1 /*
2 * Copyright (c) 2002, 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 "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 "utilities/stack.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 // Helper functions to get around the circular dependency between
70 // psScavenge.inline.hpp and psPromotionManager.inline.hpp.
71 bool PSPromotionManager::should_scavenge(oop* p, bool check_to_space) {
72 return PSScavenge::should_scavenge(p, check_to_space);
73 }
74 bool PSPromotionManager::should_scavenge(narrowOop* p, bool check_to_space) {
75 return PSScavenge::should_scavenge(p, check_to_space);
76 }
77
78 PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(int index) {
79 assert(index >= 0 && index < (int)ParallelGCThreads, "index out of range");
80 assert(_manager_array != NULL, "Sanity");
81 return &_manager_array[index];
82 }
83
84 PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() {
85 assert(_manager_array != NULL, "Sanity");
86 return &_manager_array[ParallelGCThreads];
87 }
88
89 void PSPromotionManager::pre_scavenge() {
90 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
91 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
92
93 _young_space = heap->young_gen()->to_space();
94
95 for(uint i=0; i<ParallelGCThreads+1; i++) {
96 manager_array(i)->reset();
97 }
98 }
99
100 bool PSPromotionManager::post_scavenge(YoungGCTracer& gc_tracer) {
101 bool promotion_failure_occurred = false;
102
103 TASKQUEUE_STATS_ONLY(if (PrintTaskqueue) print_taskqueue_stats());
104 for (uint i = 0; i < ParallelGCThreads + 1; i++) {
105 PSPromotionManager* manager = manager_array(i);
106 assert(manager->claimed_stack_depth()->is_empty(), "should be empty");
107 if (manager->_promotion_failed_info.has_failed()) {
108 gc_tracer.report_promotion_failed(manager->_promotion_failed_info);
109 promotion_failure_occurred = true;
110 }
111 manager->flush_labs();
112 }
113 return promotion_failure_occurred;
114 }
115
116 #if TASKQUEUE_STATS
117 void
118 PSPromotionManager::print_local_stats(outputStream* const out, uint i) const {
119 #define FMT " " SIZE_FORMAT_W(10)
120 out->print_cr("%3u" FMT FMT FMT FMT, i, _masked_pushes, _masked_steals,
121 _arrays_chunked, _array_chunks_processed);
122 #undef FMT
123 }
124
125 static const char* const pm_stats_hdr[] = {
126 " --------masked------- arrays array",
127 "thr push steal chunked chunks",
128 "--- ---------- ---------- ---------- ----------"
129 };
130
131 void
132 PSPromotionManager::print_taskqueue_stats(outputStream* const out) {
133 out->print_cr("== GC Tasks Stats, GC %3d",
134 Universe::heap()->total_collections());
135
136 TaskQueueStats totals;
137 out->print("thr "); TaskQueueStats::print_header(1, out); out->cr();
138 out->print("--- "); TaskQueueStats::print_header(2, out); out->cr();
139 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
140 TaskQueueStats& next = manager_array(i)->_claimed_stack_depth.stats;
141 out->print("%3d ", i); next.print(out); out->cr();
142 totals += next;
143 }
144 out->print("tot "); totals.print(out); out->cr();
145
146 const uint hlines = sizeof(pm_stats_hdr) / sizeof(pm_stats_hdr[0]);
147 for (uint i = 0; i < hlines; ++i) out->print_cr("%s", pm_stats_hdr[i]);
148 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
149 manager_array(i)->print_local_stats(out, i);
150 }
151 }
152
153 void
154 PSPromotionManager::reset_stats() {
155 claimed_stack_depth()->stats.reset();
156 _masked_pushes = _masked_steals = 0;
157 _arrays_chunked = _array_chunks_processed = 0;
158 }
159 #endif // TASKQUEUE_STATS
160
161 PSPromotionManager::PSPromotionManager() {
162 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
163 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
164
165 // We set the old lab's start array.
166 _old_lab.set_start_array(old_gen()->start_array());
167
168 uint queue_size;
169 claimed_stack_depth()->initialize();
170 queue_size = claimed_stack_depth()->max_elems();
171
172 _totally_drain = (ParallelGCThreads == 1) || (GCDrainStackTargetSize == 0);
173 if (_totally_drain) {
174 _target_stack_size = 0;
175 } else {
176 // don't let the target stack size to be more than 1/4 of the entries
177 _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize,
178 (uint) (queue_size / 4));
179 }
180
181 _array_chunk_size = ParGCArrayScanChunk;
182 // let's choose 1.5x the chunk size
183 _min_array_size_for_chunking = 3 * _array_chunk_size / 2;
184
185 reset();
186 }
187
188 void PSPromotionManager::reset() {
189 assert(stacks_empty(), "reset of non-empty stack");
190
191 // We need to get an assert in here to make sure the labs are always flushed.
192
193 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
194 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
195
196 // Do not prefill the LAB's, save heap wastage!
