1 /* 2 * Copyright (c) 2005, 2015, 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 "gc_interface/collectedHeap.hpp" 29 #include "memory/heapInspection.hpp" 30 #include "runtime/handles.hpp" 31 #include "runtime/jniHandles.hpp" 32 #include "runtime/synchronizer.hpp" 33 #include "runtime/vm_operations.hpp" 34 #include "prims/jvmtiExport.hpp" 35 36 // The following class hierarchy represents 37 // a set of operations (VM_Operation) related to GC. 38 // 39 // VM_Operation 40 // VM_GC_Operation 41 // VM_GC_HeapInspection 42 // VM_GenCollectFull 43 // VM_GenCollectFullConcurrent 44 // VM_ParallelGCSystemGC 45 // VM_CollectForAllocation 46 // VM_GenCollectForAllocation 47 // VM_ParallelGCFailedAllocation 48 // VM_GC_Operation 49 // - implements methods common to all classes in the hierarchy: 50 // prevents multiple gc requests and manages lock on heap; 51 // 52 // VM_GC_HeapInspection 53 // - prints class histogram on SIGBREAK if PrintClassHistogram 54 // is specified; and also the attach "inspectheap" operation 55 // 56 // VM_CollectForAllocation 57 // VM_GenCollectForAllocation 58 // VM_ParallelGCFailedAllocation 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 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 // 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(uint gc_count_before, 88 GCCause::Cause _cause, 89 uint full_gc_count_before = 0, 90 bool full = false) { 91 _full = full; 92 _prologue_succeeded = false; 93 _gc_count_before = gc_count_before; 94 95 // A subclass constructor will likely overwrite the following 96 _gc_cause = _cause; 97 98 _gc_locked = false; 99 100 _full_gc_count_before = full_gc_count_before; 101 // In ParallelScavengeHeap::mem_allocate() collections can be 102 // executed within a loop and _all_soft_refs_clear can be set 103 // true after they have been cleared by a collection and another 104 // collection started so that _all_soft_refs_clear can be true 105 // when this collection is started. Don't assert that 106 // _all_soft_refs_clear have to be false here even though 107 // mutators have run. Soft refs will be cleared again in this 108 // collection. 109 } 110 ~VM_GC_Operation(); 111 112 // Acquire the reference synchronization lock 113 virtual bool doit_prologue(); 114 // Do notifyAll (if needed) and release held lock 115 virtual void doit_epilogue(); 116 117 virtual bool allow_nested_vm_operations() const { return true; } 118 bool prologue_succeeded() const { return _prologue_succeeded; } 119 120 void set_gc_locked() { _gc_locked = true; } 121 bool gc_locked() const { return _gc_locked; } 122 123 static void notify_gc_begin(bool full = false); 124 static void notify_gc_end(); 125 }; 126 127 128 class VM_GC_HeapInspection: public VM_GC_Operation { 129 private: 130 outputStream* _out; 131 bool _full_gc; 132 bool _csv_format; // "comma separated values" format for spreadsheet. 133 bool _print_help; 134 bool _print_class_stats; 135 const char* _columns; 136 public: 137 VM_GC_HeapInspection(outputStream* out, bool request_full_gc) : 138 VM_GC_Operation(0 /* total collections, dummy, ignored */, 139 GCCause::_heap_inspection /* GC Cause */, 140 0 /* total full collections, dummy, ignored */, 141 request_full_gc) { 142 _out = out; 143 _full_gc = request_full_gc; 144 _csv_format = false; 145 _print_help = false; 146 _print_class_stats = false; 147 _columns = NULL; 148 } 149 150 ~VM_GC_HeapInspection() {} 151 virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; } 152 virtual bool skip_operation() const; 153 virtual bool doit_prologue(); 154 virtual void doit(); 155 void set_csv_format(bool value) {_csv_format = value;} 156 void set_print_help(bool value) {_print_help = value;} 157 void set_print_class_stats(bool value) {_print_class_stats = value;} 158 void set_columns(const char* value) {_columns = value;} 159 protected: 160 bool collect(); 161 }; 162 163 class VM_CollectForAllocation : public VM_GC_Operation { 164 protected: 165 size_t _word_size; // Size of object to be allocated (in number of words) 166 HeapWord* _result; // Allocation result (NULL if allocation failed) 167 168 public: 169 VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause) 170 : VM_GC_Operation(gc_count_before, cause), _result(NULL), _word_size(word_size) {} 171 172 HeapWord* result() const { 173 return _result; 174 } 175 }; 176 177 class VM_GenCollectForAllocation : public VM_CollectForAllocation { 178 private: 179 bool _tlab; // alloc is of a tlab. 180 public: 181 VM_GenCollectForAllocation(size_t word_size, 182 bool tlab, 183 uint gc_count_before) 184 : VM_CollectForAllocation(word_size, gc_count_before, GCCause::_allocation_failure), 185 _tlab(tlab) { 186 assert(word_size != 0, "An allocation should always be requested with this operation."); 187 } 188 ~VM_GenCollectForAllocation() {} 189 virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; } 190 virtual void doit(); 191 }; 192 193 // VM operation to invoke a collection of the heap as a 194 // GenCollectedHeap heap. 195 class VM_GenCollectFull: public VM_GC_Operation { 196 private: 197 int _max_level; 198 public: 199 VM_GenCollectFull(uint gc_count_before, 200 uint full_gc_count_before, 201 GCCause::Cause gc_cause, 202 int max_level) 203 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true /* full */), 204 _max_level(max_level) { } 205 ~VM_GenCollectFull() {} 206 virtual VMOp_Type type() const { return VMOp_GenCollectFull; } 207 virtual void doit(); 208 }; 209 210 class VM_CollectForMetadataAllocation: public VM_GC_Operation { 211 private: 212 MetaWord* _result; 213 size_t _size; // size of object to be allocated 214 Metaspace::MetadataType _mdtype; 215 ClassLoaderData* _loader_data; 216 public: 217 VM_CollectForMetadataAllocation(ClassLoaderData* loader_data, 218 size_t size, Metaspace::MetadataType mdtype, 219 uint gc_count_before, 220 uint full_gc_count_before, 221 GCCause::Cause gc_cause) 222 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true), 223 _loader_data(loader_data), _size(size), _mdtype(mdtype), _result(NULL) { 224 } 225 virtual VMOp_Type type() const { return VMOp_CollectForMetadataAllocation; } 226 virtual void doit(); 227 MetaWord* result() const { return _result; } 228 229 bool initiate_concurrent_GC(); 230 }; 231 232 class SvcGCMarker : public StackObj { 233 private: 234 JvmtiGCMarker _jgcm; 235 public: 236 typedef enum { MINOR, FULL, OTHER } reason_type; 237 238 SvcGCMarker(reason_type reason ) { 239 VM_GC_Operation::notify_gc_begin(reason == FULL); 240 } 241 242 ~SvcGCMarker() { 243 VM_GC_Operation::notify_gc_end(); 244 } 245 }; 246 247 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP