1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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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 *
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24
25 #ifndef SHARE_GC_PARALLEL_PSPROMOTIONMANAGER_INLINE_HPP
26 #define SHARE_GC_PARALLEL_PSPROMOTIONMANAGER_INLINE_HPP
27
28 #include "gc/parallel/psPromotionManager.hpp"
29
30 #include "gc/parallel/parallelScavengeHeap.hpp"
31 #include "gc/parallel/parMarkBitMap.inline.hpp"
32 #include "gc/parallel/psOldGen.hpp"
33 #include "gc/parallel/psPromotionLAB.inline.hpp"
34 #include "gc/parallel/psScavenge.inline.hpp"
35 #include "gc/parallel/psStringDedup.hpp"
36 #include "gc/shared/continuationGCSupport.inline.hpp"
37 #include "gc/shared/taskqueue.inline.hpp"
38 #include "gc/shared/tlab_globals.hpp"
39 #include "logging/log.hpp"
40 #include "memory/iterator.inline.hpp"
41 #include "oops/access.inline.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "runtime/orderAccess.hpp"
44 #include "runtime/prefetch.inline.hpp"
45 #include "utilities/copy.hpp"
46
47 inline PSPromotionManager* PSPromotionManager::manager_array(uint index) {
48 assert(_manager_array != nullptr, "access of null manager_array");
49 assert(index < ParallelGCThreads, "out of range manager_array access");
50 return &_manager_array[index];
51 }
52
53 inline void PSPromotionManager::push_depth(ScannerTask task) {
54 claimed_stack_depth()->push(task);
55 }
56
57 template <class T>
58 inline void PSPromotionManager::claim_or_forward_depth(T* p) {
59 assert(should_scavenge(p, true), "revisiting object?");
60 assert(ParallelScavengeHeap::heap()->is_in(p), "pointer outside heap");
61 oop obj = RawAccess<IS_NOT_NULL>::oop_load(p);
62 Prefetch::write(obj->mark_addr(), 0);
63 push_depth(ScannerTask(p));
64 }
65
66 inline void PSPromotionManager::promotion_trace_event(oop new_obj, oop old_obj,
67 size_t obj_size,
68 uint age, bool tenured,
69 const PSPromotionLAB* lab) {
70 // Skip if memory allocation failed
71 if (new_obj != nullptr) {
72 const ParallelScavengeTracer* gc_tracer = PSScavenge::gc_tracer();
73
74 if (lab != nullptr) {
75 // Promotion of object through newly allocated PLAB
76 if (gc_tracer->should_report_promotion_in_new_plab_event()) {
77 size_t obj_bytes = obj_size * HeapWordSize;
78 size_t lab_size = lab->capacity();
79 gc_tracer->report_promotion_in_new_plab_event(old_obj->klass(), obj_bytes,
80 age, tenured, lab_size);
81 }
82 } else {
83 // Promotion of object directly to heap
84 if (gc_tracer->should_report_promotion_outside_plab_event()) {
85 size_t obj_bytes = obj_size * HeapWordSize;
86 gc_tracer->report_promotion_outside_plab_event(old_obj->klass(), obj_bytes,
87 age, tenured);
88 }
89 }
90 }
91 }
92
93 class PSPushContentsClosure: public BasicOopIterateClosure {
94 PSPromotionManager* _pm;
95 public:
96 PSPushContentsClosure(PSPromotionManager* pm) : BasicOopIterateClosure(PSScavenge::reference_processor()), _pm(pm) {}
97
98 template <typename T> void do_oop_nv(T* p) {
99 if (PSScavenge::should_scavenge(p)) {
100 _pm->claim_or_forward_depth(p);
101 }
102 }
103
104 virtual void do_oop(oop* p) { do_oop_nv(p); }
105 virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
106 };
107
108 //
109 // This closure specialization will override the one that is defined in
110 // instanceRefKlass.inline.cpp. It swaps the order of oop_oop_iterate and
111 // oop_oop_iterate_ref_processing. Unfortunately G1 and Parallel behaves
112 // significantly better (especially in the Derby benchmark) using opposite
113 // order of these function calls.
114 //
115 template <>
116 inline void InstanceRefKlass::oop_oop_iterate_reverse<oop, PSPushContentsClosure>(oop obj, PSPushContentsClosure* closure) {
117 oop_oop_iterate_ref_processing<oop>(obj, closure);
118 InstanceKlass::oop_oop_iterate_reverse<oop>(obj, closure);
119 }
120
121 template <>
122 inline void InstanceRefKlass::oop_oop_iterate_reverse<narrowOop, PSPushContentsClosure>(oop obj, PSPushContentsClosure* closure) {
123 oop_oop_iterate_ref_processing<narrowOop>(obj, closure);
124 InstanceKlass::oop_oop_iterate_reverse<narrowOop>(obj, closure);
125 }
126
127 inline void PSPromotionManager::push_contents(oop obj) {
128 if (!obj->klass()->is_typeArray_klass()) {
129 PSPushContentsClosure pcc(this);
130 obj->oop_iterate_backwards(&pcc);
131 }
132 }
133
134 template<bool promote_immediately>
135 inline oop PSPromotionManager::copy_to_survivor_space(oop o) {
136 assert(should_scavenge(&o), "Sanity");
137
138 // NOTE! We must be very careful with any methods that access the mark
139 // in o. There may be multiple threads racing on it, and it may be forwarded
140 // at any time.
141 markWord m = o->mark();
142 if (!m.is_marked()) {
143 return copy_unmarked_to_survivor_space<promote_immediately>(o, m);
144 } else {
145 // Ensure any loads from the forwardee follow all changes that precede
146 // the release-cmpxchg that performed the forwarding, possibly in some
147 // other thread.
148 OrderAccess::acquire();
149 // Return the already installed forwardee.
150 return cast_to_oop(m.decode_pointer());
151 }
152 }
153
154 //
155 // This method is pretty bulky. It would be nice to split it up
156 // into smaller submethods, but we need to be careful not to hurt
157 // performance.
158 //
159 template<bool promote_immediately>
160 inline oop PSPromotionManager::copy_unmarked_to_survivor_space(oop o,
161 markWord test_mark) {
162 assert(should_scavenge(&o), "Sanity");
163
164 oop new_obj = nullptr;
165 bool new_obj_is_tenured = false;
166 size_t new_obj_size = o->size();
167
168 // Find the objects age, MT safe.
169 uint age = (test_mark.has_displaced_mark_helper() /* o->has_displaced_mark() */) ?
170 test_mark.displaced_mark_helper().age() : test_mark.age();
171
172 if (!promote_immediately) {
173 // Try allocating obj in to-space (unless too old)
174 if (age < PSScavenge::tenuring_threshold()) {
175 new_obj = cast_to_oop(_young_lab.allocate(new_obj_size));
176 if (new_obj == nullptr && !_young_gen_is_full) {
177 // Do we allocate directly, or flush and refill?
178 if (new_obj_size > (YoungPLABSize / 2)) {
179 // Allocate this object directly
180 new_obj = cast_to_oop(young_space()->cas_allocate(new_obj_size));
181 promotion_trace_event(new_obj, o, new_obj_size, age, false, nullptr);
182 } else {
183 // Flush and fill
184 _young_lab.flush();
185
186 HeapWord* lab_base = young_space()->cas_allocate(YoungPLABSize);
187 if (lab_base != nullptr) {
188 _young_lab.initialize(MemRegion(lab_base, YoungPLABSize));
189 // Try the young lab allocation again.
190 new_obj = cast_to_oop(_young_lab.allocate(new_obj_size));
191 promotion_trace_event(new_obj, o, new_obj_size, age, false, &_young_lab);
192 } else {
193 _young_gen_is_full = true;
194 }
195 }
196 }
197 }
198 }
199
200 // Otherwise try allocating obj tenured
201 if (new_obj == nullptr) {
202 #ifndef PRODUCT
203 if (ParallelScavengeHeap::heap()->promotion_should_fail()) {
204 return oop_promotion_failed(o, test_mark);
205 }
206 #endif // #ifndef PRODUCT
207
208 new_obj = cast_to_oop(_old_lab.allocate(new_obj_size));
209 new_obj_is_tenured = true;
210
211 if (new_obj == nullptr) {
212 if (!_old_gen_is_full) {
213 // Do we allocate directly, or flush and refill?
214 if (new_obj_size > (OldPLABSize / 2)) {
215 // Allocate this object directly
216 new_obj = cast_to_oop(old_gen()->allocate(new_obj_size));
217 promotion_trace_event(new_obj, o, new_obj_size, age, true, nullptr);
218 } else {
219 // Flush and fill
220 _old_lab.flush();
221
222 HeapWord* lab_base = old_gen()->allocate(OldPLABSize);
223 if(lab_base != nullptr) {
224 _old_lab.initialize(MemRegion(lab_base, OldPLABSize));
225 // Try the old lab allocation again.
226 new_obj = cast_to_oop(_old_lab.allocate(new_obj_size));
227 promotion_trace_event(new_obj, o, new_obj_size, age, true, &_old_lab);
228 }
229 }
230 }
231
232 // This is the promotion failed test, and code handling.
233 // The code belongs here for two reasons. It is slightly
234 // different than the code below, and cannot share the
235 // CAS testing code. Keeping the code here also minimizes
236 // the impact on the common case fast path code.
