1 /*
2 * Copyright (c) 2002, 2020, 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/mutableSpace.hpp"
28 #include "gc/parallel/parallelScavengeHeap.hpp"
29 #include "gc/parallel/psOldGen.hpp"
30 #include "gc/parallel/psPromotionManager.inline.hpp"
31 #include "gc/parallel/psScavenge.inline.hpp"
32 #include "gc/shared/gcTrace.hpp"
33 #include "gc/shared/preservedMarks.inline.hpp"
34 #include "gc/shared/taskqueue.inline.hpp"
35 #include "logging/log.hpp"
36 #include "logging/logStream.hpp"
37 #include "memory/allocation.inline.hpp"
38 #include "memory/iterator.inline.hpp"
39 #include "memory/memRegion.hpp"
40 #include "memory/padded.inline.hpp"
41 #include "memory/resourceArea.hpp"
42 #include "oops/access.inline.hpp"
43 #include "oops/compressedOops.inline.hpp"
44
45 PaddedEnd<PSPromotionManager>* PSPromotionManager::_manager_array = NULL;
46 PSPromotionManager::OopStarTaskQueueSet* PSPromotionManager::_stack_array_depth = NULL;
47 PreservedMarksSet* PSPromotionManager::_preserved_marks_set = NULL;
48 PSOldGen* PSPromotionManager::_old_gen = NULL;
49 MutableSpace* PSPromotionManager::_young_space = NULL;
50
51 void PSPromotionManager::initialize() {
52 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
53
54 _old_gen = heap->old_gen();
55 _young_space = heap->young_gen()->to_space();
56
57 const uint promotion_manager_num = ParallelGCThreads + 1;
58
59 // To prevent false sharing, we pad the PSPromotionManagers
60 // and make sure that the first instance starts at a cache line.
61 assert(_manager_array == NULL, "Attempt to initialize twice");
62 _manager_array = PaddedArray<PSPromotionManager, mtGC>::create_unfreeable(promotion_manager_num);
63
64 _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads);
65
66 // Create and register the PSPromotionManager(s) for the worker threads.
67 for(uint i=0; i<ParallelGCThreads; i++) {
68 stack_array_depth()->register_queue(i, _manager_array[i].claimed_stack_depth());
69 }
70 // The VMThread gets its own PSPromotionManager, which is not available
71 // for work stealing.
72
73 assert(_preserved_marks_set == NULL, "Attempt to initialize twice");
74 _preserved_marks_set = new PreservedMarksSet(true /* in_c_heap */);
75 _preserved_marks_set->init(promotion_manager_num);
76 for (uint i = 0; i < promotion_manager_num; i += 1) {
77 _manager_array[i].register_preserved_marks(_preserved_marks_set->get(i));
78 }
79 }
80
81 // Helper functions to get around the circular dependency between
82 // psScavenge.inline.hpp and psPromotionManager.inline.hpp.
83 bool PSPromotionManager::should_scavenge(oop* p, bool check_to_space) {
84 return PSScavenge::should_scavenge(p, check_to_space);
85 }
86 bool PSPromotionManager::should_scavenge(narrowOop* p, bool check_to_space) {
87 return PSScavenge::should_scavenge(p, check_to_space);
88 }
89
90 PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(uint index) {
91 assert(index < ParallelGCThreads, "index out of range");
92 assert(_manager_array != NULL, "Sanity");
93 return &_manager_array[index];
94 }
95
96 PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() {
97 assert(_manager_array != NULL, "Sanity");
98 return &_manager_array[ParallelGCThreads];
99 }
100
101 void PSPromotionManager::pre_scavenge() {
102 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
103
104 _preserved_marks_set->assert_empty();
105 _young_space = heap->young_gen()->to_space();
106
107 for(uint i=0; i<ParallelGCThreads+1; i++) {
108 manager_array(i)->reset();
109 }
110 }
111
112 bool PSPromotionManager::post_scavenge(YoungGCTracer& gc_tracer) {
113 bool promotion_failure_occurred = false;
114
115 TASKQUEUE_STATS_ONLY(print_taskqueue_stats());
116 for (uint i = 0; i < ParallelGCThreads + 1; i++) {
117 PSPromotionManager* manager = manager_array(i);
118 assert(manager->claimed_stack_depth()->is_empty(), "should be empty");
119 if (manager->_promotion_failed_info.has_failed()) {
120 gc_tracer.report_promotion_failed(manager->_promotion_failed_info);
121 promotion_failure_occurred = true;
122 }
123 manager->flush_labs();
124 }
125 if (!promotion_failure_occurred) {
126 // If there was no promotion failure, the preserved mark stacks
127 // should be empty.
128 _preserved_marks_set->assert_empty();
129 }
130 return promotion_failure_occurred;
131 }
132
133 #if TASKQUEUE_STATS
134 void
135 PSPromotionManager::print_local_stats(outputStream* const out, uint i) const {
136 #define FMT " " SIZE_FORMAT_W(10)
137 out->print_cr("%3u" FMT FMT FMT FMT, i, _masked_pushes, _masked_steals,
138 _arrays_chunked, _array_chunks_processed);
139 #undef FMT
140 }
141
142 static const char* const pm_stats_hdr[] = {
143 " --------masked------- arrays array",
144 "thr push steal chunked chunks",
145 "--- ---------- ---------- ---------- ----------"
146 };
147
148 void
149 PSPromotionManager::print_taskqueue_stats() {
150 if (!log_is_enabled(Trace, gc, task, stats)) {
151 return;
152 }
153 Log(gc, task, stats) log;
154 ResourceMark rm;
155 LogStream ls(log.trace());
156 outputStream* out = &ls;
157 out->print_cr("== GC Tasks Stats, GC %3d",
158 ParallelScavengeHeap::heap()->total_collections());
159
160 TaskQueueStats totals;
161 out->print("thr "); TaskQueueStats::print_header(1, out); out->cr();
162 out->print("--- "); TaskQueueStats::print_header(2, out); out->cr();
163 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
164 TaskQueueStats& next = manager_array(i)->_claimed_stack_depth.stats;
165 out->print("%3d ", i); next.print(out); out->cr();
166 totals += next;
167 }
168 out->print("tot "); totals.print(out); out->cr();
169
170 const uint hlines = sizeof(pm_stats_hdr) / sizeof(pm_stats_hdr[0]);
171 for (uint i = 0; i < hlines; ++i) out->print_cr("%s", pm_stats_hdr[i]);
172 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
173 manager_array(i)->print_local_stats(out, i);
174 }
175 }
176
177 void
178 PSPromotionManager::reset_stats() {
179 claimed_stack_depth()->stats.reset();
180 _masked_pushes = _masked_steals = 0;
181 _arrays_chunked = _array_chunks_processed = 0;
182 }
183 #endif // TASKQUEUE_STATS
184
185 PSPromotionManager::PSPromotionManager() {
186 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
187
188 // We set the old lab's start array.
189 _old_lab.set_start_array(old_gen()->start_array());
190
191 uint queue_size;
192 claimed_stack_depth()->initialize();
193 queue_size = claimed_stack_depth()->max_elems();
194
195 _totally_drain = (ParallelGCThreads == 1) || (GCDrainStackTargetSize == 0);
196 if (_totally_drain) {
197 _target_stack_size = 0;
198 } else {
199 // don't let the target stack size to be more than 1/4 of the entries
200 _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize,
201 (uint) (queue_size / 4));
202 }
203
204 _array_chunk_size = ParGCArrayScanChunk;
205 // let's choose 1.5x the chunk size
206 _min_array_size_for_chunking = 3 * _array_chunk_size / 2;
207
208 _preserved_marks = NULL;
209
210 reset();
211 }
212
213 void PSPromotionManager::reset() {
214 assert(stacks_empty(), "reset of non-empty stack");
215
216 // We need to get an assert in here to make sure the labs are always flushed.
217
218 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
219
220 // Do not prefill the LAB's, save heap wastage!
221 HeapWord* lab_base = young_space()->top();
222 _young_lab.initialize(MemRegion(lab_base, (size_t)0));
223 _young_gen_is_full = false;
224
225 lab_base = old_gen()->object_space()->top();
226 _old_lab.initialize(MemRegion(lab_base, (size_t)0));
227 _old_gen_is_full = false;
228
229 _promotion_failed_info.reset();
230
231 TASKQUEUE_STATS_ONLY(reset_stats());
232 }
233
234 void PSPromotionManager::register_preserved_marks(PreservedMarks* preserved_marks) {
235 assert(_preserved_marks == NULL, "do not set it twice");
236 _preserved_marks = preserved_marks;
237 }
238
239 void PSPromotionManager::restore_preserved_marks() {
240 _preserved_marks_set->restore(&ParallelScavengeHeap::heap()->workers());
241 }
242
243 void PSPromotionManager::drain_stacks_depth(bool totally_drain) {
244 totally_drain = totally_drain || _totally_drain;
245
246 #ifdef ASSERT
247 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
248 MutableSpace* to_space = heap->young_gen()->to_space();
249 MutableSpace* old_space = heap->old_gen()->object_space();
250 #endif /* ASSERT */
251
252 OopStarTaskQueue* const tq = claimed_stack_depth();
253 do {
254 StarTask p;
255
256 // Drain overflow stack first, so other threads can steal from
257 // claimed stack while we work.
258 while (tq->pop_overflow(p)) {
259 process_popped_location_depth(p);
260 }
261
262 if (totally_drain) {
263 while (tq->pop_local(p)) {
264 process_popped_location_depth(p);
265 }
266 } else {
267 while (tq->size() > _target_stack_size && tq->pop_local(p)) {
268 process_popped_location_depth(p);
269 }
270 }
271 } while ((totally_drain && !tq->taskqueue_empty()) || !tq->overflow_empty());
272
273 assert(!totally_drain || tq->taskqueue_empty(), "Sanity");
274 assert(totally_drain || tq->size() <= _target_stack_size, "Sanity");
275 assert(tq->overflow_empty(), "Sanity");
276 }
277
278 void PSPromotionManager::flush_labs() {
279 assert(stacks_empty(), "Attempt to flush lab with live stack");
280
281 // If either promotion lab fills up, we can flush the
282 // lab but not refill it, so check first.
283 assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity");
284 if (!_young_lab.is_flushed())
285 _young_lab.flush();
286
287 assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity");
288 if (!_old_lab.is_flushed())
289 _old_lab.flush();
290
291 // Let PSScavenge know if we overflowed
292 if (_young_gen_is_full) {
293 PSScavenge::set_survivor_overflow(true);
294 }
295 }
296
297 template <class T> void PSPromotionManager::process_array_chunk_work(
298 oop obj,
299 int start, int end) {
300 assert(start <= end, "invariant");
301 T* const base = (T*)objArrayOop(obj)->base();
302 T* p = base + start;
303 T* const chunk_end = base + end;
304 while (p < chunk_end) {
305 if (PSScavenge::should_scavenge(p)) {
306 claim_or_forward_depth(p);
307 }
308 ++p;
309 }
310 }
311
312 void PSPromotionManager::process_array_chunk(oop old) {
313 assert(PSChunkLargeArrays, "invariant");
314 assert(old->is_objArray(), "invariant");
315 assert(old->is_forwarded(), "invariant");
316
317 TASKQUEUE_STATS_ONLY(++_array_chunks_processed);
318
319 oop const obj = old->forwardee();
320
321 int start;
322 int const end = arrayOop(old)->length();
323 if (end > (int) _min_array_size_for_chunking) {
324 // we'll chunk more
325 start = end - _array_chunk_size;
326 assert(start > 0, "invariant");
327 arrayOop(old)->set_length(start);
328 push_depth(mask_chunked_array_oop(old));
329 TASKQUEUE_STATS_ONLY(++_masked_pushes);
330 } else {
331 // this is the final chunk for this array
332 start = 0;
333 int const actual_length = arrayOop(obj)->length();
334 arrayOop(old)->set_length(actual_length);
335 }
336
337 if (UseCompressedOops) {
338 process_array_chunk_work<narrowOop>(obj, start, end);
339 } else {
340 process_array_chunk_work<oop>(obj, start, end);
341 }
342 }
343
344 oop PSPromotionManager::oop_promotion_failed(oop obj, markWord obj_mark) {
345 assert(_old_gen_is_full || PromotionFailureALot, "Sanity");
346
347 // Attempt to CAS in the header.
348 // This tests if the header is still the same as when
349 // this started. If it is the same (i.e., no forwarding
350 // pointer has been installed), then this thread owns
351 // it.
352 if (obj->cas_forward_to(obj, obj_mark)) {
353 // We won any races, we "own" this object.
354 assert(obj == obj->forwardee(), "Sanity");
355
356 _promotion_failed_info.register_copy_failure(obj->size());
357
358 push_contents(obj);
359
360 _preserved_marks->push_if_necessary(obj, obj_mark);
361 } else {
362 // We lost, someone else "owns" this object
363 guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed.");
364
365 // No unallocation to worry about.
366 obj = obj->forwardee();
367 }
368
369 log_develop_trace(gc, scavenge)("{promotion-failure %s " PTR_FORMAT " (%d)}", obj->klass()->internal_name(), p2i(obj), obj->size());
370
371 return obj;
372 }