 // Handle allocation failure from normal allocation. 115 // Blocks until memory is available. 116 void handle_alloc_failure(size_t words); 117 118 // Handle allocation failure from evacuation path. 119 // Optionally blocks while collector is handling the failure. 120 void handle_alloc_failure_evac(size_t words); 121 122 void request_gc(GCCause::Cause cause); 123 124 void handle_counters_update(); 125 void handle_force_counters_update(); 126 void set_forced_counters_update(bool value); 127 128 void notify_heap_changed(); 129 130 void pacing_notify_alloc(size_t words); 131 132 void start(); 133 void prepare_for_graceful_shutdown(); 134 bool in_graceful_shutdown(); 135 136 char* name() const { return (char*)"ShenandoahControlThread";} 137 138 // Printing 139 void print_on(outputStream* st) const; 140 void print() const; 141 }; 142 143 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHSCHEDULERTHREAD_HPP