1 /* 2 * Copyright (c) 2000, 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 #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_ClassLoaderDataGraph_oops_do, 49 SH_PS_jvmti_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 && (CMSParallelInitialMarkEnabled || 69 CMSParallelRemarkEnabled)) || 70 UseG1GC) && 71 ParallelGCThreads > 0) { 72 _workers = new FlexibleWorkGang("Parallel GC Threads", ParallelGCThreads, 73 /* are_GC_task_threads */true, 74 /* are_ConcurrentGC_threads */false); 75 if (_workers == NULL) { 76 vm_exit_during_initialization("Failed necessary allocation."); 77 } else { 78 _workers->initialize_workers(); 79 } 80 } 81 } 82 83 int SharedHeap::n_termination() { 84 return _process_strong_tasks->n_threads(); 85 } 86 87 void SharedHeap::set_n_termination(int t) { 88 _process_strong_tasks->set_n_threads(t); 89 } 90 91 bool SharedHeap::heap_lock_held_for_gc() { 92 Thread* t = Thread::current(); 93 return Heap_lock->owned_by_self() 94 || ( (t->is_GC_task_thread() || t->is_VM_thread()) 95 && _thread_holds_heap_lock_for_gc); 96 } 97 98 void SharedHeap::set_par_threads(uint t) { 99 assert(t == 0 || !UseSerialGC, "Cannot have parallel threads"); 100 _n_par_threads = t; 101 _process_strong_tasks->set_n_threads(t); 102 } 103 104 #ifdef ASSERT 105 class AssertNonScavengableClosure: public OopClosure { 106 public: 107 virtual void do_oop(oop* p) { 108 assert(!Universe::heap()->is_in_partial_collection(*p), 109 "Referent should not be scavengable."); } 110 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); } 111 }; 112 static AssertNonScavengableClosure assert_is_non_scavengable_closure; 113 #endif 114 115 void SharedHeap::change_strong_roots_parity() { 116 // Also set the new collection parity. 117 assert(_strong_roots_parity >= 0 && _strong_roots_parity <= 2, 118 "Not in range."); 119 _strong_roots_parity++; 120 if (_strong_roots_parity == 3) _strong_roots_parity = 1; 121 assert(_strong_roots_parity >= 1 && _strong_roots_parity <= 2, 122 "Not in range."); 123 } 124 125 SharedHeap::StrongRootsScope::StrongRootsScope(SharedHeap* outer, bool activate) 126 : MarkScope(activate) 127 { 128 if (_active) { 129 outer->change_strong_roots_parity(); 130 // Zero the claimed high water mark in the StringTable 131 StringTable::clear_parallel_claimed_index(); 132 } 133 } 134 135 SharedHeap::StrongRootsScope::~StrongRootsScope() { 136 // nothing particular 137 } 138 139 void SharedHeap::process_strong_roots(bool activate_scope, 140 bool is_scavenging, 141 ScanningOption so, 142 OopClosure* roots, 143 CodeBlobClosure* code_roots, 144 KlassClosure* klass_closure) { 145 StrongRootsScope srs(this, activate_scope); 146 147 // General strong roots. 148 assert(_strong_roots_parity != 0, "must have called prologue code"); 149 // _n_termination for _process_strong_tasks should be set up stream 150 // in a method not running in a GC worker. Otherwise the GC worker 151 // could be trying to change the termination condition while the task 152 // is executing in another GC worker. 153 if (!_process_strong_tasks->is_task_claimed(SH_PS_Universe_oops_do)) { 154 Universe::oops_do(roots); 155 } 156 // Global (strong) JNI handles 157 if (!_process_strong_tasks->is_task_claimed(SH_PS_JNIHandles_oops_do)) 158 JNIHandles::oops_do(roots); 159 160 // All threads execute this; the individual threads are task groups. 161 CLDToOopClosure roots_from_clds(roots); 162 CLDToOopClosure* roots_from_clds_p = (is_scavenging ? NULL : &roots_from_clds); 163 if (CollectedHeap::use_parallel_gc_threads()) { 164 Threads::possibly_parallel_oops_do(roots, roots_from_clds_p, code_roots); 165 } else { 166 Threads::oops_do(roots, roots_from_clds_p, code_roots); 167 } 168 169 if (!