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 #include "precompiled.hpp"
26 #include "classfile/systemDictionary.hpp"
27 #include "gc_implementation/parallelScavenge/gcTaskManager.hpp"
28 #include "gc_implementation/parallelScavenge/objectStartArray.hpp"
29 #include "gc_implementation/parallelScavenge/parMarkBitMap.hpp"
30 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
31 #include "gc_implementation/parallelScavenge/psCompactionManager.inline.hpp"
32 #include "gc_implementation/parallelScavenge/psOldGen.hpp"
33 #include "gc_implementation/parallelScavenge/psParallelCompact.inline.hpp"
34 #include "memory/iterator.inline.hpp"
35 #include "oops/instanceKlass.inline.hpp"
36 #include "oops/instanceMirrorKlass.inline.hpp"
37 #include "oops/objArrayKlass.inline.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "runtime/atomic.inline.hpp"
40 #include "utilities/stack.inline.hpp"
41
42 PSOldGen* ParCompactionManager::_old_gen = NULL;
43 ParCompactionManager** ParCompactionManager::_manager_array = NULL;
44
45 RegionTaskQueue** ParCompactionManager::_region_list = NULL;
46
47 OopTaskQueueSet* ParCompactionManager::_stack_array = NULL;
48 ParCompactionManager::ObjArrayTaskQueueSet*
49 ParCompactionManager::_objarray_queues = NULL;
50 ObjectStartArray* ParCompactionManager::_start_array = NULL;
51 ParMarkBitMap* ParCompactionManager::_mark_bitmap = NULL;
52 RegionTaskQueueSet* ParCompactionManager::_region_array = NULL;
53
54 uint* ParCompactionManager::_recycled_stack_index = NULL;
55 int ParCompactionManager::_recycled_top = -1;
56 int ParCompactionManager::_recycled_bottom = -1;
57
58 ParCompactionManager::ParCompactionManager() :
59 _action(CopyAndUpdate),
60 _region_stack(NULL),
61 _region_stack_index((uint)max_uintx) {
62
63 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
64
65 _old_gen = heap->old_gen();
66 _start_array = old_gen()->start_array();
67
68 marking_stack()->initialize();
69 _objarray_stack.initialize();
70 }
71
72 ParCompactionManager::~ParCompactionManager() {
73 delete _recycled_stack_index;
74 }
75
76 void ParCompactionManager::initialize(ParMarkBitMap* mbm) {
77 assert(PSParallelCompact::gc_task_manager() != NULL,
78 "Needed for initialization");
79
80 _mark_bitmap = mbm;
81
82 uint parallel_gc_threads = PSParallelCompact::gc_task_manager()->workers();
83
84 assert(_manager_array == NULL, "Attempt to initialize twice");
85 _manager_array = NEW_C_HEAP_ARRAY(ParCompactionManager*, parallel_gc_threads+1, mtGC);
86 guarantee(_manager_array != NULL, "Could not allocate manager_array");
87
88 _region_list = NEW_C_HEAP_ARRAY(RegionTaskQueue*,
89 parallel_gc_threads+1, mtGC);
90 guarantee(_region_list != NULL, "Could not initialize promotion manager");
91
92 _recycled_stack_index = NEW_C_HEAP_ARRAY(uint, parallel_gc_threads, mtGC);
93
94 // parallel_gc-threads + 1 to be consistent with the number of
95 // compaction managers.
96 for(uint i=0; i<parallel_gc_threads + 1; i++) {
97 _region_list[i] = new RegionTaskQueue();
98 region_list(i)->initialize();
99 }
100
101 _stack_array = new OopTaskQueueSet(parallel_gc_threads);
102 guarantee(_stack_array != NULL, "Could not allocate stack_array");
103 _objarray_queues = new ObjArrayTaskQueueSet(parallel_gc_threads);
104 guarantee(_objarray_queues != NULL, "Could not allocate objarray_queues");
105 _region_array = new RegionTaskQueueSet(parallel_gc_threads);
106 guarantee(_region_array != NULL, "Could not allocate region_array");
107
108 // Create and register the ParCompactionManager(s) for the worker threads.
109 for(uint i=0; i<parallel_gc_threads; i++) {
110 _manager_array[i] = new ParCompactionManager();
111 guarantee(_manager_array[i] != NULL, "Could not create ParCompactionManager");
112 stack_array()->register_queue(i, _manager_array[i]->marking_stack());
113 _objarray_queues->register_queue(i, &_manager_array[i]->_objarray_stack);
114 region_array()->register_queue(i, region_list(i));
115 }
116
117 // The VMThread gets its own ParCompactionManager, which is not available
118 // for work stealing.
