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