_process_strong_tasks-> is_task_claimed(SH_PS_ObjectSynchronizer_oops_do)) 170 ObjectSynchronizer::oops_do(roots); 171 if (!_process_strong_tasks->is_task_claimed(SH_PS_FlatProfiler_oops_do)) 172 FlatProfiler::oops_do(roots); 173 if (!_process_strong_tasks->is_task_claimed(SH_PS_Management_oops_do)) 174 Management::oops_do(roots); 175 if (!_process_strong_tasks->is_task_claimed(SH_PS_jvmti_oops_do)) 176 JvmtiExport::oops_do(roots); 177 178 if (!_process_strong_tasks->is_task_claimed(SH_PS_SystemDictionary_oops_do)) { 179 if (so & SO_AllClasses) { 180 SystemDictionary::oops_do(roots); 181 } else if (so & SO_SystemClasses) { 182 SystemDictionary::always_strong_oops_do(roots); 183 } else { 184 fatal("We should always have selected either SO_AllClasses or SO_SystemClasses"); 185 } 186 } 187 188 if (!_process_strong_tasks->is_task_claimed(SH_PS_ClassLoaderDataGraph_oops_do)) { 189 if (so & SO_AllClasses) { 190 ClassLoaderDataGraph::oops_do(roots, klass_closure, !is_scavenging); 191 } else if (so & SO_SystemClasses) { 192 ClassLoaderDataGraph::always_strong_oops_do(roots, klass_closure, !is_scavenging); 193 } 194 } 195 196 // All threads execute the following. A specific chunk of buckets 197 // from the StringTable are the individual tasks. 198 if (so & SO_Strings) { 199 if (CollectedHeap::use_parallel_gc_threads()) { 200 StringTable::possibly_parallel_oops_do(roots); 201 } else { 202 StringTable::oops_do(roots); 203 } 204 } 205 206 if (!_process_strong_tasks->is_task_claimed(SH_PS_CodeCache_oops_do)) { 207 if (so & SO_CodeCache) { 208 assert(code_roots != NULL, "must supply closure for code cache"); 209 210 if (is_scavenging) { 211 // We only visit parts of the CodeCache when scavenging. 212 CodeCache::scavenge_root_nmethods_do(code_roots); 213 } else { 214 // CMSCollector uses this to do intermediate-strength collections. 215 // We scan the entire code cache, since CodeCache::do_unloading is not called. 216 CodeCache::blobs_do(code_roots); 217 } 218 } 219 // Verify that the code cache contents are not subject to 220 // movement by a scavenging collection. 221 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, /*do_marking=*/ false)); 222 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable)); 223 } 224 225 _process_strong_tasks->all_tasks_completed(); 226 } 227 228 class AlwaysTrueClosure: public BoolObjectClosure { 229 public: 230 bool do_object_b(oop p) { return true; } 231 }; 232 static AlwaysTrueClosure always_true; 233 234 void SharedHeap::process_weak_roots(OopClosure* root_closure, 235 CodeBlobClosure* code_roots) { 236 // Global (weak) JNI handles 237 JNIHandles::weak_oops_do(&always_true, root_closure); 238 239 CodeCache::blobs_do(code_roots); 240 StringTable::oops_do(root_closure); 241 } 242 243 void SharedHeap::set_barrier_set(BarrierSet* bs) { 244 _barrier_set = bs; 245 // Cached barrier set for fast access in oops 246 oopDesc::set_bs(bs); 247 } 248 249 void SharedHeap::post_initialize() { 250 CollectedHeap::post_initialize(); 251 ref_processing_init(); 252 } 253 254 void SharedHeap::ref_processing_init() {} 255 256 // Some utilities. 257 void SharedHeap::print_size_transition(outputStream* out, 258 size_t bytes_before, 259 size_t bytes_after, 260 size_t capacity) { 261 out->print(" %d%s->%d%s(%d%s)", 262 byte_size_in_proper_unit(bytes_before), 263 proper_unit_for_byte_size(bytes_before), 264 byte_size_in_proper_unit(bytes_after), 265 proper_unit_for_byte_size(bytes_after), 266 byte_size_in_proper_unit(capacity), 267 proper_unit_for_byte_size(capacity)); 268 }