1 /*
2 * Copyright (c) 2002, 2018, 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/javaClasses.inline.hpp"
27 #include "gc/parallel/gcTaskManager.hpp"
28 #include "gc/parallel/mutableSpace.hpp"
29 #include "gc/parallel/parallelScavengeHeap.hpp"
30 #include "gc/parallel/psOldGen.hpp"
31 #include "gc/parallel/psPromotionManager.inline.hpp"
32 #include "gc/parallel/psScavenge.inline.hpp"
33 #include "gc/shared/gcTrace.hpp"
34 #include "gc/shared/preservedMarks.inline.hpp"
35 #include "gc/shared/taskqueue.inline.hpp"
36 #include "logging/log.hpp"
37 #include "logging/logStream.hpp"
38 #include "memory/allocation.inline.hpp"
39 #include "memory/iterator.inline.hpp"
40 #include "memory/memRegion.hpp"
41 #include "memory/padded.inline.hpp"
42 #include "memory/resourceArea.hpp"
43 #include "oops/access.inline.hpp"
44 #include "oops/compressedOops.inline.hpp"
45
46 PaddedEnd<PSPromotionManager>* PSPromotionManager::_manager_array = NULL;
47 OopStarTaskQueueSet* PSPromotionManager::_stack_array_depth = NULL;
48 PreservedMarksSet* PSPromotionManager::_preserved_marks_set = NULL;
49 PSOldGen* PSPromotionManager::_old_gen = NULL;
50 MutableSpace* PSPromotionManager::_young_space = NULL;
51
52 void PSPromotionManager::initialize() {
53 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
54
55 _old_gen = heap->old_gen();
56 _young_space = heap->young_gen()->to_space();
57
58 const uint promotion_manager_num = ParallelGCThreads + 1;
59
60 // To prevent false sharing, we pad the PSPromotionManagers
61 // and make sure that the first instance starts at a cache line.
62 assert(_manager_array == NULL, "Attempt to initialize twice");
63 _manager_array = PaddedArray<PSPromotionManager, mtGC>::create_unfreeable(promotion_manager_num);
64 guarantee(_manager_array != NULL, "Could not initialize promotion manager");
65
66 _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads);
67 guarantee(_stack_array_depth != NULL, "Could not initialize promotion manager");
68
69 // Create and register the PSPromotionManager(s) for the worker threads.
70 for(uint i=0; i<ParallelGCThreads; i++) {
71 stack_array_depth()->register_queue(i, _manager_array[i].claimed_stack_depth());
72 }
73 // The VMThread gets its own PSPromotionManager, which is not available
74 // for work stealing.
75
76 assert(_preserved_marks_set == NULL, "Attempt to initialize twice");
77 _preserved_marks_set = new PreservedMarksSet(true /* in_c_heap */);
78 guarantee(_preserved_marks_set != NULL, "Could not initialize preserved marks set");
79 _preserved_marks_set->init(promotion_manager_num);
80 for (uint i = 0; i < promotion_manager_num; i += 1) {
81 _manager_array[i].register_preserved_marks(_preserved_marks_set->get(i));
82 }
83 }
84
85 // Helper functions to get around the circular dependency between
86 // psScavenge.inline.hpp and psPromotionManager.inline.hpp.