197 HeapWord* lab_base = young_space()->top();
198 _young_lab.initialize(MemRegion(lab_base, (size_t)0));
199 _young_gen_is_full = false;
200
201 lab_base = old_gen()->object_space()->top();
202 _old_lab.initialize(MemRegion(lab_base, (size_t)0));
203 _old_gen_is_full = false;
204
205 _promotion_failed_info.reset();
206
207 TASKQUEUE_STATS_ONLY(reset_stats());
208 }
209
210
211 void PSPromotionManager::drain_stacks_depth(bool totally_drain) {
212 totally_drain = totally_drain || _totally_drain;
213
214 #ifdef ASSERT
215 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
216 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
217 MutableSpace* to_space = heap->young_gen()->to_space();
218 MutableSpace* old_space = heap->old_gen()->object_space();
219 #endif /* ASSERT */
220
221 OopStarTaskQueue* const tq = claimed_stack_depth();
222 do {
223 StarTask p;
224
225 // Drain overflow stack first, so other threads can steal from
226 // claimed stack while we work.
227 while (tq->pop_overflow(p)) {
228 process_popped_location_depth(p);
229 }
230
231 if (totally_drain) {
232 while (tq->pop_local(p)) {
233 process_popped_location_depth(p);
234 }
235 } else {
236 while (tq->size() > _target_stack_size && tq->pop_local(p)) {
237 process_popped_location_depth(p);
238 }
239 }
240 } while (totally_drain && !tq->taskqueue_empty() || !tq->overflow_empty());
241
242 assert(!totally_drain || tq->taskqueue_empty(), "Sanity");
243 assert(totally_drain || tq->size() <= _target_stack_size, "Sanity");
244 assert(tq->overflow_empty(), "Sanity");
245 }
246
247 void PSPromotionManager::flush_labs() {
248 assert(stacks_empty(), "Attempt to flush lab with live stack");
249
250 // If either promotion lab fills up, we can flush the
251 // lab but not refill it, so check first.
252 assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity");
253 if (!_young_lab.is_flushed())
254 _young_lab.flush();
255
256 assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity");
257 if (!_old_lab.is_flushed())
258 _old_lab.flush();
259
260 // Let PSScavenge know if we overflowed
261 if (_young_gen_is_full) {
262 PSScavenge::set_survivor_overflow(true);
263 }
264 }
265
266 template <class T> void PSPromotionManager::process_array_chunk_work(
267 oop obj,
268 int start, int end) {
269 assert(start <= end, "invariant");
270 T* const base = (T*)objArrayOop(obj)->base();
271 T* p = base + start;
272 T* const chunk_end = base + end;
273 while (p < chunk_end) {
274 if (PSScavenge::should_scavenge(p)) {
275 claim_or_forward_depth(p);
276 }
277 ++p;
278 }
279 }
280
281 void PSPromotionManager::process_array_chunk(oop old) {
282 assert(PSChunkLargeArrays, "invariant");
283 assert(old->is_objArray(), "invariant");
284 assert(old->is_forwarded(), "invariant");
285
286 TASKQUEUE_STATS_ONLY(++_array_chunks_processed);
287
288 oop const obj = old->forwardee();
289
290 int start;
291 int const end = arrayOop(old)->length();
292 if (end > (int) _min_array_size_for_chunking) {
293 // we'll chunk more
294 start = end - _array_chunk_size;
295 assert(start > 0, "invariant");
296 arrayOop(old)->set_length(start);
297 push_depth(mask_chunked_array_oop(old));
298 TASKQUEUE_STATS_ONLY(++_masked_pushes);
299 } else {
300 // this is the final chunk for this array
301 start = 0;
302 int const actual_length = arrayOop(obj)->length();
303 arrayOop(old)->set_length(actual_length);
304 }
305
306 if (UseCompressedOops) {
307 process_array_chunk_work<narrowOop>(obj, start, end);
308 } else {
309 process_array_chunk_work<oop>(obj, start, end);
310 }
311 }
312
313 oop PSPromotionManager::oop_promotion_failed(oop obj, markOop obj_mark) {
314 assert(_old_gen_is_full || PromotionFailureALot, "Sanity");
315
316 // Attempt to CAS in the header.
317 // This tests if the header is still the same as when
318 // this started. If it is the same (i.e., no forwarding
319 // pointer has been installed), then this thread owns
320 // it.
321 if (obj->cas_forward_to(obj, obj_mark)) {
322 // We won any races, we "own" this object.
323 assert(obj == obj->forwardee(), "Sanity");
324
325 _promotion_failed_info.register_copy_failure(obj->size());
326
327 push_contents(obj);
328
329 // Save the mark if needed
330 PSScavenge::oop_promotion_failed(obj, obj_mark);
331 } else {
332 // We lost, someone else "owns" this object
333 guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed.");
334
335 // No unallocation to worry about.
336 obj = obj->forwardee();
337 }
338
339 #ifndef PRODUCT
340 if (TraceScavenge) {
341 gclog_or_tty->print_cr("{%s %s " PTR_FORMAT " (%d)}",
342 "promotion-failure",
343 obj->klass()->internal_name(),
344 (void *)obj, obj->size());
345
346 }
347 #endif
348
349 return obj;
350 }