1 /*
2 * Copyright (c) 2002, 2022, Oracle and/or its affiliates. All rights reserved.
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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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 *
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23 */
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/taskqueue.inline.hpp"
37 #include "gc/shared/tlab_globals.hpp"
38 #include "logging/log.hpp"
39 #include "memory/iterator.inline.hpp"
40 #include "oops/access.inline.hpp"
41 #include "oops/oop.inline.hpp"
42 #include "runtime/orderAccess.hpp"
43 #include "runtime/prefetch.inline.hpp"
44
45 inline PSPromotionManager* PSPromotionManager::manager_array(uint index) {
46 assert(_manager_array != NULL, "access of NULL manager_array");
47 assert(index < ParallelGCThreads, "out of range manager_array access");
48 return &_manager_array[index];
49 }
50
51 inline void PSPromotionManager::push_depth(ScannerTask task) {
52 claimed_stack_depth()->push(task);
53 }
54
55 template <class T>
56 inline void PSPromotionManager::claim_or_forward_depth(T* p) {
57 assert(should_scavenge(p, true), "revisiting object?");
58 assert(ParallelScavengeHeap::heap()->is_in(p), "pointer outside heap");
59 oop obj = RawAccess<IS_NOT_NULL>::oop_load(p);
60 Prefetch::write(obj->mark_addr(), 0);
61 push_depth(ScannerTask(p));
62 }
63
64 inline void PSPromotionManager::promotion_trace_event(oop new_obj, oop old_obj,
65 size_t obj_size,
66 uint age, bool tenured,
67 const PSPromotionLAB* lab) {
68 // Skip if memory allocation failed
69 if (new_obj != NULL) {
70 const ParallelScavengeTracer* gc_tracer = PSScavenge::gc_tracer();
71
72 if (lab != NULL) {
73 // Promotion of object through newly allocated PLAB
74 if (gc_tracer->should_report_promotion_in_new_plab_event()) {
75 size_t obj_bytes = obj_size * HeapWordSize;
76 size_t lab_size = lab->capacity();
77 gc_tracer->report_promotion_in_new_plab_event(old_obj->klass(), obj_bytes,
78 age, tenured, lab_size);
79 }
80 } else {
81 // Promotion of object directly to heap
82 if (gc_tracer->should_report_promotion_outside_plab_event()) {
83 size_t obj_bytes = obj_size * HeapWordSize;
84 gc_tracer->report_promotion_outside_plab_event(old_obj->klass(), obj_bytes,
85 age, tenured);
86 }
87 }
88 }
89 }
90
91 class PSPushContentsClosure: public BasicOopIterateClosure {
92 PSPromotionManager* _pm;
93 public:
94 PSPushContentsClosure(PSPromotionManager* pm) : BasicOopIterateClosure(PSScavenge::reference_processor()), _pm(pm) {}
95
96 template <typename T> void do_oop_nv(T* p) {
97 if (PSScavenge::should_scavenge(p)) {
98 _pm->claim_or_forward_depth(p);
99 }
100 }
101
102 virtual void do_oop(oop* p) { do_oop_nv(p); }
103 virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
104 };
105
106 //
107 // This closure specialization will override the one that is defined in
108 // instanceRefKlass.inline.cpp. It swaps the order of oop_oop_iterate and
109 // oop_oop_iterate_ref_processing. Unfortunately G1 and Parallel behaves
110 // significantly better (especially in the Derby benchmark) using opposite
111 // order of these function calls.
112 //
113 template <>
114 inline void InstanceRefKlass::oop_oop_iterate_reverse<oop, PSPushContentsClosure>(oop obj, PSPushContentsClosure* closure) {
115 oop_oop_iterate_ref_processing<oop>(obj, closure);
116 InstanceKlass::oop_oop_iterate_reverse<oop>(obj, closure);
117 }
118
119 template <>
120 inline void InstanceRefKlass::oop_oop_iterate_reverse<narrowOop, PSPushContentsClosure>(oop obj, PSPushContentsClosure* closure) {
121 oop_oop_iterate_ref_processing<narrowOop>(obj, closure);
122 InstanceKlass::oop_oop_iterate_reverse<narrowOop>(obj, closure);
123 }
124
125 inline void PSPromotionManager::push_contents(oop obj) {
126 if (!obj->klass()->is_typeArray_klass()) {
127 PSPushContentsClosure pcc(this);
128 obj->oop_iterate_backwards(&pcc);
129 }
130 }
131
132 template<bool promote_immediately>
133 inline oop PSPromotionManager::copy_to_survivor_space(oop o) {
134 assert(should_scavenge(&o), "Sanity");
135
136 // NOTE! We must be very careful with any methods that access the mark
137 // in o. There may be multiple threads racing on it, and it may be forwarded
138 // at any time.
