1 /* 2 * Copyright (c) 2005, 2019, 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_GC_SHARED_GCVMOPERATIONS_HPP 26 #define SHARE_GC_SHARED_GCVMOPERATIONS_HPP 27 28 #include "gc/shared/collectedHeap.hpp" 29 #include "gc/shared/genCollectedHeap.hpp" 30 #include "memory/heapInspection.hpp" 31 #include "memory/metaspace/metaspaceEnums.hpp" 32 #include "prims/jvmtiExport.hpp" 33 #include "runtime/handles.hpp" 34 #include "runtime/jniHandles.hpp" 35 #include "runtime/synchronizer.hpp" 36 #include "runtime/vmOperations.hpp" 37 38 // The following class hierarchy represents 39 // a set of operations (VM_Operation) related to GC. 40 // 41 // VM_Operation 42 // VM_GC_Operation 43 // VM_GC_HeapInspection 44 // VM_GenCollectFull 45 // VM_GenCollectFullConcurrent 46 // VM_ParallelGCSystemGC 47 // VM_CollectForAllocation 48 // VM_GenCollectForAllocation 49 // VM_ParallelGCFailedAllocation 50 // VM_GC_Operation 51 // - implements methods common to all classes in the hierarchy: 52 // prevents multiple gc requests and manages lock on heap; 53 // 54 // VM_GC_HeapInspection 55 // - prints class histogram on SIGBREAK if PrintClassHistogram 56 // is specified; and also the attach "inspectheap" operation 57 // 58 // VM_CollectForAllocation 59 // VM_GenCollectForAllocation 60 // VM_ParallelGCFailedAllocation 61 // - this operation is invoked when allocation is failed; 62 // operation performs garbage collection and tries to 63 // allocate afterwards; 64 // 65 // VM_GenCollectFull 66 // VM_GenCollectFullConcurrent 67 // VM_ParallelGCSystemGC 68 // - these operations preform full collection of heaps of 69 // different kind 70 // 71 72 class VM_GC_Operation: public VM_Operation { 73 protected: 74 uint _gc_count_before; // gc count before acquiring PLL 75 uint _full_gc_count_before; // full gc count before acquiring PLL 76 bool _full; // whether a "full" collection 77 bool _prologue_succeeded; // whether doit_prologue succeeded 78 GCCause::Cause _gc_cause; // the putative cause for this gc op 79 bool _gc_locked; // will be set if gc was locked 80 81 virtual bool skip_operation() const; 82 83 public: 84 VM_GC_Operation(uint gc_count_before, 85 GCCause::Cause _cause, 86 uint full_gc_count_before = 0, 87 bool full = false) { 88 _full = full; 89 _prologue_succeeded = false; 90 _gc_count_before = gc_count_before; 91 92 // A subclass constructor will likely overwrite the following 93 _gc_cause = _cause; 94 95 _gc_locked = false; 96 97 _full_gc_count_before = full_gc_count_before; 98 // In ParallelScavengeHeap::mem_allocate() collections can be 99 // executed within a loop and _all_soft_refs_clear can be set 100 // true after they have been cleared by a collection and another 101 // collection started so that _all_soft_refs_clear can be true 102 // when this collection is started. Don't assert that 103 // _all_soft_refs_clear have to be false here even though 104 // mutators have run. Soft refs will be cleared again in this 105 // collection. 106 } 107 ~VM_GC_Operation(); 108 109 // Acquire the reference synchronization lock 110 virtual bool doit_prologue(); 111 // Do notifyAll (if needed) and release held lock 112 virtual void doit_epilogue(); 113 114 virtual bool allow_nested_vm_operations() const { return true; } 115 bool prologue_succeeded() const { return _prologue_succeeded; } 116 117 void set_gc_locked() { _gc_locked = true; } 118 bool gc_locked() const { return _gc_locked; } 119 120 static void notify_gc_begin(bool full = false); 121 static void notify_gc_end(); 122 }; 123 124 125 class VM_GC_HeapInspection: public VM_GC_Operation { 126 private: 127 outputStream* _out; 128 bool _full_gc; 129 bool _csv_format; // "comma separated values" format for spreadsheet. 