237
238 if (new_obj == nullptr) {
239 _old_gen_is_full = true;
240 return oop_promotion_failed(o, test_mark);
241 }
242 }
243 }
244
245 assert(new_obj != nullptr, "allocation should have succeeded");
246
247 // Copy obj
248 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(o), cast_from_oop<HeapWord*>(new_obj), new_obj_size);
249
250 // Parallel GC claims with a release - so other threads might access this object
251 // after claiming and they should see the "completed" object.
252 ContinuationGCSupport::transform_stack_chunk(new_obj);
253
254 // Now we have to CAS in the header.
255 // Make copy visible to threads reading the forwardee.
256 oop forwardee = o->forward_to_atomic(new_obj, test_mark, memory_order_release);
257 if (forwardee == nullptr) { // forwardee is null when forwarding is successful
258 // We won any races, we "own" this object.
259 assert(new_obj == o->forwardee(), "Sanity");
260
261 // Increment age if obj still in new generation. Now that
262 // we're dealing with a markWord that cannot change, it is
263 // okay to use the non mt safe oop methods.
264 if (!new_obj_is_tenured) {
265 new_obj->incr_age();
266 assert(young_space()->contains(new_obj), "Attempt to push non-promoted obj");
267 }
268
269 // Do the size comparison first with new_obj_size, which we
270 // already have. Hopefully, only a few objects are larger than
271 // _min_array_size_for_chunking, and most of them will be arrays.
272 // So, the is->objArray() test would be very infrequent.
273 if (new_obj_size > _min_array_size_for_chunking &&
274 new_obj->is_objArray() &&
275 PSChunkLargeArrays) {
276 // we'll chunk it
277 push_depth(ScannerTask(PartialArrayScanTask(o)));
278 TASKQUEUE_STATS_ONLY(++_arrays_chunked; ++_array_chunk_pushes);
279 } else {
280 // we'll just push its contents
281 push_contents(new_obj);
282
283 if (StringDedup::is_enabled() &&
284 java_lang_String::is_instance(new_obj) &&
285 psStringDedup::is_candidate_from_evacuation(new_obj, new_obj_is_tenured)) {
286 _string_dedup_requests.add(o);
287 }
288 }
289 return new_obj;
290 } else {
291 // We lost, someone else "owns" this object.
292 // Ensure loads from the forwardee follow all changes that preceded the
293 // release-cmpxchg that performed the forwarding in another thread.
294 OrderAccess::acquire();
295
296 assert(o->is_forwarded(), "Object must be forwarded if the cas failed.");
297 assert(o->forwardee() == forwardee, "invariant");
298
299 if (new_obj_is_tenured) {
300 _old_lab.unallocate_object(cast_from_oop<HeapWord*>(new_obj), new_obj_size);
301 } else {
302 _young_lab.unallocate_object(cast_from_oop<HeapWord*>(new_obj), new_obj_size);
303 }
304 return forwardee;
305 }
306 }
307
308 // Attempt to "claim" oop at p via CAS, push the new obj if successful
309 template <bool promote_immediately, class T>
310 inline void PSPromotionManager::copy_and_push_safe_barrier(T* p) {
311 assert(ParallelScavengeHeap::heap()->is_in_reserved(p), "precondition");
312 assert(should_scavenge(p, true), "revisiting object?");
313
314 oop o = RawAccess<IS_NOT_NULL>::oop_load(p);
315 oop new_obj = copy_to_survivor_space<promote_immediately>(o);
316 RawAccess<IS_NOT_NULL>::oop_store(p, new_obj);
317
318 if (!PSScavenge::is_obj_in_young((HeapWord*)p) &&
319 PSScavenge::is_obj_in_young(new_obj)) {
320 PSScavenge::card_table()->inline_write_ref_field_gc(p);
321 }
322 }
323
324 inline void PSPromotionManager::process_popped_location_depth(ScannerTask task) {
325 if (task.is_partial_array_task()) {
326 assert(PSChunkLargeArrays, "invariant");
327 process_array_chunk(task.to_partial_array_task());
328 } else {
329 if (task.is_narrow_oop_ptr()) {
330 assert(UseCompressedOops, "Error");
331 copy_and_push_safe_barrier</*promote_immediately=*/false>(task.to_narrow_oop_ptr());
332 } else {
333 copy_and_push_safe_barrier</*promote_immediately=*/false>(task.to_oop_ptr());
334 }
335 }
336 }
337
338 inline bool PSPromotionManager::steal_depth(int queue_num, ScannerTask& t) {
339 return stack_array_depth()->steal(queue_num, t);
340 }
341
342 #if TASKQUEUE_STATS
343 void PSPromotionManager::record_steal(ScannerTask task) {
344 if (task.is_partial_array_task()) {
345 ++_array_chunk_steals;
346 }
347 }
348 #endif // TASKQUEUE_STATS
349
350 #endif // SHARE_GC_PARALLEL_PSPROMOTIONMANAGER_INLINE_HPP