1 /* 2 * Copyright (c) 2005, 2013, 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_ParallelGCSystemGC 46 // VM_GC_Operation 47 // - implements methods common to all classes in the hierarchy: 48 // prevents multiple gc requests and manages lock on heap; 49 // 50 // VM_GC_HeapInspection 51 // - prints class histogram on SIGBREAK if PrintClassHistogram 52 // is specified; and also the attach "inspectheap" operation 53 // 54 // VM_GenCollectForAllocation 55 // VM_ParallelGCFailedAllocation 56 // - this operation is invoked when allocation is failed; 57 // operation performs garbage collection and tries to 58 // allocate afterwards; 59 // 60 // VM_GenCollectFull 61 // VM_GenCollectFullConcurrent 62 // VM_ParallelGCSystemGC 63 // - these operations preform full collection of heaps of 64 // different kind 65 // 66 67 class VM_GC_Operation: public VM_Operation { 68 protected: 69 BasicLock _pending_list_basic_lock; // for refs pending list notification (PLL) 70 unsigned int _gc_count_before; // gc count before acquiring PLL 71 unsigned int _full_gc_count_before; // full gc count before acquiring PLL 72 bool _full; // whether a "full" collection 73 bool _prologue_succeeded; // whether doit_prologue succeeded 74 GCCause::Cause _gc_cause; // the putative cause for this gc op 75 bool _gc_locked; // will be set if gc was locked 76 77 virtual bool skip_operation() const; 78 79 // java.lang.ref.Reference support 80 void acquire_pending_list_lock(); 81 void release_and_notify_pending_list_lock(); 82 83 public: 84 VM_GC_Operation(unsigned int gc_count_before, 85 GCCause::Cause _cause, 86 unsigned int 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 CollectedHeap* ch = Universe::heap(); 109 ch->collector_policy()->set_all_soft_refs_clear(false); 110 } 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 }; 162 163 164 class VM_GenCollectForAllocation: public VM_GC_Operation { 165 private: 166 HeapWord* _res; 167 size_t _size; // size of object to be allocated. 168 bool _tlab; // alloc is of a tlab. 169 public: 170 VM_GenCollectForAllocation(size_t size, 171 bool tlab, 172 unsigned int gc_count_before) 173 : VM_GC_Operation(gc_count_before, GCCause::_allocation_failure), 174 _size(size), 175 _tlab(tlab) { 176 _res = NULL; 177 } 178 ~VM_GenCollectForAllocation() {} 179 virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; } 180 virtual void doit(); 181 HeapWord* result() const { return _res; } 182 }; 183 184 185 // VM operation to invoke a collection of the heap as a 186 // GenCollectedHeap heap. 187 class VM_GenCollectFull: public VM_GC_Operation { 188 private: 189 int _max_level; 190 public: 191 VM_GenCollectFull(unsigned int gc_count_before, 192 unsigned int full_gc_count_before, 193 GCCause::Cause gc_cause, 194 int max_level) 195 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true /* full */), 196 _max_level(max_level) { } 197 ~VM_GenCollectFull() {} 198 virtual VMOp_Type type() const { return VMOp_GenCollectFull; } 199 virtual void doit(); 200 }; 201 202 class VM_CollectForMetadataAllocation: public VM_GC_Operation { 203 private: 204 MetaWord* _result; 205 size_t _size; // size of object to be allocated 206 Metaspace::MetadataType _mdtype; 207 ClassLoaderData* _loader_data; 208 public: 209 VM_CollectForMetadataAllocation(ClassLoaderData* loader_data, 210 size_t size, Metaspace::MetadataType mdtype, 211 unsigned int gc_count_before, 212 unsigned int full_gc_count_before, 213 GCCause::Cause gc_cause) 214 : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true), 215 _loader_data(loader_data), _size(size), _mdtype(mdtype), _result(NULL) { 216 } 217 virtual VMOp_Type type() const { return VMOp_CollectForMetadataAllocation; } 218 virtual void doit(); 219 MetaWord* result() const { return _result; } 220 221 bool initiate_concurrent_GC(); 222 }; 223 224 class SvcGCMarker : public StackObj { 225 private: 226 JvmtiGCMarker _jgcm; 227 public: 228 typedef enum { MINOR, FULL, OTHER } reason_type; 229 230 SvcGCMarker(reason_type reason ) { 231 VM_GC_Operation::notify_gc_begin(reason == FULL); 232 } 233 234 ~SvcGCMarker() { 235 VM_GC_Operation::notify_gc_end(); 236 } 237 }; 238 239 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP