1 /*
2 * Copyright (c) 2002, 2016, 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/parallel/mutableSpace.hpp"
27 #include "gc/parallel/parallelScavengeHeap.hpp"
28 #include "gc/parallel/psOldGen.hpp"
29 #include "gc/parallel/psPromotionManager.inline.hpp"
30 #include "gc/parallel/psScavenge.inline.hpp"
31 #include "gc/shared/gcTrace.hpp"
32 #include "gc/shared/preservedMarks.inline.hpp"
33 #include "gc/shared/taskqueue.inline.hpp"
34 #include "logging/log.hpp"
35 #include "memory/allocation.inline.hpp"
36 #include "memory/memRegion.hpp"
37 #include "memory/padded.inline.hpp"
38 #include "memory/resourceArea.hpp"
39 #include "oops/instanceKlass.inline.hpp"
40 #include "oops/instanceMirrorKlass.inline.hpp"
41 #include "oops/objArrayKlass.inline.hpp"
42 #include "oops/oop.inline.hpp"
43
44 PaddedEnd<PSPromotionManager>* PSPromotionManager::_manager_array = NULL;
45 OopStarTaskQueueSet* PSPromotionManager::_stack_array_depth = NULL;
46 PreservedMarksSet* PSPromotionManager::_preserved_marks_set = NULL;
47 PSOldGen* PSPromotionManager::_old_gen = NULL;
48 MutableSpace* PSPromotionManager::_young_space = NULL;
49
50 void PSPromotionManager::initialize() {
51 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
52
53 _old_gen = heap->old_gen();
54 _young_space = heap->young_gen()->to_space();
55
56 const uint promotion_manager_num = ParallelGCThreads + 1;
57
58 // To prevent false sharing, we pad the PSPromotionManagers
59 // and make sure that the first instance starts at a cache line.
60 assert(_manager_array == NULL, "Attempt to initialize twice");
61 _manager_array = PaddedArray<PSPromotionManager, mtGC>::create_unfreeable(promotion_manager_num);
62 guarantee(_manager_array != NULL, "Could not initialize promotion manager");
63
64 _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads);
65 guarantee(_stack_array_depth != NULL, "Could not initialize promotion manager");
66
67 // Create and register the PSPromotionManager(s) for the worker threads.
68 for(uint i=0; i<ParallelGCThreads; i++) {
69 stack_array_depth()->register_queue(i, _manager_array[i].claimed_stack_depth());
70 }
71 // The VMThread gets its own PSPromotionManager, which is not available
72 // for work stealing.
73
74 assert(_preserved_marks_set == NULL, "Attempt to initialize twice");
75 _preserved_marks_set = new PreservedMarksSet(true /* in_c_heap */);
76 guarantee(_preserved_marks_set != NULL, "Could not initialize preserved marks set");
77 _preserved_marks_set->init(promotion_manager_num);
78 for (uint i = 0; i < promotion_manager_num; i += 1) {
79 _manager_array[i].register_preserved_marks(_preserved_marks_set->get(i));
80 }
81 }
82
83 // Helper functions to get around the circular dependency between
84 // psScavenge.inline.hpp and psPromotionManager.inline.hpp.
85 bool PSPromotionManager::should_scavenge(oop* p, bool check_to_space) {
86 return PSScavenge::should_scavenge(p, check_to_space);
87 }
88 bool PSPromotionManager::should_scavenge(narrowOop* p, bool check_to_space) {
89 return PSScavenge::should_scavenge(p, check_to_space);
90 }
91
92 PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(uint index) {
93 assert(index < ParallelGCThreads, "index out of range");
94 assert(_manager_array != NULL, "Sanity");
95 return &_manager_array[index];
96 }
97
98 PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() {
99 assert(_manager_array != NULL, "Sanity");
100 return &_manager_array[ParallelGCThreads];
101 }
102
103 void PSPromotionManager::pre_scavenge() {
104 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
105
106 _preserved_marks_set->assert_empty();
107 _young_space = heap->young_gen()->to_space();
108
109 for(uint i=0; i<ParallelGCThreads+1; i++) {
110 manager_array(i)->reset();
111 }
112 }
113
114 bool PSPromotionManager::post_scavenge(YoungGCTracer& gc_tracer) {
115 bool promotion_failure_occurred = false;
116
117 TASKQUEUE_STATS_ONLY(print_taskqueue_stats());
118 for (uint i = 0; i < ParallelGCThreads + 1; i++) {
119 PSPromotionManager* manager = manager_array(i);
120 assert(manager->claimed_stack_depth()->is_empty(), "should be empty");
121 if (manager->_promotion_failed_info.has_failed()) {
122 gc_tracer.report_promotion_failed(manager->_promotion_failed_info);
123 promotion_failure_occurred = true;
124 }
125 manager->flush_labs();
126 }
127 if (!promotion_failure_occurred) {
128 // If there was no promotion failure, the preserved mark stacks
129 // should be empty.
