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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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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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(ParallelScavengeHeap::heap()->is_in(p), "pointer outside heap");
60 T heap_oop = RawAccess<>::oop_load(p);
61 if (PSScavenge::is_obj_in_young(heap_oop)) {
62 oop obj = CompressedOops::decode_not_null(heap_oop);
63 assert(!PSScavenge::is_obj_in_to_space(obj), "revisiting object?");
64 Prefetch::write(obj->mark_addr(), 0);
65 push_depth(ScannerTask(p));
66 }
67 }
68
69 inline void PSPromotionManager::promotion_trace_event(oop new_obj, oop old_obj,
70 size_t obj_size,
71 uint age, bool tenured,
72 const PSPromotionLAB* lab) {
73 // Skip if memory allocation failed
74 if (new_obj != nullptr) {
75 const ParallelScavengeTracer* gc_tracer = PSScavenge::gc_tracer();
76
77 if (lab != nullptr) {
78 // Promotion of object through newly allocated PLAB
79 if (gc_tracer->should_report_promotion_in_new_plab_event()) {
80 size_t obj_bytes = obj_size * HeapWordSize;
81 size_t lab_size = lab->capacity();
82 gc_tracer->report_promotion_in_new_plab_event(old_obj->klass(), obj_bytes,
83 age, tenured, lab_size);
84 }
85 } else {
86 // Promotion of object directly to heap
87 if (gc_tracer->should_report_promotion_outside_plab_event()) {
88 size_t obj_bytes = obj_size * HeapWordSize;
89 gc_tracer->report_promotion_outside_plab_event(old_obj->klass(), obj_bytes,
90 age, tenured);
91 }
92 }
93 }
94 }
95
96 class PSPushContentsClosure: public BasicOopIterateClosure {
97 PSPromotionManager* _pm;
98 public:
99 PSPushContentsClosure(PSPromotionManager* pm) : BasicOopIterateClosure(PSScavenge::reference_processor()), _pm(pm) {}
100
101 template <typename T> void do_oop_work(T* p) {
102 _pm->claim_or_forward_depth(p);
103 }
104
105 virtual void do_oop(oop* p) { do_oop_work(p); }
106 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
107 };
108
109 //
110 // This closure specialization will override the one that is defined in
111 // instanceRefKlass.inline.cpp. It swaps the order of oop_oop_iterate and
112 // oop_oop_iterate_ref_processing. Unfortunately G1 and Parallel behaves
113 // significantly better (especially in the Derby benchmark) using opposite
114 // order of these function calls.
115 //
116 template <>
117 inline void InstanceRefKlass::oop_oop_iterate_reverse<oop, PSPushContentsClosure>(oop obj, PSPushContentsClosure* closure) {
118 oop_oop_iterate_ref_processing<oop>(obj, closure);
119 InstanceKlass::oop_oop_iterate_reverse<oop>(obj, closure);
120 }
121
122 template <>
123 inline void InstanceRefKlass::oop_oop_iterate_reverse<narrowOop, PSPushContentsClosure>(oop obj, PSPushContentsClosure* closure) {
124 oop_oop_iterate_ref_processing<narrowOop>(obj, closure);
125 InstanceKlass::oop_oop_iterate_reverse<narrowOop>(obj, closure);
126 }
127
128 inline void PSPromotionManager::push_contents(oop obj) {
129 if (!obj->klass()->is_typeArray_klass()) {
130 PSPushContentsClosure pcc(this);
131 obj->oop_iterate_backwards(&pcc);
132 }
133 }
134
135 inline void PSPromotionManager::push_contents_bounded(oop obj, HeapWord* left, HeapWord* right) {
136 PSPushContentsClosure pcc(this);
137 obj->oop_iterate(&pcc, MemRegion(left, right));
138 }
139
140 template<bool promote_immediately>
141 inline oop PSPromotionManager::copy_to_survivor_space(oop o) {
142 assert(should_scavenge(&o), "Sanity");
143
144 // NOTE! We must be very careful with any methods that access the mark
145 // in o. There may be multiple threads racing on it, and it may be forwarded
146 // at any time.
147 markWord m = o->mark();
148 if (!m.is_marked()) {
149 return copy_unmarked_to_survivor_space<promote_immediately>(o, m);
150 } else {
151 // Ensure any loads from the forwardee follow all changes that precede
152 // the release-cmpxchg that performed the forwarding, possibly in some
153 // other thread.
154 OrderAccess::acquire();
155 // Return the already installed forwardee.
156 return cast_to_oop(m.decode_pointer());
157 }
158 }
159
160 //
161 // This method is pretty bulky. It would be nice to split it up
162 // into smaller submethods, but we need to be careful not to hurt
163 // performance.
164 //
165 template<bool promote_immediately>
166 inline oop PSPromotionManager::copy_unmarked_to_survivor_space(oop o,
167 markWord test_mark) {
168 assert(should_scavenge(&o), "Sanity");
169
170 oop new_obj = nullptr;
171 bool new_obj_is_tenured = false;
172 size_t new_obj_size = o->size();
173
174 // Find the objects age, MT safe.
175 uint age = (test_mark.has_displaced_mark_helper() /* o->has_displaced_mark() */) ?
176 test_mark.displaced_mark_helper().age() : test_mark.age();
177
178 if (!promote_immediately) {
179 // Try allocating obj in to-space (unless too old)
180 if (age < PSScavenge::tenuring_threshold()) {
181 new_obj = cast_to_oop(_young_lab.allocate(new_obj_size));
182 if (new_obj == nullptr && !_young_gen_is_full) {
183 // Do we allocate directly, or flush and refill?
184 if (new_obj_size > (YoungPLABSize / 2)) {
185 // Allocate this object directly
186 new_obj = cast_to_oop(young_space()->cas_allocate(new_obj_size));
187 promotion_trace_event(new_obj, o, new_obj_size, age, false, nullptr);
188 } else {
189 // Flush and fill
190 _young_lab.flush();
191
192 HeapWord* lab_base = young_space()->cas_allocate(YoungPLABSize);
193 if (lab_base != nullptr) {
194 _young_lab.initialize(MemRegion(lab_base, YoungPLABSize));
195 // Try the young lab allocation again.
196 new_obj = cast_to_oop(_young_lab.allocate(new_obj_size));
197 promotion_trace_event(new_obj, o, new_obj_size, age, false, &_young_lab);
198 } else {
199 _young_gen_is_full = true;
200 }
201 }
202 }
203 }
204 }
205
206 // Otherwise try allocating obj tenured
207 if (new_obj == nullptr) {
208 #ifndef PRODUCT
209 if (ParallelScavengeHeap::heap()->promotion_should_fail()) {
210 return oop_promotion_failed(o, test_mark);
211 }
212 #endif // #ifndef PRODUCT
213
214 new_obj = cast_to_oop(_old_lab.allocate(new_obj_size));
215 new_obj_is_tenured = true;
216
217 if (new_obj == nullptr) {
218 if (!_old_gen_is_full) {
219 // Do we allocate directly, or flush and refill?
220 if (new_obj_size > (OldPLABSize / 2)) {
221 // Allocate this object directly
222 new_obj = cast_to_oop(old_gen()->allocate(new_obj_size));
223 promotion_trace_event(new_obj, o, new_obj_size, age, true, nullptr);
224 } else {
225 // Flush and fill
226 _old_lab.flush();
227
228 HeapWord* lab_base = old_gen()->allocate(OldPLABSize);
229 if(lab_base != nullptr) {
230 _old_lab.initialize(MemRegion(lab_base, OldPLABSize));
231 // Try the old lab allocation again.
232 new_obj = cast_to_oop(_old_lab.allocate(new_obj_size));
233 promotion_trace_event(new_obj, o, new_obj_size, age, true, &_old_lab);
234 }
235 }
236 }
237
238 // This is the promotion failed test, and code handling.
239 // The code belongs here for two reasons. It is slightly
240 // different than the code below, and cannot share the
241 // CAS testing code. Keeping the code here also minimizes
242 // the impact on the common case fast path code.
243
244 if (new_obj == nullptr) {
245 _old_gen_is_full = true;
246 return oop_promotion_failed(o, test_mark);
247 }
248 }
249 }
250
251 assert(new_obj != nullptr, "allocation should have succeeded");
252
253 // Copy obj
254 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(o), cast_from_oop<HeapWord*>(new_obj), new_obj_size);
255
256 // Parallel GC claims with a release - so other threads might access this object
257 // after claiming and they should see the "completed" object.
258 ContinuationGCSupport::transform_stack_chunk(new_obj);
259
260 // Now we have to CAS in the header.
261 // Make copy visible to threads reading the forwardee.
262 oop forwardee = o->forward_to_atomic(new_obj, test_mark, memory_order_release);
263 if (forwardee == nullptr) { // forwardee is null when forwarding is successful
264 // We won any races, we "own" this object.
265 assert(new_obj == o->forwardee(), "Sanity");
266
267 // Increment age if obj still in new generation. Now that
268 // we're dealing with a markWord that cannot change, it is
269 // okay to use the non mt safe oop methods.
270 if (!new_obj_is_tenured) {
271 new_obj->incr_age();
272 assert(young_space()->contains(new_obj), "Attempt to push non-promoted obj");
273 }
274
275 // Do the size comparison first with new_obj_size, which we
276 // already have. Hopefully, only a few objects are larger than
277 // _min_array_size_for_chunking, and most of them will be arrays.
278 // So, the is->objArray() test would be very infrequent.
279 if (new_obj_size > _min_array_size_for_chunking &&
280 new_obj->is_objArray() &&
281 PSChunkLargeArrays) {
282 // we'll chunk it
283 push_depth(ScannerTask(PartialArrayScanTask(o)));
284 TASKQUEUE_STATS_ONLY(++_arrays_chunked; ++_array_chunk_pushes);
285 } else {
286 // we'll just push its contents
287 push_contents(new_obj);
288
289 if (StringDedup::is_enabled() &&
290 java_lang_String::is_instance(new_obj) &&
291 psStringDedup::is_candidate_from_evacuation(new_obj, new_obj_is_tenured)) {
292 _string_dedup_requests.add(o);
293 }
294 }
295 return new_obj;
296 } else {
297 // We lost, someone else "owns" this object.
298 // Ensure loads from the forwardee follow all changes that preceded the
299 // release-cmpxchg that performed the forwarding in another thread.
300 OrderAccess::acquire();
301
302 assert(o->is_forwarded(), "Object must be forwarded if the cas failed.");
303 assert(o->forwardee() == forwardee, "invariant");
304
305 if (new_obj_is_tenured) {
306 _old_lab.unallocate_object(cast_from_oop<HeapWord*>(new_obj), new_obj_size);
307 } else {
308 _young_lab.unallocate_object(cast_from_oop<HeapWord*>(new_obj), new_obj_size);
309 }
310 return forwardee;
311 }
312 }
313
314 // Attempt to "claim" oop at p via CAS, push the new obj if successful
315 template <bool promote_immediately, class T>
316 inline void PSPromotionManager::copy_and_push_safe_barrier(T* p) {
317 assert(ParallelScavengeHeap::heap()->is_in_reserved(p), "precondition");
318 assert(should_scavenge(p, true), "revisiting object?");
319
320 oop o = RawAccess<IS_NOT_NULL>::oop_load(p);
321 oop new_obj = copy_to_survivor_space<promote_immediately>(o);
322 RawAccess<IS_NOT_NULL>::oop_store(p, new_obj);
323
324 if (!PSScavenge::is_obj_in_young((HeapWord*)p) &&
325 PSScavenge::is_obj_in_young(new_obj)) {
326 PSScavenge::card_table()->inline_write_ref_field_gc(p);
327 }
328 }
329
330 inline void PSPromotionManager::process_popped_location_depth(ScannerTask task) {
331 if (task.is_partial_array_task()) {
332 assert(PSChunkLargeArrays, "invariant");
333 process_array_chunk(task.to_partial_array_task());
334 } else {
335 if (task.is_narrow_oop_ptr()) {
336 assert(UseCompressedOops, "Error");
337 copy_and_push_safe_barrier</*promote_immediately=*/false>(task.to_narrow_oop_ptr());
338 } else {
339 copy_and_push_safe_barrier</*promote_immediately=*/false>(task.to_oop_ptr());
340 }
341 }
342 }
343
344 inline bool PSPromotionManager::steal_depth(int queue_num, ScannerTask& t) {
345 return stack_array_depth()->steal(queue_num, t);
346 }
347
348 #if TASKQUEUE_STATS
349 void PSPromotionManager::record_steal(ScannerTask task) {
350 if (task.is_partial_array_task()) {
351 ++_array_chunk_steals;
352 }
353 }
354 #endif // TASKQUEUE_STATS
355
356 #endif // SHARE_GC_PARALLEL_PSPROMOTIONMANAGER_INLINE_HPP