139 markWord m = o->mark();
140 if (!m.is_marked()) {
141 return copy_unmarked_to_survivor_space<promote_immediately>(o, m);
142 } else {
143 // Ensure any loads from the forwardee follow all changes that precede
144 // the release-cmpxchg that performed the forwarding, possibly in some
145 // other thread.
146 OrderAccess::acquire();
147 // Return the already installed forwardee.
148 return cast_to_oop(m.decode_pointer());
149 }
150 }
151
152 //
153 // This method is pretty bulky. It would be nice to split it up
154 // into smaller submethods, but we need to be careful not to hurt
155 // performance.
156 //
157 template<bool promote_immediately>
158 inline oop PSPromotionManager::copy_unmarked_to_survivor_space(oop o,
159 markWord test_mark) {
160 assert(should_scavenge(&o), "Sanity");
161
162 oop new_obj = NULL;
163 bool new_obj_is_tenured = false;
164 size_t new_obj_size = o->size();
165
166 // Find the objects age, MT safe.
167 uint age = (test_mark.has_displaced_mark_helper() /* o->has_displaced_mark() */) ?
168 test_mark.displaced_mark_helper().age() : test_mark.age();
169
170 if (!promote_immediately) {
171 // Try allocating obj in to-space (unless too old)
172 if (age < PSScavenge::tenuring_threshold()) {
173 new_obj = cast_to_oop(_young_lab.allocate(new_obj_size));
174 if (new_obj == NULL && !_young_gen_is_full) {
175 // Do we allocate directly, or flush and refill?
176 if (new_obj_size > (YoungPLABSize / 2)) {
177 // Allocate this object directly
178 new_obj = cast_to_oop(young_space()->cas_allocate(new_obj_size));
179 promotion_trace_event(new_obj, o, new_obj_size, age, false, NULL);
180 } else {
181 // Flush and fill
182 _young_lab.flush();
183
184 HeapWord* lab_base = young_space()->cas_allocate(YoungPLABSize);
185 if (lab_base != NULL) {
186 _young_lab.initialize(MemRegion(lab_base, YoungPLABSize));
187 // Try the young lab allocation again.
188 new_obj = cast_to_oop(_young_lab.allocate(new_obj_size));
189 promotion_trace_event(new_obj, o, new_obj_size, age, false, &_young_lab);
190 } else {
191 _young_gen_is_full = true;
192 }
193 }
194 }
195 }
196 }
197
198 // Otherwise try allocating obj tenured
199 if (new_obj == NULL) {
200 #ifndef PRODUCT
201 if (ParallelScavengeHeap::heap()->promotion_should_fail()) {
202 return oop_promotion_failed(o, test_mark);
203 }
204 #endif // #ifndef PRODUCT
205
206 new_obj = cast_to_oop(_old_lab.allocate(new_obj_size));
207 new_obj_is_tenured = true;
208
209 if (new_obj == NULL) {
210 if (!_old_gen_is_full) {
211 // Do we allocate directly, or flush and refill?
212 if (new_obj_size > (OldPLABSize / 2)) {
213 // Allocate this object directly
214 new_obj = cast_to_oop(old_gen()->allocate(new_obj_size));
215 promotion_trace_event(new_obj, o, new_obj_size, age, true, NULL);
216 } else {
217 // Flush and fill
218 _old_lab.flush();
219
220 HeapWord* lab_base = old_gen()->allocate(OldPLABSize);
221 if(lab_base != NULL) {
222 _old_lab.initialize(MemRegion(lab_base, OldPLABSize));
223 // Try the old lab allocation again.
224 new_obj = cast_to_oop(_old_lab.allocate(new_obj_size));
225 promotion_trace_event(new_obj, o, new_obj_size, age, true, &_old_lab);
226 }
227 }
228 }
229
230 // This is the promotion failed test, and code handling.
231 // The code belongs here for two reasons. It is slightly
232 // different than the code below, and cannot share the
233 // CAS testing code. Keeping the code here also minimizes
234 // the impact on the common case fast path code.
235
236 if (new_obj == NULL) {
237 _old_gen_is_full = true;
238 return oop_promotion_failed(o, test_mark);
239 }
240 }
241 }
242
243 assert(new_obj != NULL, "allocation should have succeeded");
244
245 // Copy obj
246 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(o), cast_from_oop<HeapWord*>(new_obj), new_obj_size);
247
248 // Now we have to CAS in the header.