130 _preserved_marks_set->assert_empty();
131 }
132 return promotion_failure_occurred;
133 }
134
135 #if TASKQUEUE_STATS
136 void
137 PSPromotionManager::print_local_stats(outputStream* const out, uint i) const {
138 #define FMT " " SIZE_FORMAT_W(10)
139 out->print_cr("%3u" FMT FMT FMT FMT, i, _masked_pushes, _masked_steals,
140 _arrays_chunked, _array_chunks_processed);
141 #undef FMT
142 }
143
144 static const char* const pm_stats_hdr[] = {
145 " --------masked------- arrays array",
146 "thr push steal chunked chunks",
147 "--- ---------- ---------- ---------- ----------"
148 };
149
150 void
151 PSPromotionManager::print_taskqueue_stats() {
152 if (!log_develop_is_enabled(Trace, gc, task, stats)) {
153 return;
154 }
155 Log(gc, task, stats) log;
156 ResourceMark rm;
157 outputStream* out = log.trace_stream();
158 out->print_cr("== GC Tasks Stats, GC %3d",
159 ParallelScavengeHeap::heap()->total_collections());
160
161 TaskQueueStats totals;
162 out->print("thr "); TaskQueueStats::print_header(1, out); out->cr();
163 out->print("--- "); TaskQueueStats::print_header(2, out); out->cr();
164 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
165 TaskQueueStats& next = manager_array(i)->_claimed_stack_depth.stats;
166 out->print("%3d ", i); next.print(out); out->cr();
167 totals += next;
168 }
169 out->print("tot "); totals.print(out); out->cr();
170
171 const uint hlines = sizeof(pm_stats_hdr) / sizeof(pm_stats_hdr[0]);
172 for (uint i = 0; i < hlines; ++i) out->print_cr("%s", pm_stats_hdr[i]);
173 for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
174 manager_array(i)->print_local_stats(out, i);
175 }
176 }
177
178 void
179 PSPromotionManager::reset_stats() {
180 claimed_stack_depth()->stats.reset();
181 _masked_pushes = _masked_steals = 0;
182 _arrays_chunked = _array_chunks_processed = 0;
183 }
184 #endif // TASKQUEUE_STATS
185
186 PSPromotionManager::PSPromotionManager() {
187 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
188
189 // We set the old lab's start array.
190 _old_lab.set_start_array(old_gen()->start_array());
191
192 uint queue_size;
193 claimed_stack_depth()->initialize();
194 queue_size = claimed_stack_depth()->max_elems();
195
196 _totally_drain = (ParallelGCThreads == 1) || (GCDrainStackTargetSize == 0);
197 if (_totally_drain) {
198 _target_stack_size = 0;
199 } else {
200 // don't let the target stack size to be more than 1/4 of the entries
201 _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize,
202 (uint) (queue_size / 4));
203 }
204
205 _array_chunk_size = ParGCArrayScanChunk;
206 // let's choose 1.5x the chunk size
207 _min_array_size_for_chunking = 3 * _array_chunk_size / 2;
208
209 _preserved_marks = NULL;
210
211 reset();
212 }
213
214 void PSPromotionManager::reset() {
215 assert(stacks_empty(), "reset of non-empty stack");
216
217 // We need to get an assert in here to make sure the labs are always flushed.
218
219 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
220
221 // Do not prefill the LAB's, save heap wastage!
