1 /* 2 * Copyright (c) 2000, 2012, 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 #include "precompiled.hpp" 26 #include "classfile/symbolTable.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "code/codeCache.hpp" 29 #include "gc_interface/collectedHeap.inline.hpp" 30 #include "memory/sharedHeap.hpp" 31 #include "oops/oop.inline.hpp" 32 #include "runtime/fprofiler.hpp" 33 #include "runtime/java.hpp" 34 #include "services/management.hpp" 35 #include "utilities/copy.hpp" 36 #include "utilities/workgroup.hpp" 37 38 SharedHeap* SharedHeap::_sh; 39 40 // The set of potentially parallel tasks in strong root scanning. 41 enum SH_process_strong_roots_tasks { 42 SH_PS_Universe_oops_do, 43 SH_PS_JNIHandles_oops_do, 44 SH_PS_ObjectSynchronizer_oops_do, 45 SH_PS_FlatProfiler_oops_do, 46 SH_PS_Management_oops_do, 47 SH_PS_SystemDictionary_oops_do, 48 SH_PS_jvmti_oops_do, 49 SH_PS_StringTable_oops_do, 50 SH_PS_CodeCache_oops_do, 51 // Leave this one last. 52 SH_PS_NumElements 53 }; 54 55 SharedHeap::SharedHeap(CollectorPolicy* policy_) : 56 CollectedHeap(), 57 _collector_policy(policy_), 58 _rem_set(NULL), 59 _strong_roots_parity(0), 60 _process_strong_tasks(new SubTasksDone(SH_PS_NumElements)), 61 _workers(NULL) 62 { 63 if (_process_strong_tasks == NULL || !_process_strong_tasks->valid()) { 64 vm_exit_during_initialization("Failed necessary allocation."); 65 } 66 _sh = this; // ch is static, should be set only once. 67 if ((UseParNewGC || 68 (UseConcMarkSweepGC && CMSParallelRemarkEnabled) || 69 UseG1GC) && 70 ParallelGCThreads > 0) { 71 _workers = new FlexibleWorkGang("Parallel GC Threads", ParallelGCThreads, 72 /* are_GC_task_threads */true, 73 /* are_ConcurrentGC_threads */false); 74 if (_workers == NULL) { 75 vm_exit_during_initialization("Failed necessary allocation."); 76 } else { 77 _workers->initialize_workers(); 78 } 79 } 80 } 81 82 int SharedHeap::n_termination() { 83 return _process_strong_tasks->n_threads(); 84 } 85 86 void SharedHeap::set_n_termination(int t) { 87 _process_strong_tasks->set_n_threads(t); 88 } 89 90 bool SharedHeap::heap_lock_held_for_gc() { 91 Thread* t = Thread::current(); 92 return Heap_lock->owned_by_self() 93 || ( (t->is_GC_task_thread() || t->is_VM_thread()) 94 && _thread_holds_heap_lock_for_gc); 95 } 96 97 void SharedHeap::set_par_threads(uint t) { 98 assert(t == 0 || !UseSerialGC, "Cannot have parallel threads"); 99 _n_par_threads = t; 100 _process_strong_tasks->set_n_threads(t); 101 } 102 103 #ifdef ASSERT 104 class AssertNonScavengableClosure: public OopClosure { 105 public: 106 virtual void do_oop(oop* p) { 107 assert(!Universe::heap()->is_in_partial_collection(*p), 108 "Referent should not be scavengable."); } 109 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); } 110 }; 111 static AssertNonScavengableClosure assert_is_non_scavengable_closure; 112 #endif 113 114 void SharedHeap::change_strong_roots_parity() { 115 // Also set the new collection parity. 116 assert(_strong_roots_parity >= 0 && _strong_roots_parity <= 2, 117 "Not in range."); 118 _strong_roots_parity++; 119 if (_strong_roots_parity == 3) _strong_roots_parity = 1; 120 assert(_strong_roots_parity >= 1 && _strong_roots_parity <= 2, 121 "Not in range."); 122 } 123 124 SharedHeap::StrongRootsScope::StrongRootsScope(SharedHeap* outer, bool activate) 125 : MarkScope(activate) 126 { 127 if (_active) { 128 outer->change_strong_roots_parity(); 129 } 130 } 131 132 SharedHeap::StrongRootsScope::~StrongRootsScope() { 133 // nothing particular 134 } 135 136 void SharedHeap::process_strong_roots(bool activate_scope, 137 bool is_scavenging, 138 ScanningOption so, 139 OopClosure* roots, 140 CodeBlobClosure* code_roots, 141 KlassClosure* klass_closure) { 142 StrongRootsScope srs(this, activate_scope); 143 144 // General strong roots. 145 assert(_strong_roots_parity != 0, "must have called prologue code"); 146 // _n_termination for _process_strong_tasks should be set up stream 147 // in a method not running in a GC worker. Otherwise the GC worker 148 // could be trying to change the termination condition while the task 149 // is executing in another GC worker. 