130 bool _print_help; 131 bool _print_class_stats; 132 const char* _columns; 133 public: 134 VM_GC_HeapInspection(outputStream* out, bool request_full_gc) : 135 VM_GC_Operation(0 /* total collections, dummy, ignored */, 136 GCCause::_heap_inspection /* GC Cause */, 137 0 /* total full collections, dummy, ignored */, 138 request_full_gc) { 139 _out = out; 140 _full_gc = request_full_gc; 141 _csv_format = false; 142 _print_help = false; 143 _print_class_stats = false; 144 _columns = NULL; 145 } 146 147 ~VM_GC_HeapInspection() {} 148 virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; } 149 virtual bool skip_operation() const; 150 virtual void doit(); 151 void set_csv_format(bool value) {_csv_format = value;} 152 void set_print_help(bool value) {_print_help = value;} 153 void set_print_class_stats(bool value) {_print_class_stats = value;} 154 void set_columns(const char* value) {_columns = value;} 155 protected: 156 bool collect(); 157 }; 158 159 class VM_CollectForAllocation : public VM_GC_Operation { 160 protected: 161 size_t _word_size; // Size of object to be allocated (in number of words) 162 HeapWord* _result; // Allocation result (NULL if allocation failed) 163 164 public: 165 VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause); 166 167 HeapWord* result() const { 168 return _result; 169 } 170 }; 171 172 class VM_GenCollectForAllocation : public VM_CollectForAllocation { 173 private: 174 bool _tlab; // alloc is of a tlab. 175 public: 176 VM_GenCollectForAllocation(size_t word_size, 177 bool tlab, 178 uint gc_count_before) 179 : VM_CollectForAllocation(word_size, gc_count_before, GCCause::_allocation_failure), 180 _tlab(tlab) { 181 assert(word_size != 0, "An allocation should always be requested with this operation."); 182 } 183 ~VM_GenCollectForAllocation() {} 184 virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; } 185 virtual void doit(); 186 }; 187 188 // VM operation to invoke a collection of the heap as a 189 // GenCollectedHeap heap. 190 class VM_GenCollectFull: public VM_GC_Operation { 191 private: 192 GenCollectedHeap::GenerationType _max_generation; 193 public: 194 VM_GenCollectFull(uint gc_count_before, 195 uint full_gc_count_before, 196 GCCause::Cause gc_cause, 197 GenCollectedHeap::GenerationType max_generation) 198 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true /* full */), 199 _max_generation(max_generation) { } 200 ~VM_GenCollectFull() {} 201 virtual VMOp_Type type() const { return VMOp_GenCollectFull; } 202 virtual void doit(); 203 }; 204 205 class VM_CollectForMetadataAllocation: public VM_GC_Operation { 206 private: 207 MetaWord* _result; 208 size_t _size; // size of object to be allocated 209 metaspace::MetadataType _mdtype; 210 ClassLoaderData* _loader_data; 211 212 public: 213 VM_CollectForMetadataAllocation(ClassLoaderData* loader_data, 214 size_t size, 215 metaspace::MetadataType mdtype, 216 uint gc_count_before, 217 uint full_gc_count_before, 218 GCCause::Cause gc_cause); 219 220 virtual VMOp_Type type() const { return VMOp_CollectForMetadataAllocation; } 221 virtual void doit(); 222 MetaWord* result() const { return _result; } 223 224 bool initiate_concurrent_GC(); 225 }; 226 227 class SvcGCMarker : public StackObj { 228 private: 229 JvmtiGCMarker _jgcm; 230 public: 231 typedef enum { MINOR, FULL, CONCURRENT } reason_type; 232 233 SvcGCMarker(reason_type reason ) { 234 VM_GC_Operation::notify_gc_begin(reason == FULL); 235 } 236 237 ~SvcGCMarker() { 238 VM_GC_Operation::notify_gc_end(); 239 } 240 }; 241 242 #endif // SHARE_GC_SHARED_GCVMOPERATIONS_HPP