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/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 "oops/instanceKlass.inline.hpp"
39 #include "oops/instanceMirrorKlass.inline.hpp"
40 #include "oops/objArrayKlass.inline.hpp"
41 #include "oops/oop.inline.hpp"
42
43 PaddedEnd<PSPromotionManager>* PSPromotionManager::_manager_array = NULL;
44 OopStarTaskQueueSet* PSPromotionManager::_stack_array_depth = NULL;
45 PreservedMarksSet* PSPromotionManager::_preserved_marks_set = NULL;
46 PSOldGen* PSPromotionManager::_old_gen = NULL;
47 MutableSpace* PSPromotionManager::_young_space = NULL;
48
49 void PSPromotionManager::initialize() {
50 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
51
52 _old_gen = heap->old_gen();
53 _young_space = heap->young_gen()->to_space();
54
55 const uint promotion_manager_num = ParallelGCThreads + 1;
56
57 // To prevent false sharing, we pad the PSPromotionManagers
58 // and make sure that the first instance starts at a cache line.
59 assert(_manager_array == NULL, "Attempt to initialize twice");
60 _manager_array = PaddedArray<PSPromotionManager, mtGC>::create_unfreeable(promotion_manager_num);
61 guarantee(_manager_array != NULL, "Could not initialize promotion manager");
62
63 _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads);
64 guarantee(_stack_array_depth != NULL, "Could not initialize promotion manager");
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 guarantee(_preserved_marks_set != NULL, "Could not initialize preserved marks set");
76 _preserved_marks_set->init(promotion_manager_num);
77 for (uint i = 0; i < promotion_manager_num; i += 1) {
78 _manager_array[i].register_preserved_marks(_preserved_marks_set->get(i));
79 }
80 }
81
82 // Helper functions to get around the circular dependency between
83 // psScavenge.inline.hpp and psPromotionManager.inline.hpp.
84 bool PSPromotionManager::should_scavenge(oop* p, bool check_to_space) {
85 return PSScavenge::should_scavenge(p, check_to_space);
86 }
87 bool PSPromotionManager::should_scavenge(narrowOop* p, bool check_to_space) {
88 return PSScavenge::should_scavenge(p, check_to_space);
89 }
90
91 PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(uint index) {
92 assert(index < ParallelGCThreads, "index out of range");
93 assert(_manager_array != NULL, "Sanity");
94 return &_manager_array[index];
95 }
96
97 PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() {
98 assert(_manager_array != NULL, "Sanity");
99 return &_manager_array[ParallelGCThreads];
100 }
101
102 void PSPromotionManager::pre_scavenge() {
103 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
104
105 _preserved_marks_set->assert_empty();
106 _young_space = heap->young_gen()->to_space();
107
108 for(uint i=0; i<ParallelGCThreads+1; i++) {
109 manager_array(i)->reset();
110 }
111 }
112
113 bool PSPromotionManager::post_scavenge(YoungGCTracer& gc_tracer) {
114 bool promotion_failure_occurred = false;
115
116 TASKQUEUE_STATS_ONLY(print_taskqueue_stats());
117 for (uint i = 0; i < ParallelGCThreads + 1; i++) {
118 PSPromotionManager* manager = manager_array(i);
119 assert(manager->claimed_stack_depth()->is_empty(), "should be empty");
120 if (manager->_promotion_failed_info.has_failed()) {
121 gc_tracer.report_promotion_failed(manager->_promotion_failed_info);
122 promotion_failure_occurred = true;
123 }
124 manager->flush_labs();
125 }
126 if (!promotion_failure_occurred) {
127 // If there was no promotion failure, the preserved mark stacks
128 // should be empty.
129 _preserved_marks_set->assert_empty();
130 }
131 return promotion_failure_occurred;
132 }
133
134 #if TASKQUEUE_STATS
135 void
136 PSPromotionManager::print_local_stats(outputStream* const out, uint i) const {
137 #define FMT " " SIZE_FORMAT_W(10)
138 out->print_cr("%3u" FMT FMT FMT FMT, i, _masked_pushes, _masked_steals,
139 _arrays_chunked, _array_chunks_processed);
140 #undef FMT
141 }
142
143 static const char* const pm_stats_hdr[] = {
144 " --------masked------- arrays array",
145 "thr push steal chunked chunks",
146 "--- ---------- ---------- ---------- ----------"
147 };
148
149 void
150 PSPromotionManager::print_taskqueue_stats() {
151 if (!log_develop_is_enabled(Trace, gc, task, stats)) {
152 return;
153 }
154 LogHandle(gc, task, stats) log;
155 ResourceMark rm;
156 outputStream* out = log.trace_stream();
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::drain_stacks_depth(bool totally_drain) {
240 totally_drain = totally_drain || _totally_drain;
241
242 #ifdef ASSERT
243 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
244 MutableSpace* to_space = heap->young_gen()->to_space();
245 MutableSpace* old_space = heap->old_gen()->object_space();
246 #endif /* ASSERT */
247
248 OopStarTaskQueue* const tq = claimed_stack_depth();
249 do {
250 StarTask p;
251
252 // Drain overflow stack first, so other threads can steal from
253 // claimed stack while we work.
254 while (tq->pop_overflow(p)) {
255 process_popped_location_depth(p);
256 }
257
258 if (totally_drain) {
259 while (tq->pop_local(p)) {
260 process_popped_location_depth(p);
261 }
262 } else {
263 while (tq->size() > _target_stack_size && tq->pop_local(p)) {
264 process_popped_location_depth(p);
265 }
266 }
267 } while (totally_drain && !tq->taskqueue_empty() || !tq->overflow_empty());
268
269 assert(!totally_drain || tq->taskqueue_empty(), "Sanity");
270 assert(totally_drain || tq->size() <= _target_stack_size, "Sanity");
271 assert(tq->overflow_empty(), "Sanity");
272 }
273
274 void PSPromotionManager::flush_labs() {
275 assert(stacks_empty(), "Attempt to flush lab with live stack");
276
277 // If either promotion lab fills up, we can flush the
278 // lab but not refill it, so check first.
279 assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity");
280 if (!_young_lab.is_flushed())
281 _young_lab.flush();
282
283 assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity");
284 if (!_old_lab.is_flushed())
285 _old_lab.flush();
286
287 // Let PSScavenge know if we overflowed
288 if (_young_gen_is_full) {
289 PSScavenge::set_survivor_overflow(true);
290 }
291 }
292
293 template <class T> void PSPromotionManager::process_array_chunk_work(
294 oop obj,
295 int start, int end) {
296 assert(start <= end, "invariant");
297 T* const base = (T*)objArrayOop(obj)->base();
298 T* p = base + start;
299 T* const chunk_end = base + end;
300 while (p < chunk_end) {
301 if (PSScavenge::should_scavenge(p)) {
302 claim_or_forward_depth(p);
303 }
304 ++p;
305 }
306 }
307
308 void PSPromotionManager::process_array_chunk(oop old) {
309 assert(PSChunkLargeArrays, "invariant");
310 assert(old->is_objArray(), "invariant");
311 assert(old->is_forwarded(), "invariant");
312
313 TASKQUEUE_STATS_ONLY(++_array_chunks_processed);
314
315 oop const obj = old->forwardee();
316
317 int start;
318 int const end = arrayOop(old)->length();
319 if (end > (int) _min_array_size_for_chunking) {
320 // we'll chunk more
321 start = end - _array_chunk_size;
322 assert(start > 0, "invariant");
323 arrayOop(old)->set_length(start);
324 push_depth(mask_chunked_array_oop(old));
325 TASKQUEUE_STATS_ONLY(++_masked_pushes);
326 } else {
327 // this is the final chunk for this array
328 start = 0;
329 int const actual_length = arrayOop(obj)->length();
330 arrayOop(old)->set_length(actual_length);
331 }
332
333 if (UseCompressedOops) {
334 process_array_chunk_work<narrowOop>(obj, start, end);
335 } else {
336 process_array_chunk_work<oop>(obj, start, end);
337 }
338 }
339
340 class PushContentsClosure : public ExtendedOopClosure {
341 PSPromotionManager* _pm;
342 public:
343 PushContentsClosure(PSPromotionManager* pm) : _pm(pm) {}
344
345 template <typename T> void do_oop_nv(T* p) {
346 if (PSScavenge::should_scavenge(p)) {
347 _pm->claim_or_forward_depth(p);
348 }
349 }
350
351 virtual void do_oop(oop* p) { do_oop_nv(p); }
352 virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
353
354 // Don't use the oop verification code in the oop_oop_iterate framework.
355 debug_only(virtual bool should_verify_oops() { return false; })
356 };
357
358 void InstanceKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
359 PushContentsClosure cl(pm);
360 oop_oop_iterate_oop_maps_reverse<true>(obj, &cl);
361 }
362
363 void InstanceMirrorKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
364 // Note that we don't have to follow the mirror -> klass pointer, since all
365 // klasses that are dirty will be scavenged when we iterate over the
366 // ClassLoaderData objects.
367
368 InstanceKlass::oop_ps_push_contents(obj, pm);
369
370 PushContentsClosure cl(pm);
371 oop_oop_iterate_statics<true>(obj, &cl);
372 }
373
374 void InstanceClassLoaderKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
375 InstanceKlass::oop_ps_push_contents(obj, pm);
376
377 // This is called by the young collector. It will already have taken care of
378 // all class loader data. So, we don't have to follow the class loader ->
379 // class loader data link.
380 }
381
382 template <class T>
383 static void oop_ps_push_contents_specialized(oop obj, InstanceRefKlass *klass, PSPromotionManager* pm) {
384 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
385 if (PSScavenge::should_scavenge(referent_addr)) {
386 ReferenceProcessor* rp = PSScavenge::reference_processor();
387 if (rp->discover_reference(obj, klass->reference_type())) {
388 // reference already enqueued, referent and next will be traversed later
389 klass->InstanceKlass::oop_ps_push_contents(obj, pm);
390 return;
391 } else {
392 // treat referent as normal oop
393 pm->claim_or_forward_depth(referent_addr);
394 }
395 }
396 // Treat discovered as normal oop, if ref is not "active",
397 // i.e. if next is non-NULL.
398 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
399 T next_oop = oopDesc::load_heap_oop(next_addr);
400 if (!oopDesc::is_null(next_oop)) { // i.e. ref is not "active"
401 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
402 log_develop_trace(gc, ref)(" Process discovered as normal " PTR_FORMAT, p2i(discovered_addr));
403 if (PSScavenge::should_scavenge(discovered_addr)) {
404 pm->claim_or_forward_depth(discovered_addr);
405 }
406 }
407 // Treat next as normal oop; next is a link in the reference queue.
408 if (PSScavenge::should_scavenge(next_addr)) {
409 pm->claim_or_forward_depth(next_addr);
410 }
411 klass->InstanceKlass::oop_ps_push_contents(obj, pm);
412 }
413
414 void InstanceRefKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
415 if (UseCompressedOops) {
416 oop_ps_push_contents_specialized<narrowOop>(obj, this, pm);
417 } else {
418 oop_ps_push_contents_specialized<oop>(obj, this, pm);
419 }
420 }
421
422 void ObjArrayKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
423 assert(obj->is_objArray(), "obj must be obj array");
424 PushContentsClosure cl(pm);
425 oop_oop_iterate_elements<true>(objArrayOop(obj), &cl);
426 }
427
428 void TypeArrayKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
429 assert(obj->is_typeArray(),"must be a type array");
430 ShouldNotReachHere();
431 }
432
433 oop PSPromotionManager::oop_promotion_failed(oop obj, markOop obj_mark) {
434 assert(_old_gen_is_full || PromotionFailureALot, "Sanity");
435
436 // Attempt to CAS in the header.
437 // This tests if the header is still the same as when
438 // this started. If it is the same (i.e., no forwarding
439 // pointer has been installed), then this thread owns
440 // it.
441 if (obj->cas_forward_to(obj, obj_mark)) {
442 // We won any races, we "own" this object.
443 assert(obj == obj->forwardee(), "Sanity");
444
445 _promotion_failed_info.register_copy_failure(obj->size());
446
447 push_contents(obj);
448
449 _preserved_marks->push_if_necessary(obj, obj_mark);
450 } else {
451 // We lost, someone else "owns" this object
452 guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed.");
453
454 // No unallocation to worry about.
455 obj = obj->forwardee();
456 }
457
458 log_develop_trace(gc, scavenge)("{promotion-failure %s " PTR_FORMAT " (%d)}", obj->klass()->internal_name(), p2i(obj), obj->size());
459
460 return obj;
461 }