87 bool PSPromotionManager::should_scavenge(oop* p, bool check_to_space) {
88 return PSScavenge::should_scavenge(p, check_to_space);
89 }
90 bool PSPromotionManager::should_scavenge(narrowOop* p, bool check_to_space) {
91 return PSScavenge::should_scavenge(p, check_to_space);
92 }
93
94 PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(uint index) {
95 assert(index < ParallelGCThreads, "index out of range");
96 assert(_manager_array != NULL, "Sanity");
97 return &_manager_array[index];
98 }
99
100 PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() {
101 assert(_manager_array != NULL, "Sanity");
102 return &_manager_array[ParallelGCThreads];
103 }
104
105 void PSPromotionManager::pre_scavenge() {
106 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
107
108 _preserved_marks_set->assert_empty();
109 _young_space = heap->young_gen()->to_space();
110
111 for(uint i=0; i<ParallelGCThreads+1; i++) {
112 manager_array(i)->reset();
113 }
114 }
115
116 bool PSPromotionManager::post_scavenge(YoungGCTracer& gc_tracer) {
117 bool promotion_failure_occurred = false;
118
119 TASKQUEUE_STATS_ONLY(print_taskqueue_stats());
120 for (uint i = 0; i < ParallelGCThreads + 1; i++) {
121 PSPromotionManager* manager = manager_array(i);
122 assert(manager->claimed_stack_depth()->is_empty(), "should be empty");
123 if (manager->_promotion_failed_info.has_failed()) {
124 gc_tracer.report_promotion_failed(manager->_promotion_failed_info);
125 promotion_failure_occurred = true;
126 }
127 manager->flush_labs();
128 }
129 if (!promotion_failure_occurred) {
130 // If there was no promotion failure, the preserved mark stacks
131 // should be empty.
132 _preserved_marks_set->assert_empty();
133 }
134 return promotion_failure_occurred;
135 }
136
137 #if TASKQUEUE_STATS
138 void
139 PSPromotionManager::print_local_stats(outputStream* const out, uint i) const {
140 #define FMT " " SIZE_FORMAT_W(10)
141 out->print_cr("%3u" FMT FMT FMT FMT, i, _masked_pushes, _masked_steals,
142 _arrays_chunked, _array_chunks_processed);
143 #undef FMT
144 }
145
146 static const char* const pm_stats_hdr[] = {
147 " --------masked------- arrays array",
148 "thr push steal chunked chunks",
149 "--- ---------- ---------- ---------- ----------"
150 };
151
152 void
153 PSPromotionManager::print_taskqueue_stats() {
154 if (!log_is_enabled(Trace, gc, task, stats)) {
155 return;
156 }
157 Log(gc, task, stats) log;
158 ResourceMark rm;
159 LogStream ls(log.trace());
160 outputStream* out = &ls;
161 out->print_cr("== GC Tasks Stats, GC %3d",
162 ParallelScavengeHeap::heap()->total_collections());
163
164 TaskQueueStats totals;
165 out->print("thr "); TaskQueueStats::print_header(1, out); out->cr();
166 out->print("--- "); TaskQueueStats::print_header(2, out); out->cr();
167 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
168 TaskQueueStats& next = manager_array(i)->_claimed_stack_depth.stats;
169 out->print("%3d ", i); next.print(out); out->cr();
170 totals += next;
171 }
172 out->print("tot "); totals.print(out); out->cr();
173
174 const uint hlines = sizeof(pm_stats_hdr) / sizeof(pm_stats_hdr[0]);
175 for (uint i = 0; i < hlines; ++i) out->print_cr("%s", pm_stats_hdr[i]);
176 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
177 manager_array(i)->print_local_stats(out, i);
178 }
179 }
180
181 void
182 PSPromotionManager::reset_stats() {
183 claimed_stack_depth()->stats.reset();
184 _masked_pushes = _masked_steals = 0;
185 _arrays_chunked = _array_chunks_processed = 0;
186 }
187 #endif // TASKQUEUE_STATS
188
189 PSPromotionManager::PSPromotionManager() {
190 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
191
192 // We set the old lab's start array.
193 _old_lab.set_start_array(old_gen()->start_array());
194
195 uint queue_size;
196 claimed_stack_depth()->initialize();
197 queue_size = claimed_stack_depth()->max_elems();
198
199 _totally_drain = (ParallelGCThreads == 1) || (GCDrainStackTargetSize == 0);
200 if (_totally_drain) {
201 _target_stack_size = 0;
202 } else {
203 // don't let the target stack size to be more than 1/4 of the entries
204 _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize,
205 (uint) (queue_size / 4));
206 }
207
208 _array_chunk_size = ParGCArrayScanChunk;
209 // let's choose 1.5x the chunk size
210 _min_array_size_for_chunking = 3 * _array_chunk_size / 2;
211
212 _preserved_marks = NULL;
213
214 reset();
215 }
216
217 void PSPromotionManager::reset() {
218 assert(stacks_empty(), "reset of non-empty stack");
219
220 // We need to get an assert in here to make sure the labs are always flushed.
221
222 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
223
224 // Do not prefill the LAB's, save heap wastage!
225 HeapWord* lab_base = young_space()->top();
226 _young_lab.initialize(MemRegion(lab_base, (size_t)0));
227 _young_gen_is_full = false;
228
229 lab_base = old_gen()->object_space()->top();
230 _old_lab.initialize(MemRegion(lab_base, (size_t)0));
231 _old_gen_is_full = false;
232
233 _promotion_failed_info.reset();
234
235 TASKQUEUE_STATS_ONLY(reset_stats());
236 }
237
238 void PSPromotionManager::register_preserved_marks(PreservedMarks* preserved_marks) {
239 assert(_preserved_marks == NULL, "do not set it twice");
240 _preserved_marks = preserved_marks;
241 }
242
243 class ParRestoreGCTask : public GCTask {
244 private:
245 const uint _id;
246 PreservedMarksSet* const _preserved_marks_set;
247 volatile size_t* const _total_size_addr;
248
249 public:
250 virtual char* name() {
251 return (char*) "preserved mark restoration task";
252 }
253
254 virtual void do_it(GCTaskManager* manager, uint which){
255 _preserved_marks_set->get(_id)->restore_and_increment(_total_size_addr);
256 }
257
258 ParRestoreGCTask(uint id,
259 PreservedMarksSet* preserved_marks_set,
260 volatile size_t* total_size_addr)
261 : _id(id),
262 _preserved_marks_set(preserved_marks_set),
263 _total_size_addr(total_size_addr) { }
264 };
265
266 class PSRestorePreservedMarksTaskExecutor : public RestorePreservedMarksTaskExecutor {
267 private:
268 GCTaskManager* _gc_task_manager;
269
270 public:
271 PSRestorePreservedMarksTaskExecutor(GCTaskManager* gc_task_manager)
272 : _gc_task_manager(gc_task_manager) { }
273
274 void restore(PreservedMarksSet* preserved_marks_set,
275 volatile size_t* total_size_addr) {
276 // GCTask / GCTaskQueue are ResourceObjs
277 ResourceMark rm;
278
279 GCTaskQueue* q = GCTaskQueue::create();
280 for (uint i = 0; i < preserved_marks_set->num(); i += 1) {
281 q->enqueue(new ParRestoreGCTask(i, preserved_marks_set, total_size_addr));
282 }
283 _gc_task_manager->execute_and_wait(q);
284 }
285 };
286
287 void PSPromotionManager::restore_preserved_marks() {
288 PSRestorePreservedMarksTaskExecutor task_executor(PSScavenge::gc_task_manager());
289 _preserved_marks_set->restore(&task_executor);
290 }
291
292 void PSPromotionManager::drain_stacks_depth(bool totally_drain) {
293 totally_drain = totally_drain || _totally_drain;
294
295 #ifdef ASSERT
296 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
297 MutableSpace* to_space = heap->young_gen()->to_space();
298 MutableSpace* old_space = heap->old_gen()->object_space();
299 #endif /* ASSERT */
300
301 OopStarTaskQueue* const tq = claimed_stack_depth();
302 do {
303 StarTask p;
304
305 // Drain overflow stack first, so other threads can steal from
306 // claimed stack while we work.
307 while (tq->pop_overflow(p)) {
308 process_popped_location_depth(p);
309 }
310
311 if (totally_drain) {
312 while (tq->pop_local(p)) {
313 process_popped_location_depth(p);
314 }
315 } else {
316 while (tq->size() > _target_stack_size && tq->pop_local(p)) {
317 process_popped_location_depth(p);
318 }
319 }
320 } while ((totally_drain && !tq->taskqueue_empty()) || !tq->overflow_empty());
321
322 assert(!totally_drain || tq->taskqueue_empty(), "Sanity");
323 assert(totally_drain || tq->size() <= _target_stack_size, "Sanity");
324 assert(tq->overflow_empty(), "Sanity");
325 }
326
327 void PSPromotionManager::flush_labs() {
328 assert(stacks_empty(), "Attempt to flush lab with live stack");
329
330 // If either promotion lab fills up, we can flush the
331 // lab but not refill it, so check first.
332 assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity");
333 if (!_young_lab.is_flushed())
334 _young_lab.flush();
335
336 assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity");
337 if (!_old_lab.is_flushed())
338 _old_lab.flush();
339
340 // Let PSScavenge know if we overflowed
341 if (_young_gen_is_full) {
342 PSScavenge::set_survivor_overflow(true);
343 }
344 }
345
346 template <class T> void PSPromotionManager::process_array_chunk_work(
347 oop obj,
348 int start, int end) {
349 assert(start <= end, "invariant");
350 T* const base = (T*)objArrayOop(obj)->base();
351 T* p = base + start;
352 T* const chunk_end = base + end;
353 while (p < chunk_end) {
354 if (PSScavenge::should_scavenge(p)) {
355 claim_or_forward_depth(p);
356 }
357 ++p;
358 }
359 }
360
361 void PSPromotionManager::process_array_chunk(oop old) {
362 assert(PSChunkLargeArrays, "invariant");
363 assert(old->is_objArray(), "invariant");
364 assert(old->is_forwarded(), "invariant");
365
366 TASKQUEUE_STATS_ONLY(++_array_chunks_processed);
367
368 oop const obj = old->forwardee();
369
370 int start;
371 int const end = arrayOop(old)->length();
372 if (end > (int) _min_array_size_for_chunking) {
373 // we'll chunk more
374 start = end - _array_chunk_size;
375 assert(start > 0, "invariant");
376 arrayOop(old)->set_length(start);
377 push_depth(mask_chunked_array_oop(old));
378 TASKQUEUE_STATS_ONLY(++_masked_pushes);
379 } else {
380 // this is the final chunk for this array
381 start = 0;
382 int const actual_length = arrayOop(obj)->length();
383 arrayOop(old)->set_length(actual_length);
384 }
385
386 if (UseCompressedOops) {
387 process_array_chunk_work<narrowOop>(obj, start, end);
388 } else {
389 process_array_chunk_work<oop>(obj, start, end);
390 }
391 }
392
393 oop PSPromotionManager::oop_promotion_failed(oop obj, markOop obj_mark) {
394 assert(_old_gen_is_full || PromotionFailureALot, "Sanity");
395
396 // Attempt to CAS in the header.
397 // This tests if the header is still the same as when
398 // this started. If it is the same (i.e., no forwarding
399 // pointer has been installed), then this thread owns
400 // it.
401 if (obj->cas_forward_to(obj, obj_mark)) {
402 // We won any races, we "own" this object.
403 assert(obj == obj->forwardee(), "Sanity");
404
405 _promotion_failed_info.register_copy_failure(obj->size());
406
407 push_contents(obj);
408
409 _preserved_marks->push_if_necessary(obj, obj_mark);
410 } else {
411 // We lost, someone else "owns" this object
412 guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed.");
413
414 // No unallocation to worry about.
415 obj = obj->forwardee();
416 }
417
418 log_develop_trace(gc, scavenge)("{promotion-failure %s " PTR_FORMAT " (%d)}", obj->klass()->internal_name(), p2i(obj), obj->size());
419
420 return obj;
421 }