249 // Make copy visible to threads reading the forwardee.
250 oop forwardee = o->forward_to_atomic(new_obj, test_mark, memory_order_release);
251 if (forwardee == NULL) { // forwardee is NULL when forwarding is successful
252 // We won any races, we "own" this object.
253 assert(new_obj == o->forwardee(), "Sanity");
254
255 // Increment age if obj still in new generation. Now that
256 // we're dealing with a markWord that cannot change, it is
257 // okay to use the non mt safe oop methods.
258 if (!new_obj_is_tenured) {
259 new_obj->incr_age();
260 assert(young_space()->contains(new_obj), "Attempt to push non-promoted obj");
261 }
262
263 // Do the size comparison first with new_obj_size, which we
264 // already have. Hopefully, only a few objects are larger than
265 // _min_array_size_for_chunking, and most of them will be arrays.
266 // So, the is->objArray() test would be very infrequent.
267 if (new_obj_size > _min_array_size_for_chunking &&
268 new_obj->is_objArray() &&
269 PSChunkLargeArrays) {
270 // we'll chunk it
271 push_depth(ScannerTask(PartialArrayScanTask(o)));
272 TASKQUEUE_STATS_ONLY(++_arrays_chunked; ++_array_chunk_pushes);
273 } else {
274 // we'll just push its contents
275 push_contents(new_obj);
276
277 if (StringDedup::is_enabled() &&
278 java_lang_String::is_instance(new_obj) &&
279 psStringDedup::is_candidate_from_evacuation(new_obj, new_obj_is_tenured)) {
280 _string_dedup_requests.add(o);
281 }
282 }
283 return new_obj;
284 } else {
285 // We lost, someone else "owns" this object.
286 // Ensure loads from the forwardee follow all changes that preceded the
287 // release-cmpxchg that performed the forwarding in another thread.
288 OrderAccess::acquire();
289
290 assert(o->is_forwarded(), "Object must be forwarded if the cas failed.");
291 assert(o->forwardee() == forwardee, "invariant");
292
293 if (new_obj_is_tenured) {
294 _old_lab.unallocate_object(cast_from_oop<HeapWord*>(new_obj), new_obj_size);
295 } else {
296 _young_lab.unallocate_object(cast_from_oop<HeapWord*>(new_obj), new_obj_size);
297 }
298 return forwardee;
299 }
300 }
301
302 // Attempt to "claim" oop at p via CAS, push the new obj if successful
303 template <bool promote_immediately, class T>
304 inline void PSPromotionManager::copy_and_push_safe_barrier(T* p) {
305 assert(ParallelScavengeHeap::heap()->is_in_reserved(p), "precondition");
306 assert(should_scavenge(p, true), "revisiting object?");
307
308 oop o = RawAccess<IS_NOT_NULL>::oop_load(p);
309 oop new_obj = copy_to_survivor_space<promote_immediately>(o);
310 RawAccess<IS_NOT_NULL>::oop_store(p, new_obj);
311
312 if (!PSScavenge::is_obj_in_young((HeapWord*)p) &&
313 PSScavenge::is_obj_in_young(new_obj)) {
314 PSScavenge::card_table()->inline_write_ref_field_gc(p, new_obj);
315 }
316 }
317
318 inline void PSPromotionManager::process_popped_location_depth(ScannerTask task) {
319 if (task.is_partial_array_task()) {
320 assert(PSChunkLargeArrays, "invariant");
321 process_array_chunk(task.to_partial_array_task());
322 } else {
323 if (task.is_narrow_oop_ptr()) {
324 assert(UseCompressedOops, "Error");
325 copy_and_push_safe_barrier</*promote_immediately=*/false>(task.to_narrow_oop_ptr());
326 } else {
327 copy_and_push_safe_barrier</*promote_immediately=*/false>(task.to_oop_ptr());
328 }
329 }
330 }
331
332 inline bool PSPromotionManager::steal_depth(int queue_num, ScannerTask& t) {
333 return stack_array_depth()->steal(queue_num, t);
334 }
335
336 #if TASKQUEUE_STATS
337 void PSPromotionManager::record_steal(ScannerTask task) {
338 if (task.is_partial_array_task()) {
339 ++_array_chunk_steals;
340 }
341 }
342 #endif // TASKQUEUE_STATS
343
344 #endif // SHARE_GC_PARALLEL_PSPROMOTIONMANAGER_INLINE_HPP
--- EOF ---