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--- old/src/share/vm/memory/sharedHeap.cpp
+++ new/src/share/vm/memory/sharedHeap.cpp
1 1 /*
2 2 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
3 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 4 *
5 5 * This code is free software; you can redistribute it and/or modify it
6 6 * under the terms of the GNU General Public License version 2 only, as
7 7 * published by the Free Software Foundation.
8 8 *
9 9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 12 * version 2 for more details (a copy is included in the LICENSE file that
13 13 * accompanied this code).
14 14 *
15 15 * You should have received a copy of the GNU General Public License version
16 16 * 2 along with this work; if not, write to the Free Software Foundation,
17 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 18 *
19 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 20 * or visit www.oracle.com if you need additional information or have any
21 21 * questions.
22 22 *
23 23 */
24 24
25 25 #include "precompiled.hpp"
26 26 #include "classfile/symbolTable.hpp"
27 27 #include "classfile/systemDictionary.hpp"
28 28 #include "code/codeCache.hpp"
29 29 #include "gc_interface/collectedHeap.inline.hpp"
30 30 #include "memory/sharedHeap.hpp"
31 31 #include "oops/oop.inline.hpp"
32 32 #include "runtime/fprofiler.hpp"
33 33 #include "runtime/java.hpp"
34 34 #include "services/management.hpp"
35 35 #include "utilities/copy.hpp"
36 36 #include "utilities/workgroup.hpp"
37 37
38 38 SharedHeap* SharedHeap::_sh;
39 39
40 40 // The set of potentially parallel tasks in strong root scanning.
41 41 enum SH_process_strong_roots_tasks {
42 42 SH_PS_Universe_oops_do,
43 43 SH_PS_JNIHandles_oops_do,
44 44 SH_PS_ObjectSynchronizer_oops_do,
45 45 SH_PS_FlatProfiler_oops_do,
46 46 SH_PS_Management_oops_do,
47 47 SH_PS_SystemDictionary_oops_do,
48 48 SH_PS_jvmti_oops_do,
49 49 SH_PS_CodeCache_oops_do,
50 50 // Leave this one last.
51 51 SH_PS_NumElements
52 52 };
53 53
54 54 SharedHeap::SharedHeap(CollectorPolicy* policy_) :
55 55 CollectedHeap(),
56 56 _collector_policy(policy_),
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57 57 _perm_gen(NULL), _rem_set(NULL),
58 58 _strong_roots_parity(0),
59 59 _process_strong_tasks(new SubTasksDone(SH_PS_NumElements)),
60 60 _workers(NULL)
61 61 {
62 62 if (_process_strong_tasks == NULL || !_process_strong_tasks->valid()) {
63 63 vm_exit_during_initialization("Failed necessary allocation.");
64 64 }
65 65 _sh = this; // ch is static, should be set only once.
66 66 if ((UseParNewGC ||
67 - (UseConcMarkSweepGC && CMSParallelRemarkEnabled) ||
67 + (UseConcMarkSweepGC && (CMSParallelInitialMarkEnabled ||
68 + CMSParallelRemarkEnabled)) ||
68 69 UseG1GC) &&
69 70 ParallelGCThreads > 0) {
70 71 _workers = new FlexibleWorkGang("Parallel GC Threads", ParallelGCThreads,
71 72 /* are_GC_task_threads */true,
72 73 /* are_ConcurrentGC_threads */false);
73 74 if (_workers == NULL) {
74 75 vm_exit_during_initialization("Failed necessary allocation.");
75 76 } else {
76 77 _workers->initialize_workers();
77 78 }
78 79 }
79 80 }
80 81
81 82 int SharedHeap::n_termination() {
82 83 return _process_strong_tasks->n_threads();
83 84 }
84 85
85 86 void SharedHeap::set_n_termination(int t) {
86 87 _process_strong_tasks->set_n_threads(t);
87 88 }
88 89
89 90 bool SharedHeap::heap_lock_held_for_gc() {
90 91 Thread* t = Thread::current();
91 92 return Heap_lock->owned_by_self()
92 93 || ( (t->is_GC_task_thread() || t->is_VM_thread())
93 94 && _thread_holds_heap_lock_for_gc);
94 95 }
95 96
96 97 void SharedHeap::set_par_threads(uint t) {
97 98 assert(t == 0 || !UseSerialGC, "Cannot have parallel threads");
98 99 _n_par_threads = t;
99 100 _process_strong_tasks->set_n_threads(t);
100 101 }
101 102
102 103 class AssertIsPermClosure: public OopClosure {
103 104 public:
104 105 virtual void do_oop(oop* p) {
105 106 assert((*p) == NULL || (*p)->is_perm(), "Referent should be perm.");
106 107 }
107 108 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
108 109 };
109 110 static AssertIsPermClosure assert_is_perm_closure;
110 111
111 112 #ifdef ASSERT
112 113 class AssertNonScavengableClosure: public OopClosure {
113 114 public:
114 115 virtual void do_oop(oop* p) {
115 116 assert(!Universe::heap()->is_in_partial_collection(*p),
116 117 "Referent should not be scavengable."); }
117 118 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
118 119 };
119 120 static AssertNonScavengableClosure assert_is_non_scavengable_closure;
120 121 #endif
121 122
122 123 void SharedHeap::change_strong_roots_parity() {
123 124 // Also set the new collection parity.
124 125 assert(_strong_roots_parity >= 0 && _strong_roots_parity <= 2,
125 126 "Not in range.");
126 127 _strong_roots_parity++;
127 128 if (_strong_roots_parity == 3) _strong_roots_parity = 1;
128 129 assert(_strong_roots_parity >= 1 && _strong_roots_parity <= 2,
129 130 "Not in range.");
130 131 }
131 132
132 133 SharedHeap::StrongRootsScope::StrongRootsScope(SharedHeap* outer, bool activate)
133 134 : MarkScope(activate)
134 135 {
135 136 if (_active) {
136 137 outer->change_strong_roots_parity();
137 138 // Zero the claimed high water mark in the StringTable
138 139 StringTable::clear_parallel_claimed_index();
139 140 }
140 141 }
141 142
142 143 SharedHeap::StrongRootsScope::~StrongRootsScope() {
143 144 // nothing particular
144 145 }
145 146
146 147 void SharedHeap::process_strong_roots(bool activate_scope,
147 148 bool collecting_perm_gen,
148 149 ScanningOption so,
149 150 OopClosure* roots,
150 151 CodeBlobClosure* code_roots,
151 152 OopsInGenClosure* perm_blk,
152 153 bool manages_code_roots) {
153 154 StrongRootsScope srs(this, activate_scope);
154 155 // General strong roots.
155 156 assert(_strong_roots_parity != 0, "must have called prologue code");
156 157 // _n_termination for _process_strong_tasks should be set up stream
157 158 // in a method not running in a GC worker. Otherwise the GC worker
158 159 // could be trying to change the termination condition while the task
159 160 // is executing in another GC worker.
160 161 if (!_process_strong_tasks->is_task_claimed(SH_PS_Universe_oops_do)) {
161 162 Universe::oops_do(roots);
162 163 // Consider perm-gen discovered lists to be strong.
163 164 perm_gen()->ref_processor()->weak_oops_do(roots);
164 165 }
165 166 // Global (strong) JNI handles
166 167 if (!_process_strong_tasks->is_task_claimed(SH_PS_JNIHandles_oops_do))
167 168 JNIHandles::oops_do(roots);
168 169
169 170 // All threads execute this; the individual threads are task groups.
170 171 if (CollectedHeap::use_parallel_gc_threads()) {
171 172 Threads::possibly_parallel_oops_do(roots, code_roots);
172 173 } else {
173 174 Threads::oops_do(roots, code_roots);
174 175 }
175 176
176 177 if (!_process_strong_tasks-> is_task_claimed(SH_PS_ObjectSynchronizer_oops_do))
177 178 ObjectSynchronizer::oops_do(roots);
178 179 if (!_process_strong_tasks->is_task_claimed(SH_PS_FlatProfiler_oops_do))
179 180 FlatProfiler::oops_do(roots);
180 181 if (!_process_strong_tasks->is_task_claimed(SH_PS_Management_oops_do))
181 182 Management::oops_do(roots);
182 183 if (!_process_strong_tasks->is_task_claimed(SH_PS_jvmti_oops_do))
183 184 JvmtiExport::oops_do(roots);
184 185
185 186 if (!_process_strong_tasks->is_task_claimed(SH_PS_SystemDictionary_oops_do)) {
186 187 if (so & SO_AllClasses) {
187 188 SystemDictionary::oops_do(roots);
188 189 } else if (so & SO_SystemClasses) {
189 190 SystemDictionary::always_strong_oops_do(roots);
190 191 }
191 192 }
192 193
193 194 // All threads execute the following. A specific chunk of buckets
194 195 // from the StringTable are the individual tasks.
195 196 if (so & SO_Strings || (!collecting_perm_gen && !JavaObjectsInPerm)) {
196 197 if (CollectedHeap::use_parallel_gc_threads()) {
197 198 StringTable::possibly_parallel_oops_do(roots);
198 199 } else {
199 200 StringTable::oops_do(roots);
200 201 }
201 202 }
202 203 if (JavaObjectsInPerm) {
203 204 // Verify the string table contents are in the perm gen
204 205 if (CollectedHeap::use_parallel_gc_threads()) {
205 206 NOT_PRODUCT(StringTable::possibly_parallel_oops_do(&assert_is_perm_closure));
206 207 } else {
207 208 NOT_PRODUCT(StringTable::oops_do(&assert_is_perm_closure));
208 209 }
209 210 }
210 211
211 212 if (!_process_strong_tasks->is_task_claimed(SH_PS_CodeCache_oops_do)) {
212 213 if (so & SO_CodeCache) {
213 214 // (Currently, CMSCollector uses this to do intermediate-strength collections.)