119 _manager_array[parallel_gc_threads] = new ParCompactionManager();
120 guarantee(_manager_array[parallel_gc_threads] != NULL,
121 "Could not create ParCompactionManager");
122 assert(PSParallelCompact::gc_task_manager()->workers() != 0,
123 "Not initialized?");
124 }
125
126 int ParCompactionManager::pop_recycled_stack_index() {
127 assert(_recycled_bottom <= _recycled_top, "list is empty");
128 // Get the next available index
129 if (_recycled_bottom < _recycled_top) {
130 uint cur, next, last;
131 do {
132 cur = _recycled_bottom;
133 next = cur + 1;
134 last = Atomic::cmpxchg(next, &_recycled_bottom, cur);
135 } while (cur != last);
136 return _recycled_stack_index[next];
137 } else {
138 return -1;
139 }
140 }
141
142 void ParCompactionManager::push_recycled_stack_index(uint v) {
143 // Get the next available index
144 int cur = Atomic::add(1, &_recycled_top);
145 _recycled_stack_index[cur] = v;
146 assert(_recycled_bottom <= _recycled_top, "list top and bottom are wrong");
147 }
148
149 bool ParCompactionManager::should_update() {
150 assert(action() != NotValid, "Action is not set");
151 return (action() == ParCompactionManager::Update) ||
152 (action() == ParCompactionManager::CopyAndUpdate) ||
153 (action() == ParCompactionManager::UpdateAndCopy);
154 }
155
156 bool ParCompactionManager::should_copy() {
157 assert(action() != NotValid, "Action is not set");
158 return (action() == ParCompactionManager::Copy) ||
159 (action() == ParCompactionManager::CopyAndUpdate) ||
160 (action() == ParCompactionManager::UpdateAndCopy);
161 }
162
163 void ParCompactionManager::region_list_push(uint list_index,
164 size_t region_index) {
165 region_list(list_index)->push(region_index);
166 }
167
168 void ParCompactionManager::verify_region_list_empty(uint list_index) {
169 assert(region_list(list_index)->is_empty(), "Not empty");
170 }
171
172 ParCompactionManager*
173 ParCompactionManager::gc_thread_compaction_manager(int index) {
174 assert(index >= 0 && index < (int)ParallelGCThreads, "index out of range");
175 assert(_manager_array != NULL, "Sanity");
176 return _manager_array[index];
177 }
178
179 void InstanceKlass::oop_pc_follow_contents(oop obj, ParCompactionManager* cm) {
180 assert(obj != NULL, "can't follow the content of NULL object");
181
182 cm->follow_klass(this);
183 // Only mark the header and let the scan of the meta-data mark
184 // everything else.
185
186 ParCompactionManager::MarkAndPushClosure cl(cm);
187 InstanceKlass::oop_oop_iterate_oop_maps<true>(obj, &cl);
188 }
189
190 void InstanceMirrorKlass::oop_pc_follow_contents(oop obj, ParCompactionManager* cm) {
191 InstanceKlass::oop_pc_follow_contents(obj, cm);
192
193 // Follow the klass field in the mirror.
194 Klass* klass = java_lang_Class::as_Klass(obj);
195 if (klass != NULL) {
196 // An anonymous class doesn't have its own class loader, so the call
197 // to follow_klass will mark and push its java mirror instead of the
198 // class loader. When handling the java mirror for an anonymous class
199 // we need to make sure its class loader data is claimed, this is done
200 // by calling follow_class_loader explicitly. For non-anonymous classes
201 // the call to follow_class_loader is made when the class loader itself
202 // is handled.
203 if (klass->oop_is_instance() && InstanceKlass::cast(klass)->is_anonymous()) {
204 PSParallelCompact::follow_class_loader(cm, klass->class_loader_data());
205 } else {
206 cm->follow_klass(klass);
207 }
208 } else {
209 // If klass is NULL then this a mirror for a primitive type.
210 // We don't have to follow them, since they are handled as strong
211 // roots in Universe::oops_do.
