1 /* 2 * Copyright (c) 2005, 2010, 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_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP 27 28 #include "memory/heapInspection.hpp" 29 #include "runtime/handles.hpp" 30 #include "runtime/jniHandles.hpp" 31 #include "runtime/synchronizer.hpp" 32 #include "runtime/vm_operations.hpp" 33 34 // The following class hierarchy represents 35 // a set of operations (VM_Operation) related to GC. 36 // 37 // VM_Operation 38 // VM_GC_Operation 39 // VM_GC_HeapInspection 40 // VM_GenCollectForAllocation 41 // VM_GenCollectFull 42 // VM_GenCollectFullConcurrent 43 // VM_ParallelGCFailedAllocation 44 // VM_ParallelGCFailedPermanentAllocation 45 // VM_ParallelGCSystemGC 46 // VM_GC_Operation 47 // - implements methods common to all classes in the hierarchy: 48 // prevents multiple gc requests and manages lock on heap; 49 // 50 // VM_GC_HeapInspection 51 // - prints class histogram on SIGBREAK if PrintClassHistogram 52 // is specified; and also the attach "inspectheap" operation 53 // 54 // VM_GenCollectForAllocation 55 // VM_GenCollectForPermanentAllocation 56 // VM_ParallelGCFailedAllocation 57 // VM_ParallelGCFailedPermanentAllocation 58 // - this operation is invoked when allocation is failed; 59 // operation performs garbage collection and tries to 60 // allocate afterwards; 61 // 62 // VM_GenCollectFull 63 // VM_GenCollectFullConcurrent 64 // VM_ParallelGCSystemGC 65 // - these operations preform full collection of heaps of 66 // different kind 67 // 68 69 class VM_GC_Operation: public VM_Operation { 70 protected: 71 BasicLock _pending_list_basic_lock; // for refs pending list notification (PLL) 72 unsigned int _gc_count_before; // gc count before acquiring PLL 73 unsigned int _full_gc_count_before; // full gc count before acquiring PLL 74 bool _full; // whether a "full" collection 75 bool _prologue_succeeded; // whether doit_prologue succeeded 76 GCCause::Cause _gc_cause; // the putative cause for this gc op 77 bool _gc_locked; // will be set if gc was locked 78 79 virtual bool skip_operation() const; 80 81 // java.lang.ref.Reference support 82 void acquire_pending_list_lock(); 83 void release_and_notify_pending_list_lock(); 84 85 public: 86 VM_GC_Operation(unsigned int gc_count_before, 87 unsigned int full_gc_count_before = 0, 88 bool full = false) { 89 _full = full; 90 _prologue_succeeded = false; 91 _gc_count_before = gc_count_before; 92 93 // A subclass constructor will likely overwrite the following 94 _gc_cause = GCCause::_no_cause_specified; 95 96 _gc_locked = false; 97 98 _full_gc_count_before = full_gc_count_before; 99 // In ParallelScavengeHeap::mem_allocate() collections can be 100 // executed within a loop and _all_soft_refs_clear can be set 101 // true after they have been cleared by a collection and another 102 // collection started so that _all_soft_refs_clear can be true 103 // when this collection is started. Don't assert that 104 // _all_soft_refs_clear have to be false here even though 105 // mutators have run. Soft refs will be cleared again in this 106 // collection. 107 } 108 ~VM_GC_Operation() { 109 CollectedHeap* ch = Universe::heap(); 110 ch->collector_policy()->set_all_soft_refs_clear(false); 111 } 112 113 // Acquire the reference synchronization lock 114 virtual bool doit_prologue(); 115 // Do notifyAll (if needed) and release held lock 116 virtual void doit_epilogue(); 117 118 virtual bool allow_nested_vm_operations() const { return true; } 119 bool prologue_succeeded() const { return _prologue_succeeded; } 120 121 void set_gc_locked() { _gc_locked = true; } 122 bool gc_locked() const { return _gc_locked; } 123 124 static void notify_gc_begin(bool full = false); 125 static void notify_gc_end(); 126 }; 127 128 129 class VM_GC_HeapInspection: public VM_GC_Operation { 130 private: 131 outputStream* _out; 132 bool _full_gc; 133 bool _need_prologue; 134 public: 135 VM_GC_HeapInspection(outputStream* out, bool request_full_gc, 136 bool need_prologue) : 137 VM_GC_Operation(0 /* total collections, dummy, ignored */, 138 0 /* total full collections, dummy, ignored */, 139 request_full_gc) { 140 _out = out; 141 _full_gc = request_full_gc; 142 _need_prologue = need_prologue; 143 } 144 145 ~VM_GC_HeapInspection() {} 146 virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; } 147 virtual bool skip_operation() const; 148 virtual bool doit_prologue(); 149 virtual void doit(); 150 }; 151 152 153 class VM_GenCollectForAllocation: public VM_GC_Operation { 154 private: 155 HeapWord* _res; 156 size_t _size; // size of object to be allocated. 157 bool _tlab; // alloc is of a tlab. 158 public: 159 VM_GenCollectForAllocation(size_t size, 160 bool tlab, 161 unsigned int gc_count_before) 162 : VM_GC_Operation(gc_count_before), 163 _size(size), 164 _tlab(tlab) { 165 _res = NULL; 166 } 167 ~VM_GenCollectForAllocation() {} 168 virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; } 169 virtual void doit(); 170 HeapWord* result() const { return _res; } 171 }; 172 173 174 // VM operation to invoke a collection of the heap as a 175 // GenCollectedHeap heap. 176 class VM_GenCollectFull: public VM_GC_Operation { 177 private: 178 int _max_level; 179 public: 180 VM_GenCollectFull(unsigned int gc_count_before, 181 unsigned int full_gc_count_before, 182 GCCause::Cause gc_cause, 183 int max_level) 184 : VM_GC_Operation(gc_count_before, full_gc_count_before, true /* full */), 185 _max_level(max_level) 186 { _gc_cause = gc_cause; } 187 ~VM_GenCollectFull() {} 188 virtual VMOp_Type type() const { return VMOp_GenCollectFull; } 189 virtual void doit(); 190 }; 191 192 class VM_GenCollectForPermanentAllocation: public VM_GC_Operation { 193 private: 194 HeapWord* _res; 195 size_t _size; // size of object to be allocated 196 public: 197 VM_GenCollectForPermanentAllocation(size_t size, 198 unsigned int gc_count_before, 199 unsigned int full_gc_count_before, 200 GCCause::Cause gc_cause) 201 : VM_GC_Operation(gc_count_before, full_gc_count_before, true), 202 _size(size) { 203 _res = NULL; 204 _gc_cause = gc_cause; 205 } 206 ~VM_GenCollectForPermanentAllocation() {} 207 virtual VMOp_Type type() const { return VMOp_GenCollectForPermanentAllocation; } 208 virtual void doit(); 209 HeapWord* result() const { return _res; } 210 }; 211 212 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP