1 /*
2 * Copyright (c) 2002, 2014, 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 "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
27 #include "gc_implementation/parallelScavenge/psOldGen.hpp"
28 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
29 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
30 #include "gc_implementation/shared/gcTrace.hpp"
31 #include "gc_implementation/shared/mutableSpace.hpp"
32 #include "memory/allocation.inline.hpp"
33 #include "memory/memRegion.hpp"
34 #include "memory/padded.inline.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "oops/oop.psgc.inline.hpp"
37
38 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
39
40 PaddedEnd<PSPromotionManager>* PSPromotionManager::_manager_array = NULL;
41 OopStarTaskQueueSet* PSPromotionManager::_stack_array_depth = NULL;
42 PSOldGen* PSPromotionManager::_old_gen = NULL;
43 MutableSpace* PSPromotionManager::_young_space = NULL;
44
45 void PSPromotionManager::initialize() {
46 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
47 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
48
49 _old_gen = heap->old_gen();
50 _young_space = heap->young_gen()->to_space();
51
52 // To prevent false sharing, we pad the PSPromotionManagers
53 // and make sure that the first instance starts at a cache line.
54 assert(_manager_array == NULL, "Attempt to initialize twice");
55 _manager_array = PaddedArray<PSPromotionManager, mtGC>::create_unfreeable(ParallelGCThreads + 1);
56 guarantee(_manager_array != NULL, "Could not initialize promotion manager");
57
58 _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads);
59 guarantee(_stack_array_depth != NULL, "Could not initialize promotion manager");
60
61 // Create and register the PSPromotionManager(s) for the worker threads.
62 for(uint i=0; i<ParallelGCThreads; i++) {
63 stack_array_depth()->register_queue(i, _manager_array[i].claimed_stack_depth());
64 }
65 // The VMThread gets its own PSPromotionManager, which is not available
66 // for work stealing.
67 }
68
69 PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(int index) {
70 assert(index >= 0 && index < (int)ParallelGCThreads, "index out of range");
71 assert(_manager_array != NULL, "Sanity");
72 return &_manager_array[index];
73 }
74
75 PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() {
76 assert(_manager_array != NULL, "Sanity");
77 return &_manager_array[ParallelGCThreads];
78 }
79
80 void PSPromotionManager::pre_scavenge() {
81 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
82 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
83
84 _young_space = heap->young_gen()->to_space();
85
86 for(uint i=0; i<ParallelGCThreads+1; i++) {
87 manager_array(i)->reset();
88 }
89 }
90
91 bool PSPromotionManager::post_scavenge(YoungGCTracer& gc_tracer) {
92 bool promotion_failure_occurred = false;
93
94 TASKQUEUE_STATS_ONLY(if (PrintTaskqueue) print_taskqueue_stats());
95 for (uint i = 0; i < ParallelGCThreads + 1; i++) {
96 PSPromotionManager* manager = manager_array(i);
97 assert(manager->claimed_stack_depth()->is_empty(), "should be empty");
98 if (manager->_promotion_failed_info.has_failed()) {
99 gc_tracer.report_promotion_failed(manager->_promotion_failed_info);
100 promotion_failure_occurred = true;
101 }
102 manager->flush_labs();
103 }
104 return promotion_failure_occurred;
105 }
106
107 #if TASKQUEUE_STATS
108 void
109 PSPromotionManager::print_local_stats(outputStream* const out, uint i) const {
110 #define FMT " " SIZE_FORMAT_W(10)
111 out->print_cr("%3u" FMT FMT FMT FMT, i, _masked_pushes, _masked_steals,
112 _arrays_chunked, _array_chunks_processed);
113 #undef FMT
114 }
115
116 static const char* const pm_stats_hdr[] = {
117 " --------masked------- arrays array",
118 "thr push steal chunked chunks",
119 "--- ---------- ---------- ---------- ----------"
120 };
121
122 void
123 PSPromotionManager::print_taskqueue_stats(outputStream* const out) {
124 out->print_cr("== GC Tasks Stats, GC %3d",
125 Universe::heap()->total_collections());
126
127 TaskQueueStats totals;
128 out->print("thr "); TaskQueueStats::print_header(1, out); out->cr();
129 out->print("--- "); TaskQueueStats::print_header(2, out); out->cr();
130 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
131 TaskQueueStats& next = manager_array(i)->_claimed_stack_depth.stats;
132 out->print("%3d ", i); next.print(out); out->cr();
133 totals += next;
134 }
135 out->print("tot "); totals.print(out); out->cr();
136
137 const uint hlines = sizeof(pm_stats_hdr) / sizeof(pm_stats_hdr[0]);
138 for (uint i = 0; i < hlines; ++i) out->print_cr("%s", pm_stats_hdr[i]);
139 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
140 manager_array(i)->print_local_stats(out, i);
141 }
142 }
143
144 void
145 PSPromotionManager::reset_stats() {
146 claimed_stack_depth()->stats.reset();
147 _masked_pushes = _masked_steals = 0;
148 _arrays_chunked = _array_chunks_processed = 0;
149 }
150 #endif // TASKQUEUE_STATS
151
152 PSPromotionManager::PSPromotionManager() {
153 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
154 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
155
156 // We set the old lab's start array.
157 _old_lab.set_start_array(old_gen()->start_array());
158
159 uint queue_size;
160 claimed_stack_depth()->initialize();
161 queue_size = claimed_stack_depth()->max_elems();
162
163 _totally_drain = (ParallelGCThreads == 1) || (GCDrainStackTargetSize == 0);
164 if (_totally_drain) {
165 _target_stack_size = 0;
166 } else {
167 // don't let the target stack size to be more than 1/4 of the entries
168 _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize,
169 (uint) (queue_size / 4));
170 }
171
172 _array_chunk_size = ParGCArrayScanChunk;
173 // let's choose 1.5x the chunk size
174 _min_array_size_for_chunking = 3 * _array_chunk_size / 2;
175
176 reset();
177 }
178
179 void PSPromotionManager::reset() {
180 assert(stacks_empty(), "reset of non-empty stack");
181
182 // We need to get an assert in here to make sure the labs are always flushed.