150 if (!_process_strong_tasks->is_task_claimed(SH_PS_Universe_oops_do)) { 151 Universe::oops_do(roots); 152 } 153 // Global (strong) JNI handles 154 if (!_process_strong_tasks->is_task_claimed(SH_PS_JNIHandles_oops_do)) 155 JNIHandles::oops_do(roots); 156 // All threads execute this; the individual threads are task groups. 157 CLDToOopClosure roots_from_clds(roots); 158 CLDToOopClosure* roots_from_clds_p = (is_scavenging ? NULL : &roots_from_clds); 159 if (ParallelGCThreads > 0) { 160 Threads::possibly_parallel_oops_do(roots, roots_from_clds_p ,code_roots); 161 } else { 162 Threads::oops_do(roots, roots_from_clds_p, code_roots); 163 } 164 if (!_process_strong_tasks-> is_task_claimed(SH_PS_ObjectSynchronizer_oops_do)) 165 ObjectSynchronizer::oops_do(roots); 166 if (!_process_strong_tasks->is_task_claimed(SH_PS_FlatProfiler_oops_do)) 167 FlatProfiler::oops_do(roots); 168 if (!_process_strong_tasks->is_task_claimed(SH_PS_Management_oops_do)) 169 Management::oops_do(roots); 170 if (!_process_strong_tasks->is_task_claimed(SH_PS_jvmti_oops_do)) 171 JvmtiExport::oops_do(roots); 172 173 if (!_process_strong_tasks->is_task_claimed(SH_PS_SystemDictionary_oops_do)) { 174 if (so & SO_AllClasses) { 175 SystemDictionary::oops_do(roots); 176 ClassLoaderDataGraph::oops_do(roots, klass_closure, !is_scavenging); 177 } else if (so & SO_SystemClasses) { 178 SystemDictionary::always_strong_oops_do(roots); 179 ClassLoaderDataGraph::always_strong_oops_do(roots, klass_closure, !is_scavenging); 180 } else { 181 fatal("We should always have selected either SO_AllClasses or SO_SystemClasses"); 182 } 183 } 184 185 if (!_process_strong_tasks->is_task_claimed(SH_PS_StringTable_oops_do)) { 186 if (so & SO_Strings) { 187 StringTable::oops_do(roots); 188 } 189 } 190 191 if (!_process_strong_tasks->is_task_claimed(SH_PS_CodeCache_oops_do)) { 192 if (so & SO_CodeCache) { 193 assert(code_roots != NULL, "must supply closure for code cache"); 194 195 if (is_scavenging) { 196 // We only visit parts of the CodeCache when scavenging. 197 CodeCache::scavenge_root_nmethods_do(code_roots); 198 } else { 199 // CMSCollector uses this to do intermediate-strength collections. 200 // We scan the entire code cache, since CodeCache::do_unloading is not called. 201 CodeCache::blobs_do(code_roots); 202 } 203 } 204 // Verify that the code cache contents are not subject to 205 // movement by a scavenging collection. 206 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, /*do_marking=*/ false)); 207 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable)); 208 } 209 210 _process_strong_tasks->all_tasks_completed(); 211 } 212 213 class AlwaysTrueClosure: public BoolObjectClosure { 214 public: 215 bool do_object_b(oop p) { return true; } 216 }; 217 static AlwaysTrueClosure always_true; 218 219 void SharedHeap::process_weak_roots(OopClosure* root_closure, 220 CodeBlobClosure* code_roots) { 221 // Global (weak) JNI handles 222 JNIHandles::weak_oops_do(&always_true, root_closure); 223 224 CodeCache::blobs_do(code_roots); 225 StringTable::oops_do(root_closure); 226 } 227 228 void SharedHeap::set_barrier_set(BarrierSet* bs) { 229 _barrier_set = bs; 230 // Cached barrier set for fast access in oops 231 oopDesc::set_bs(bs); 232 } 233 234 void SharedHeap::post_initialize() { 235 ref_processing_init(); 236 } 237 238 void SharedHeap::ref_processing_init() {} 239 240 // Some utilities. 241 void SharedHeap::print_size_transition(outputStream* out, 242 size_t bytes_before, 243 size_t bytes_after, 244 size_t capacity) { 245 out->print(" %d%s->%d%s(%d%s)", 246 byte_size_in_proper_unit(bytes_before), 247 proper_unit_for_byte_size(bytes_before), 248 byte_size_in_proper_unit(bytes_after), 249 proper_unit_for_byte_size(bytes_after), 250 byte_size_in_proper_unit(capacity), 251 proper_unit_for_byte_size(capacity)); 252 }