1 /* 2 * Copyright (c) 2005, 2020, 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.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 public: 130 VM_GC_HeapInspection(outputStream* out, bool request_full_gc) : 131 VM_GC_Operation(0 /* total collections, dummy, ignored */, 132 GCCause::_heap_inspection /* GC Cause */, 133 0 /* total full collections, dummy, ignored */, 134 request_full_gc), _out(out), _full_gc(request_full_gc) {} 135 136 ~VM_GC_HeapInspection() {} 137 virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; } 138 virtual bool skip_operation() const; 139 virtual void doit(); 140 protected: 141 bool collect(); 142 }; 143 144 class VM_CollectForAllocation : public VM_GC_Operation { 145 protected: 146 size_t _word_size; // Size of object to be allocated (in number of words) 147 HeapWord* _result; // Allocation result (NULL if allocation failed) 148 149 public: 150 VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause); 151 152 HeapWord* result() const { 153 return _result; 154 } 155 }; 156 157 class VM_GenCollectForAllocation : public VM_CollectForAllocation { 158 private: 159 bool _tlab; // alloc is of a tlab. 160 public: 161 VM_GenCollectForAllocation(size_t word_size, 162 bool tlab, 163 uint gc_count_before) 164 : VM_CollectForAllocation(word_size, gc_count_before, GCCause::_allocation_failure), 165 _tlab(tlab) { 166 assert(word_size != 0, "An allocation should always be requested with this operation."); 167 } 168 ~VM_GenCollectForAllocation() {} 169 virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; } 170 virtual void doit(); 171 }; 172 173 // VM operation to invoke a collection of the heap as a 174 // GenCollectedHeap heap. 175 class VM_GenCollectFull: public VM_GC_Operation { 176 private: 177 GenCollectedHeap::GenerationType _max_generation; 178 public: 179 VM_GenCollectFull(uint gc_count_before, 180 uint full_gc_count_before, 181 GCCause::Cause gc_cause, 182 GenCollectedHeap::GenerationType max_generation) 183 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, 184 max_generation != GenCollectedHeap::YoungGen /* full */), 185 _max_generation(max_generation) { } 186 ~VM_GenCollectFull() {} 187 virtual VMOp_Type type() const { return VMOp_GenCollectFull; } 188 virtual void doit(); 189 }; 190 191 class VM_CollectForMetadataAllocation: public VM_GC_Operation { 192 private: 193 MetaWord* _result; 194 size_t _size; // size of object to be allocated 195 Metaspace::MetadataType _mdtype; 196 ClassLoaderData* _loader_data; 197 198 public: 199 VM_CollectForMetadataAllocation(ClassLoaderData* loader_data, 200 size_t size, 201 Metaspace::MetadataType mdtype, 202 uint gc_count_before, 203 uint full_gc_count_before, 204 GCCause::Cause gc_cause); 205 206 virtual VMOp_Type type() const { return VMOp_CollectForMetadataAllocation; } 207 virtual void doit(); 208 MetaWord* result() const { return _result; } 209 210 bool initiate_concurrent_GC(); 211 }; 212 213 class SvcGCMarker : public StackObj { 214 private: 215 JvmtiGCMarker _jgcm; 216 public: 217 typedef enum { MINOR, FULL, CONCURRENT } 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_GC_SHARED_GCVMOPERATIONS_HPP