183
184 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
185 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
186
187 // Do not prefill the LAB's, save heap wastage!
188 HeapWord* lab_base = young_space()->top();
189 _young_lab.initialize(MemRegion(lab_base, (size_t)0));
190 _young_gen_is_full = false;
191
192 lab_base = old_gen()->object_space()->top();
193 _old_lab.initialize(MemRegion(lab_base, (size_t)0));
194 _old_gen_is_full = false;
195
196 _promotion_failed_info.reset();
197
198 TASKQUEUE_STATS_ONLY(reset_stats());
199 }
200
201
202 void PSPromotionManager::drain_stacks_depth(bool totally_drain) {
203 totally_drain = totally_drain || _totally_drain;
204
205 #ifdef ASSERT
206 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
207 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
208 MutableSpace* to_space = heap->young_gen()->to_space();
209 MutableSpace* old_space = heap->old_gen()->object_space();
210 #endif /* ASSERT */
211
212 OopStarTaskQueue* const tq = claimed_stack_depth();
213 do {
214 StarTask p;
215
216 // Drain overflow stack first, so other threads can steal from
217 // claimed stack while we work.
218 while (tq->pop_overflow(p)) {
219 process_popped_location_depth(p);
220 }
221
222 if (totally_drain) {
223 while (tq->pop_local(p)) {
224 process_popped_location_depth(p);
225 }
226 } else {
227 while (tq->size() > _target_stack_size && tq->pop_local(p)) {
228 process_popped_location_depth(p);
229 }
230 }
231 } while (totally_drain && !tq->taskqueue_empty() || !tq->overflow_empty());
232
233 assert(!totally_drain || tq->taskqueue_empty(), "Sanity");
234 assert(totally_drain || tq->size() <= _target_stack_size, "Sanity");
235 assert(tq->overflow_empty(), "Sanity");
236 }
237
238 void PSPromotionManager::flush_labs() {
239 assert(stacks_empty(), "Attempt to flush lab with live stack");
240
241 // If either promotion lab fills up, we can flush the
242 // lab but not refill it, so check first.
243 assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity");
244 if (!_young_lab.is_flushed())
245 _young_lab.flush();
246
247 assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity");
248 if (!_old_lab.is_flushed())
249 _old_lab.flush();
250
251 // Let PSScavenge know if we overflowed
252 if (_young_gen_is_full) {
253 PSScavenge::set_survivor_overflow(true);
254 }
255 }
256
257 template <class T> void PSPromotionManager::process_array_chunk_work(
258 oop obj,
259 int start, int end) {
260 assert(start <= end, "invariant");
261 T* const base = (T*)objArrayOop(obj)->base();
262 T* p = base + start;
263 T* const chunk_end = base + end;
264 while (p < chunk_end) {
265 if (PSScavenge::should_scavenge(p)) {
266 claim_or_forward_depth(p);
267 }
268 ++p;
269 }
270 }
271
272 void PSPromotionManager::process_array_chunk(oop old) {
273 assert(PSChunkLargeArrays, "invariant");
274 assert(old->is_objArray(), "invariant");
275 assert(old->is_forwarded(), "invariant");
276
277 TASKQUEUE_STATS_ONLY(++_array_chunks_processed);
278
279 oop const obj = old->forwardee();
280
281 int start;
282 int const end = arrayOop(old)->length();
283 if (end > (int) _min_array_size_for_chunking) {
284 // we'll chunk more
285 start = end - _array_chunk_size;
286 assert(start > 0, "invariant");
287 arrayOop(old)->set_length(start);
288 push_depth(mask_chunked_array_oop(old));
289 TASKQUEUE_STATS_ONLY(++_masked_pushes);
290 } else {
291 // this is the final chunk for this array
292 start = 0;
293 int const actual_length = arrayOop(obj)->length();
294 arrayOop(old)->set_length(actual_length);
295 }
296
297 if (UseCompressedOops) {
298 process_array_chunk_work<narrowOop>(obj, start, end);
299 } else {
300 process_array_chunk_work<oop>(obj, start, end);
301 }
302 }
303
304 oop PSPromotionManager::oop_promotion_failed(oop obj, markOop obj_mark) {
305 assert(_old_gen_is_full || PromotionFailureALot, "Sanity");
306
307 // Attempt to CAS in the header.
308 // This tests if the header is still the same as when
309 // this started. If it is the same (i.e., no forwarding
310 // pointer has been installed), then this thread owns
311 // it.
312 if (obj->cas_forward_to(obj, obj_mark)) {
313 // We won any races, we "own" this object.
314 assert(obj == obj->forwardee(), "Sanity");
315
316 _promotion_failed_info.register_copy_failure(obj->size());
317
318 obj->push_contents(this);
319
320 // Save the mark if needed
321 PSScavenge::oop_promotion_failed(obj, obj_mark);
322 } else {
323 // We lost, someone else "owns" this object
324 guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed.");
325
326 // No unallocation to worry about.
327 obj = obj->forwardee();
328 }
329
330 #ifndef PRODUCT
331 if (TraceScavenge) {
332 gclog_or_tty->print_cr("{%s %s " PTR_FORMAT " (%d)}",
333 "promotion-failure",
334 obj->klass()->internal_name(),
335 (void *)obj, obj->size());
336
337 }
338 #endif
339
340 return obj;
341 }