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 "prims/jvmtiExport.hpp" 32 #include "runtime/handles.hpp" 33 #include "runtime/jniHandles.hpp" 34 #include "runtime/synchronizer.hpp" 35 #include "runtime/vmOperations.hpp" 36 37 // The following class hierarchy represents 38 // a set of operations (VM_Operation) related to GC. 39 // 40 // VM_Operation 41 // VM_GC_Operation 42 // VM_GC_HeapInspection 43 // VM_GenCollectFull 44 // VM_GenCollectFullConcurrent 45 // VM_ParallelGCSystemGC 46 // VM_CollectForAllocation 47 // VM_GenCollectForAllocation 48 // VM_ParallelGCFailedAllocation 49 // VM_GC_Operation 50 // - implements methods common to all classes in the hierarchy: 51 // prevents multiple gc requests and manages lock on heap; 52 // 53 // VM_GC_HeapInspection 54 // - prints class histogram on SIGBREAK if PrintClassHistogram 55 // is specified; and also the attach "inspectheap" operation 56 // 57 // VM_CollectForAllocation 58 // VM_GenCollectForAllocation 59 // VM_ParallelGCFailedAllocation 60 // - this operation is invoked when allocation is failed; 61 // operation performs garbage collection and tries to 62 // allocate afterwards; 63 // 64 // VM_GenCollectFull 65 // VM_GenCollectFullConcurrent 66 // VM_ParallelGCSystemGC 67 // - these operations preform full collection of heaps of 68 // different kind 69 // 70 71 class VM_GC_Operation: public VM_Operation { 72 protected: 73 uint _gc_count_before; // gc count before acquiring PLL 74 uint _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 public: VM_GC_Operation(uint gc_count_before,GCCause::Cause _cause,uint full_gc_count_before=0,bool full=false)83 VM_GC_Operation(uint gc_count_before, 84 GCCause::Cause _cause, 85 uint full_gc_count_before = 0, 86 bool full = false) { 87 _full = full; 88 _prologue_succeeded = false; 89 _gc_count_before = gc_count_before; 90 91 // A subclass constructor will likely overwrite the following 92 _gc_cause = _cause; 93 94 _gc_locked = false; 95 96 _full_gc_count_before = full_gc_count_before; 97 // In ParallelScavengeHeap::mem_allocate() collections can be 98 // executed within a loop and _all_soft_refs_clear can be set 99 // true after they have been cleared by a collection and another 100 // collection started so that _all_soft_refs_clear can be true 101 // when this collection is started. Don't assert that 102 // _all_soft_refs_clear have to be false here even though 103 // mutators have run. Soft refs will be cleared again in this 104 // collection. 105 } 106 ~VM_GC_Operation(); 107 108 // Acquire the reference synchronization lock 109 virtual bool doit_prologue(); 110 // Do notifyAll (if needed) and release held lock 111 virtual void doit_epilogue(); 112 allow_nested_vm_operations() const113 virtual bool allow_nested_vm_operations() const { return true; } prologue_succeeded() const114 bool prologue_succeeded() const { return _prologue_succeeded; } 115 set_gc_locked()116 void set_gc_locked() { _gc_locked = true; } gc_locked() const117 bool gc_locked() const { return _gc_locked; } 118 119 static void notify_gc_begin(bool full = false); 120 static void notify_gc_end(); 121 }; 122 123 124 class VM_GC_HeapInspection: public VM_GC_Operation { 125 private: 126 outputStream* _out; 127 bool _full_gc; 128 bool _csv_format; // "comma separated values" format for spreadsheet. 129 bool _print_help; 130 bool _print_class_stats; 131 const char* _columns; 132 public: VM_GC_HeapInspection(outputStream * out,bool request_full_gc)133 VM_GC_HeapInspection(outputStream* out, bool request_full_gc) : 134 VM_GC_Operation(0 /* total collections, dummy, ignored */, 135 GCCause::_heap_inspection /* GC Cause */, 136 0 /* total full collections, dummy, ignored */, 137 request_full_gc) { 138 _out = out; 139 _full_gc = request_full_gc; 140 _csv_format = false; 141 _print_help = false; 142 _print_class_stats = false; 143 _columns = NULL; 144 } 145 ~VM_GC_HeapInspection()146 ~VM_GC_HeapInspection() {} type() const147 virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; } 148 virtual bool skip_operation() const; 149 virtual void doit(); set_csv_format(bool value)150 void set_csv_format(bool value) {_csv_format = value;} set_print_help(bool value)151 void set_print_help(bool value) {_print_help = value;} set_print_class_stats(bool value)152 void set_print_class_stats(bool value) {_print_class_stats = value;} set_columns(const char * value)153 void set_columns(const char* value) {_columns = value;} 154 protected: 155 bool collect(); 156 }; 157 158 class VM_CollectForAllocation : public VM_GC_Operation { 159 protected: 160 size_t _word_size; // Size of object to be allocated (in number of words) 161 HeapWord* _result; // Allocation result (NULL if allocation failed) 162 163 public: 164 VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause); 165 result() const166 HeapWord* result() const { 167 return _result; 168 } 169 }; 170 171 class VM_GenCollectForAllocation : public VM_CollectForAllocation { 172 private: 173 bool _tlab; // alloc is of a tlab. 174 public: VM_GenCollectForAllocation(size_t word_size,bool tlab,uint gc_count_before)175 VM_GenCollectForAllocation(size_t word_size, 176 bool tlab, 177 uint gc_count_before) 178 : VM_CollectForAllocation(word_size, gc_count_before, GCCause::_allocation_failure), 179 _tlab(tlab) { 180 assert(word_size != 0, "An allocation should always be requested with this operation."); 181 } ~VM_GenCollectForAllocation()182 ~VM_GenCollectForAllocation() {} type() const183 virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; } 184 virtual void doit(); 185 }; 186 187 // VM operation to invoke a collection of the heap as a 188 // GenCollectedHeap heap. 189 class VM_GenCollectFull: public VM_GC_Operation { 190 private: 191 GenCollectedHeap::GenerationType _max_generation; 192 public: VM_GenCollectFull(uint gc_count_before,uint full_gc_count_before,GCCause::Cause gc_cause,GenCollectedHeap::GenerationType max_generation)193 VM_GenCollectFull(uint gc_count_before, 194 uint full_gc_count_before, 195 GCCause::Cause gc_cause, 196 GenCollectedHeap::GenerationType max_generation) 197 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, 198 max_generation != GenCollectedHeap::YoungGen /* full */), 199 _max_generation(max_generation) { } ~VM_GenCollectFull()200 ~VM_GenCollectFull() {} type() const201 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 type() const220 virtual VMOp_Type type() const { return VMOp_CollectForMetadataAllocation; } 221 virtual void doit(); result() const222 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 SvcGCMarker(reason_type reason)233 SvcGCMarker(reason_type reason ) { 234 VM_GC_Operation::notify_gc_begin(reason == FULL); 235 } 236 ~SvcGCMarker()237 ~SvcGCMarker() { 238 VM_GC_Operation::notify_gc_end(); 239 } 240 }; 241 242 #endif // SHARE_GC_SHARED_GCVMOPERATIONS_HPP 243