214 215 assert(collecting_perm_gen, "scanning all of code cache");
215 216 assert(code_roots != NULL, "must supply closure for code cache");
216 217 if (code_roots != NULL) {
217 218 CodeCache::blobs_do(code_roots);
218 219 }
219 220 } else if (so & (SO_SystemClasses|SO_AllClasses)) {
220 221 if (!manages_code_roots && !collecting_perm_gen) {
221 222 // If we are collecting from class statics, but we are not going to
222 223 // visit all of the CodeCache, collect from the non-perm roots if any.
223 224 // This makes the code cache function temporarily as a source of strong
224 225 // roots for oops, until the next major collection.
225 226 //
226 227 // If collecting_perm_gen is true, we require that this phase will call
227 228 // CodeCache::do_unloading. This will kill off nmethods with expired
228 229 // weak references, such as stale invokedynamic targets.
229 230 CodeCache::scavenge_root_nmethods_do(code_roots);
230 231 }
231 232 }
232 233 // Verify that the code cache contents are not subject to
233 234 // movement by a scavenging collection.
234 235 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, /*do_marking=*/ false));
235 236 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
236 237 }
237 238
238 239 if (!collecting_perm_gen) {
239 240 // All threads perform this; coordination is handled internally.
240 241
241 242 rem_set()->younger_refs_iterate(perm_gen(), perm_blk);
242 243 }
243 244 _process_strong_tasks->all_tasks_completed();
244 245 }
245 246
246 247 class AlwaysTrueClosure: public BoolObjectClosure {
247 248 public:
248 249 void do_object(oop p) { ShouldNotReachHere(); }
249 250 bool do_object_b(oop p) { return true; }
250 251 };
251 252 static AlwaysTrueClosure always_true;
252 253
253 254 class SkipAdjustingSharedStrings: public OopClosure {
254 255 OopClosure* _clo;
255 256 public:
256 257 SkipAdjustingSharedStrings(OopClosure* clo) : _clo(clo) {}
257 258
258 259 virtual void do_oop(oop* p) {
259 260 oop o = (*p);
260 261 if (!o->is_shared_readwrite()) {
261 262 _clo->do_oop(p);
262 263 }
263 264 }
264 265 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
265 266 };
266 267
267 268 // Unmarked shared Strings in the StringTable (which got there due to
268 269 // being in the constant pools of as-yet unloaded shared classes) were
269 270 // not marked and therefore did not have their mark words preserved.
270 271 // These entries are also deliberately not purged from the string
271 272 // table during unloading of unmarked strings. If an identity hash
272 273 // code was computed for any of these objects, it will not have been
273 274 // cleared to zero during the forwarding process or by the
274 275 // RecursiveAdjustSharedObjectClosure, and will be confused by the
275 276 // adjusting process as a forwarding pointer. We need to skip
276 277 // forwarding StringTable entries which contain unmarked shared
277 278 // Strings. Actually, since shared strings won't be moving, we can
278 279 // just skip adjusting any shared entries in the string table.
279 280
280 281 void SharedHeap::process_weak_roots(OopClosure* root_closure,
281 282 CodeBlobClosure* code_roots,
282 283 OopClosure* non_root_closure) {
283 284 // Global (weak) JNI handles
284 285 JNIHandles::weak_oops_do(&always_true, root_closure);
285 286
286 287 CodeCache::blobs_do(code_roots);
287 288 if (UseSharedSpaces && !DumpSharedSpaces) {
288 289 SkipAdjustingSharedStrings skip_closure(root_closure);
289 290 StringTable::oops_do(&skip_closure);
290 291 } else {
291 292 StringTable::oops_do(root_closure);
292 293 }
293 294 }
294 295
295 296 void SharedHeap::set_barrier_set(BarrierSet* bs) {
296 297 _barrier_set = bs;
297 298 // Cached barrier set for fast access in oops
298 299 oopDesc::set_bs(bs);
299 300 }
300 301
301 302 void SharedHeap::post_initialize() {
302 303 ref_processing_init();
303 304 }
304 305
305 306 void SharedHeap::ref_processing_init() {
306 307 perm_gen()->ref_processor_init();
307 308 }
308 309
309 310 // Some utilities.
310 311 void SharedHeap::print_size_transition(outputStream* out,
311 312 size_t bytes_before,
312 313 size_t bytes_after,
313 314 size_t capacity) {
314 315 out->print(" %d%s->%d%s(%d%s)",
315 316 byte_size_in_proper_unit(bytes_before),
316 317 proper_unit_for_byte_size(bytes_before),
317 318 byte_size_in_proper_unit(bytes_after),
318 319 proper_unit_for_byte_size(bytes_after),
319 320 byte_size_in_proper_unit(capacity),
320 321 proper_unit_for_byte_size(capacity));
321 322 }
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