212 assert(java_lang_Class::is_primitive(obj), "Sanity check");
213 }
214
215 ParCompactionManager::MarkAndPushClosure cl(cm);
216 oop_oop_iterate_statics<true>(obj, &cl);
217 }
218
219 void InstanceClassLoaderKlass::oop_pc_follow_contents(oop obj, ParCompactionManager* cm) {
220 InstanceKlass::oop_pc_follow_contents(obj, cm);
221
222 ClassLoaderData * const loader_data = java_lang_ClassLoader::loader_data(obj);
223 if (loader_data != NULL) {
224 PSParallelCompact::follow_class_loader(cm, loader_data);
225 }
226 }
227
228 template <class T>
229 static void oop_pc_follow_contents_specialized(InstanceRefKlass* klass, oop obj, ParCompactionManager* cm) {
230 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
231 T heap_oop = oopDesc::load_heap_oop(referent_addr);
232 debug_only(
233 if(TraceReferenceGC && PrintGCDetails) {
234 gclog_or_tty->print_cr("InstanceRefKlass::oop_pc_follow_contents " PTR_FORMAT, p2i(obj));
235 }
236 )
237 if (!oopDesc::is_null(heap_oop)) {
238 oop referent = oopDesc::decode_heap_oop_not_null(heap_oop);
239 if (PSParallelCompact::mark_bitmap()->is_unmarked(referent) &&
240 PSParallelCompact::ref_processor()->discover_reference(obj, klass->reference_type())) {
241 // reference already enqueued, referent will be traversed later
242 klass->InstanceKlass::oop_pc_follow_contents(obj, cm);
243 debug_only(
244 if(TraceReferenceGC && PrintGCDetails) {
245 gclog_or_tty->print_cr(" Non NULL enqueued " PTR_FORMAT, p2i(obj));
246 }
247 )
248 return;
249 } else {
250 // treat referent as normal oop
251 debug_only(
252 if(TraceReferenceGC && PrintGCDetails) {
253 gclog_or_tty->print_cr(" Non NULL normal " PTR_FORMAT, p2i(obj));
254 }
255 )
256 cm->mark_and_push(referent_addr);
257 }
258 }
259 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
260 if (ReferenceProcessor::pending_list_uses_discovered_field()) {
261 // Treat discovered as normal oop, if ref is not "active",
262 // i.e. if next is non-NULL.
263 T next_oop = oopDesc::load_heap_oop(next_addr);
264 if (!oopDesc::is_null(next_oop)) { // i.e. ref is not "active"
265 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
266 debug_only(
267 if(TraceReferenceGC && PrintGCDetails) {
268 gclog_or_tty->print_cr(" Process discovered as normal "
269 PTR_FORMAT, p2i(discovered_addr));
270 }
271 )
272 cm->mark_and_push(discovered_addr);
273 }
274 } else {
275 #ifdef ASSERT
276 // In the case of older JDKs which do not use the discovered
277 // field for the pending list, an inactive ref (next != NULL)
278 // must always have a NULL discovered field.
279 T next = oopDesc::load_heap_oop(next_addr);
280 oop discovered = java_lang_ref_Reference::discovered(obj);
281 assert(oopDesc::is_null(next) || oopDesc::is_null(discovered),
282 err_msg("Found an inactive reference " PTR_FORMAT " with a non-NULL discovered field",
283 p2i(obj)));
284 #endif
285 }
286 cm->mark_and_push(next_addr);
287 klass->InstanceKlass::oop_pc_follow_contents(obj, cm);
288 }
289
290
291 void InstanceRefKlass::oop_pc_follow_contents(oop obj, ParCompactionManager* cm) {
292 if (UseCompressedOops) {
293 oop_pc_follow_contents_specialized<narrowOop>(this, obj, cm);
294 } else {
295 oop_pc_follow_contents_specialized<oop>(this, obj, cm);
296 }
297 }
298
299 void ObjArrayKlass::oop_pc_follow_contents(oop obj, ParCompactionManager* cm) {
300 cm->follow_klass(this);
301
302 if (UseCompressedOops) {
303 oop_pc_follow_contents_specialized<narrowOop>(objArrayOop(obj), 0, cm);
304 } else {
305 oop_pc_follow_contents_specialized<oop>(objArrayOop(obj), 0, cm);
306 }
307 }
308
309 void TypeArrayKlass::oop_pc_follow_contents(oop obj, ParCompactionManager* cm) {
310 assert(obj->is_typeArray(),"must be a type array");
311 // Performance tweak: We skip iterating over the klass pointer since we
312 // know that Universe::TypeArrayKlass never moves.
313 }
314
315 void ParCompactionManager::follow_marking_stacks() {
316 do {
317 // Drain the overflow stack first, to allow stealing from the marking stack.
318 oop obj;
319 while (marking_stack()->pop_overflow(obj)) {
320 follow_contents(obj);
321 }
322 while (marking_stack()->pop_local(obj)) {
323 follow_contents(obj);
324 }
325
326 // Process ObjArrays one at a time to avoid marking stack bloat.
327 ObjArrayTask task;
328 if (_objarray_stack.pop_overflow(task) || _objarray_stack.pop_local(task)) {
329 follow_contents((objArrayOop)task.obj(), task.index());
330 }
331 } while (!marking_stacks_empty());
332
333 assert(marking_stacks_empty(), "Sanity");
334 }
335
336 void ParCompactionManager::drain_region_stacks() {
337 do {
338 // Drain overflow stack first so other threads can steal.
339 size_t region_index;
340 while (region_stack()->pop_overflow(region_index)) {
341 PSParallelCompact::fill_and_update_region(this, region_index);
342 }
343
344 while (region_stack()->pop_local(region_index)) {
345 PSParallelCompact::fill_and_update_region(this, region_index);
346 }
347 } while (!region_stack()->is_empty());
348 }