222 HeapWord* lab_base = young_space()->top();
223 _young_lab.initialize(MemRegion(lab_base, (size_t)0));
224 _young_gen_is_full = false;
225
226 lab_base = old_gen()->object_space()->top();
227 _old_lab.initialize(MemRegion(lab_base, (size_t)0));
228 _old_gen_is_full = false;
229
230 _promotion_failed_info.reset();
231
232 TASKQUEUE_STATS_ONLY(reset_stats());
233 }
234
235 void PSPromotionManager::register_preserved_marks(PreservedMarks* preserved_marks) {
236 assert(_preserved_marks == NULL, "do not set it twice");
237 _preserved_marks = preserved_marks;
238 }
239
240 void PSPromotionManager::restore_preserved_marks() {
241 _preserved_marks_set->restore(PSScavenge::gc_task_manager());
242 }
243
244 void PSPromotionManager::drain_stacks_depth(bool totally_drain) {
245 totally_drain = totally_drain || _totally_drain;
246
247 #ifdef ASSERT
248 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
249 MutableSpace* to_space = heap->young_gen()->to_space();
250 MutableSpace* old_space = heap->old_gen()->object_space();
251 #endif /* ASSERT */
252
253 OopStarTaskQueue* const tq = claimed_stack_depth();
254 do {
255 StarTask p;
256
257 // Drain overflow stack first, so other threads can steal from
258 // claimed stack while we work.
259 while (tq->pop_overflow(p)) {
260 process_popped_location_depth(p);
261 }
262
263 if (totally_drain) {
264 while (tq->pop_local(p)) {
265 process_popped_location_depth(p);
266 }
267 } else {
268 while (tq->size() > _target_stack_size && tq->pop_local(p)) {
269 process_popped_location_depth(p);
270 }
271 }
272 } while (totally_drain && !tq->taskqueue_empty() || !tq->overflow_empty());
273
274 assert(!totally_drain || tq->taskqueue_empty(), "Sanity");
275 assert(totally_drain || tq->size() <= _target_stack_size, "Sanity");
276 assert(tq->overflow_empty(), "Sanity");
277 }
278
279 void PSPromotionManager::flush_labs() {
280 assert(stacks_empty(), "Attempt to flush lab with live stack");
281
282 // If either promotion lab fills up, we can flush the
283 // lab but not refill it, so check first.
284 assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity");
285 if (!_young_lab.is_flushed())
286 _young_lab.flush();
287
288 assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity");
289 if (!_old_lab.is_flushed())
290 _old_lab.flush();
291
292 // Let PSScavenge know if we overflowed
293 if (_young_gen_is_full) {
294 PSScavenge::set_survivor_overflow(true);
295 }
296 }
297
298 template <class T> void PSPromotionManager::process_array_chunk_work(
299 oop obj,
300 int start, int end) {
301 assert(start <= end, "invariant");
302 T* const base = (T*)objArrayOop(obj)->base();
303 T* p = base + start;
304 T* const chunk_end = base + end;
305 while (p < chunk_end) {
306 if (PSScavenge::should_scavenge(p)) {
307 claim_or_forward_depth(p);
308 }
309 ++p;
310 }
311 }
312
313 void PSPromotionManager::process_array_chunk(oop old) {
314 assert(PSChunkLargeArrays, "invariant");
315 assert(old->is_objArray(), "invariant");
316 assert(old->is_forwarded(), "invariant");
317
318 TASKQUEUE_STATS_ONLY(++_array_chunks_processed);
319
320 oop const obj = old->forwardee();
321
322 int start;
323 int const end = arrayOop(old)->length();
324 if (end > (int) _min_array_size_for_chunking) {
325 // we'll chunk more
326 start = end - _array_chunk_size;
327 assert(start > 0, "invariant");
328 arrayOop(old)->set_length(start);
329 push_depth(mask_chunked_array_oop(old));
330 TASKQUEUE_STATS_ONLY(++_masked_pushes);
331 } else {
332 // this is the final chunk for this array
333 start = 0;
334 int const actual_length = arrayOop(obj)->length();
335 arrayOop(old)->set_length(actual_length);
336 }
337
338 if (UseCompressedOops) {
339 process_array_chunk_work<narrowOop>(obj, start, end);
340 } else {
341 process_array_chunk_work<oop>(obj, start, end);
342 }
343 }
344
345 class PushContentsClosure : public ExtendedOopClosure {
346 PSPromotionManager* _pm;
347 public:
348 PushContentsClosure(PSPromotionManager* pm) : _pm(pm) {}
349
350 template <typename T> void do_oop_nv(T* p) {
351 if (PSScavenge::should_scavenge(p)) {
352 _pm->claim_or_forward_depth(p);
353 }
354 }
355
356 virtual void do_oop(oop* p) { do_oop_nv(p); }
357 virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
358
359 // Don't use the oop verification code in the oop_oop_iterate framework.
360 debug_only(virtual bool should_verify_oops() { return false; })
361 };
362
363 void InstanceKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
364 PushContentsClosure cl(pm);
365 oop_oop_iterate_oop_maps_reverse<true>(obj, &cl);
366 }
367
368 void InstanceMirrorKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
369 // Note that we don't have to follow the mirror -> klass pointer, since all
370 // klasses that are dirty will be scavenged when we iterate over the
371 // ClassLoaderData objects.
372
373 InstanceKlass::oop_ps_push_contents(obj, pm);
374
375 PushContentsClosure cl(pm);
376 oop_oop_iterate_statics<true>(obj, &cl);
377 }
378
379 void InstanceClassLoaderKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
380 InstanceKlass::oop_ps_push_contents(obj, pm);
381
382 // This is called by the young collector. It will already have taken care of
383 // all class loader data. So, we don't have to follow the class loader ->
384 // class loader data link.
385 }
386
387 template <class T>
388 static void oop_ps_push_contents_specialized(oop obj, InstanceRefKlass *klass, PSPromotionManager* pm) {
389 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
390 if (PSScavenge::should_scavenge(referent_addr)) {
391 ReferenceProcessor* rp = PSScavenge::reference_processor();
392 if (rp->discover_reference(obj, klass->reference_type())) {
393 // reference already enqueued, referent and next will be traversed later
394 klass->InstanceKlass::oop_ps_push_contents(obj, pm);
395 return;
396 } else {
397 // treat referent as normal oop
398 pm->claim_or_forward_depth(referent_addr);
399 }
400 }
401 // Treat discovered as normal oop, if ref is not "active",
402 // i.e. if next is non-NULL.
403 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
404 T next_oop = oopDesc::load_heap_oop(next_addr);
405 if (!oopDesc::is_null(next_oop)) { // i.e. ref is not "active"
406 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
407 log_develop_trace(gc, ref)(" Process discovered as normal " PTR_FORMAT, p2i(discovered_addr));
408 if (PSScavenge::should_scavenge(discovered_addr)) {
409 pm->claim_or_forward_depth(discovered_addr);
410 }
411 }
412 // Treat next as normal oop; next is a link in the reference queue.
413 if (PSScavenge::should_scavenge(next_addr)) {
414 pm->claim_or_forward_depth(next_addr);
415 }
416 klass->InstanceKlass::oop_ps_push_contents(obj, pm);
417 }
418
419 void InstanceRefKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
420 if (UseCompressedOops) {
421 oop_ps_push_contents_specialized<narrowOop>(obj, this, pm);
422 } else {
423 oop_ps_push_contents_specialized<oop>(obj, this, pm);
424 }
425 }
426
427 void ObjArrayKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
428 assert(obj->is_objArray(), "obj must be obj array");
429 PushContentsClosure cl(pm);
430 oop_oop_iterate_elements<true>(objArrayOop(obj), &cl);
431 }
432
433 void TypeArrayKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
434 assert(obj->is_typeArray(),"must be a type array");
435 ShouldNotReachHere();
436 }
437
438 oop PSPromotionManager::oop_promotion_failed(oop obj, markOop obj_mark) {
439 assert(_old_gen_is_full || PromotionFailureALot, "Sanity");
440
441 // Attempt to CAS in the header.
442 // This tests if the header is still the same as when
443 // this started. If it is the same (i.e., no forwarding
444 // pointer has been installed), then this thread owns
445 // it.
446 if (obj->cas_forward_to(obj, obj_mark)) {
447 // We won any races, we "own" this object.
448 assert(obj == obj->forwardee(), "Sanity");
449
450 _promotion_failed_info.register_copy_failure(obj->size());
451
452 push_contents(obj);
453
454 _preserved_marks->push_if_necessary(obj, obj_mark);
455 } else {
456 // We lost, someone else "owns" this object
457 guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed.");
458
459 // No unallocation to worry about.
460 obj = obj->forwardee();
461 }
462
463 log_develop_trace(gc, scavenge)("{promotion-failure %s " PTR_FORMAT " (%d)}", obj->klass()->internal_name(), p2i(obj), obj->size());
464
465 return obj;
466 }