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 #include "prims/jvmtiExport.hpp" 34 35 // The following class hierarchy represents 36 // a set of operations (VM_Operation) related to GC. 37 // 38 // VM_Operation 39 // VM_GC_Operation 40 // VM_GC_HeapInspection 41 // VM_GenCollectForAllocation 42 // VM_GenCollectFull 43 // VM_GenCollectFullConcurrent 44 // VM_ParallelGCFailedAllocation 45 // VM_ParallelGCFailedPermanentAllocation 46 // VM_ParallelGCSystemGC 47 // VM_GC_Operation 48 // - implements methods common to all classes in the hierarchy: 49 // prevents multiple gc requests and manages lock on heap; 50 // 51 // VM_GC_HeapInspection 52 // - prints class histogram on SIGBREAK if PrintClassHistogram 53 // is specified; and also the attach "inspectheap" operation 54 // 55 // VM_GenCollectForAllocation 56 // VM_GenCollectForPermanentAllocation 57 // VM_ParallelGCFailedAllocation 58 // VM_ParallelGCFailedPermanentAllocation 59 // - this operation is invoked when allocation is failed; 60 // operation performs garbage collection and tries to 61 // allocate afterwards; 62 // 63 // VM_GenCollectFull 64 // VM_GenCollectFullConcurrent 65 // VM_ParallelGCSystemGC 66 // - these operations preform full collection of heaps of 67 // different kind 68 // 69 70 class VM_GC_Operation: public VM_Operation { 71 protected: 72 BasicLock _pending_list_basic_lock; // for refs pending list notification (PLL) 73 unsigned int _gc_count_before; // gc count before acquiring PLL 74 unsigned int _full_gc_count_before; // full gc count before acquiring PLL 75 bool _full; // whether a "full" collection 76 bool _prologue_succeeded; // whether doit_prologue succeeded 77 GCCause::Cause _gc_cause; // the putative cause for this gc op 78 bool _gc_locked; // will be set if gc was locked 79 80 virtual bool skip_operation() const; 81 82 // java.lang.ref.Reference support 83 void acquire_pending_list_lock(); 84 void release_and_notify_pending_list_lock(); 85 86 public: 87 VM_GC_Operation(unsigned int gc_count_before, 88 unsigned int full_gc_count_before = 0, 89 bool full = false) { 90 _full = full; 91 _prologue_succeeded = false; 92 _gc_count_before = gc_count_before; 93 94 // A subclass constructor will likely overwrite the following 95 _gc_cause = GCCause::_no_cause_specified; 96 97 _gc_locked = false; 98 99 _full_gc_count_before = full_gc_count_before; 100 // In ParallelScavengeHeap::mem_allocate() collections can be 101 // executed within a loop and _all_soft_refs_clear can be set 102 // true after they have been cleared by a collection and another 103 // collection started so that _all_soft_refs_clear can be true 104 // when this collection is started. Don't assert that 105 // _all_soft_refs_clear have to be false here even though 106 // mutators have run. Soft refs will be cleared again in this 107 // collection. 108 } 109 ~VM_GC_Operation() { 110 CollectedHeap* ch = Universe::heap(); 111 ch->collector_policy()->set_all_soft_refs_clear(false); 112 } 113 114 // Acquire the reference synchronization lock 115 virtual bool doit_prologue(); 116 // Do notifyAll (if needed) and release held lock 117 virtual void doit_epilogue(); 118 119 virtual bool allow_nested_vm_operations() const { return true; } 120 bool prologue_succeeded() const { return _prologue_succeeded; } 121 122 void set_gc_locked() { _gc_locked = true; } 123 bool gc_locked() const { return _gc_locked; } 124 125 static void notify_gc_begin(bool full = false); 126 static void notify_gc_end(); 127 }; 128 129 130 class VM_GC_HeapInspection: public VM_GC_Operation { 131 private: 132 outputStream* _out; 133 bool _full_gc; 134 bool _need_prologue; 135 public: 136 VM_GC_HeapInspection(outputStream* out, bool request_full_gc, 137 bool need_prologue) : 138 VM_GC_Operation(0 /* total collections, dummy, ignored */, 139 0 /* total full collections, dummy, ignored */, 140 request_full_gc) { 141 _out = out; 142 _full_gc = request_full_gc; 143 _need_prologue = need_prologue; 144 } 145 146 ~VM_GC_HeapInspection() {} 147 virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; } 148 virtual bool skip_operation() const; 149 virtual bool doit_prologue(); 150 virtual void doit(); 151 }; 152 153 154 class VM_GenCollectForAllocation: public VM_GC_Operation { 155 private: 156 HeapWord* _res; 157 size_t _size; // size of object to be allocated. 158 bool _tlab; // alloc is of a tlab. 159 public: 160 VM_GenCollectForAllocation(size_t size, 161 bool tlab, 162 unsigned int gc_count_before) 163 : VM_GC_Operation(gc_count_before), 164 _size(size), 165 _tlab(tlab) { 166 _res = NULL; 167 } 168 ~VM_GenCollectForAllocation() {} 169 virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; } 170 virtual void doit(); 171 HeapWord* result() const { return _res; } 172 }; 173 174 175 // VM operation to invoke a collection of the heap as a 176 // GenCollectedHeap heap. 177 class VM_GenCollectFull: public VM_GC_Operation { 178 private: 179 int _max_level; 180 public: 181 VM_GenCollectFull(unsigned int gc_count_before, 182 unsigned int full_gc_count_before, 183 GCCause::Cause gc_cause, 184 int max_level) 185 : VM_GC_Operation(gc_count_before, full_gc_count_before, true /* full */), 186 _max_level(max_level) 187 { _gc_cause = gc_cause; } 188 ~VM_GenCollectFull() {} 189 virtual VMOp_Type type() const { return VMOp_GenCollectFull; } 190 virtual void doit(); 191 }; 192 193 class VM_GenCollectForPermanentAllocation: public VM_GC_Operation { 194 private: 195 HeapWord* _res; 196 size_t _size; // size of object to be allocated 197 public: 198 VM_GenCollectForPermanentAllocation(size_t size, 199 unsigned int gc_count_before, 200 unsigned int full_gc_count_before, 201 GCCause::Cause gc_cause) 202 : VM_GC_Operation(gc_count_before, full_gc_count_before, true), 203 _size(size) { 204 _res = NULL; 205 _gc_cause = gc_cause; 206 } 207 ~VM_GenCollectForPermanentAllocation() {} 208 virtual VMOp_Type type() const { return VMOp_GenCollectForPermanentAllocation; } 209 virtual void doit(); 210 HeapWord* result() const { return _res; } 211 }; 212 213 class SvcGCMarker : public StackObj { 214 private: 215 JvmtiGCMarker _jgcm; 216 public: 217 typedef enum { MINOR, FULL, OTHER } reason_type; 218 219 SvcGCMarker(reason_type reason ) { 220 VM_GC_Operation::notify_gc_begin(reason == FULL); 221 } 222 223 ~SvcGCMarker() { 224 VM_GC_Operation::notify_gc_end(); 225 } 226 }; 227 228 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP