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