1 /*
2 * Copyright (c) 2002, 2021, 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.
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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
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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/shared/taskqueue.inline.hpp"
36 #include "gc/shared/tlab_globals.hpp"
37 #include "logging/log.hpp"
38 #include "memory/iterator.inline.hpp"
39 #include "oops/access.inline.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "runtime/orderAccess.hpp"
42 #include "runtime/prefetch.inline.hpp"
43
44 inline PSPromotionManager* PSPromotionManager::manager_array(uint index) {
45 assert(_manager_array != NULL, "access of NULL manager_array");
46 assert(index <= ParallelGCThreads, "out of range manager_array access");
47 return &_manager_array[index];
48 }
49
50 inline void PSPromotionManager::push_depth(ScannerTask task) {
51 claimed_stack_depth()->push(task);
52 }
53
54 template <class T>
55 inline void PSPromotionManager::claim_or_forward_depth(T* p) {
56 assert(should_scavenge(p, true), "revisiting object?");
57 assert(ParallelScavengeHeap::heap()->is_in(p), "pointer outside heap");
58 oop obj = RawAccess<IS_NOT_NULL>::oop_load(p);
59 Prefetch::write(obj->mark_addr(), 0);
60 push_depth(ScannerTask(p));
61 }
62
63 inline void PSPromotionManager::promotion_trace_event(oop new_obj, oop old_obj,
64 size_t obj_size,
65 uint age, bool tenured,
66 const PSPromotionLAB* lab) {
67 // Skip if memory allocation failed
68 if (new_obj != NULL) {
69 const ParallelScavengeTracer* gc_tracer = PSScavenge::gc_tracer();
70
71 if (lab != NULL) {
72 // Promotion of object through newly allocated PLAB
73 if (gc_tracer->should_report_promotion_in_new_plab_event()) {
74 size_t obj_bytes = obj_size * HeapWordSize;
75 size_t lab_size = lab->capacity();
76 gc_tracer->report_promotion_in_new_plab_event(old_obj->klass(), obj_bytes,
77 age, tenured, lab_size);
78 }
79 } else {
80 // Promotion of object directly to heap
81 if (gc_tracer->should_report_promotion_outside_plab_event()) {
82 size_t obj_bytes = obj_size * HeapWordSize;
83 gc_tracer->report_promotion_outside_plab_event(old_obj->klass(), obj_bytes,
84 age, tenured);
85 }
86 }
87 }
88 }
89
90 class PSPushContentsClosure: public BasicOopIterateClosure {
91 PSPromotionManager* _pm;
92 public:
93 PSPushContentsClosure(PSPromotionManager* pm) : BasicOopIterateClosure(PSScavenge::reference_processor()), _pm(pm) {}
94
95 template <typename T> void do_oop_nv(T* p) {
96 if (PSScavenge::should_scavenge(p)) {
97 _pm->claim_or_forward_depth(p);
98 }
99 }
100
101 virtual void do_oop(oop* p) { do_oop_nv(p); }
102 virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
103 };
104
105 //
106 // This closure specialization will override the one that is defined in
107 // instanceRefKlass.inline.cpp. It swaps the order of oop_oop_iterate and
108 // oop_oop_iterate_ref_processing. Unfortunately G1 and Parallel behaves
109 // significantly better (especially in the Derby benchmark) using opposite
110 // order of these function calls.
111 //
112 template <>
113 inline void InstanceRefKlass::oop_oop_iterate_reverse<oop, PSPushContentsClosure>(oop obj, PSPushContentsClosure* closure) {
114 oop_oop_iterate_ref_processing<oop>(obj, closure);
115 InstanceKlass::oop_oop_iterate_reverse<oop>(obj, closure);
116 }
117
118 template <>
119 inline void InstanceRefKlass::oop_oop_iterate_reverse<narrowOop, PSPushContentsClosure>(oop obj, PSPushContentsClosure* closure) {
120 oop_oop_iterate_ref_processing<narrowOop>(obj, closure);
121 InstanceKlass::oop_oop_iterate_reverse<narrowOop>(obj, closure);
122 }
123
124 inline void PSPromotionManager::push_contents(oop obj) {
125 if (!obj->klass()->is_typeArray_klass()) {
126 PSPushContentsClosure pcc(this);
127 obj->oop_iterate_backwards(&pcc);
128 }
129 }
130
131 template<bool promote_immediately>
132 inline oop PSPromotionManager::copy_to_survivor_space(oop o) {
133 assert(should_scavenge(&o), "Sanity");
134
135 // NOTE! We must be very careful with any methods that access the mark
136 // in o. There may be multiple threads racing on it, and it may be forwarded
137 // at any time.
138 markWord m = o->mark();
139 if (!m.is_marked()) {
140 return copy_unmarked_to_survivor_space<promote_immediately>(o, m);
141 } else {
142 // Ensure any loads from the forwardee follow all changes that precede
143 // the release-cmpxchg that performed the forwarding, possibly in some
144 // other thread.
145 OrderAccess::acquire();
146 // Return the already installed forwardee.
147 return cast_to_oop(m.decode_pointer());
148 }
149 }
150
151 //
152 // This method is pretty bulky. It would be nice to split it up
153 // into smaller submethods, but we need to be careful not to hurt
154 // performance.
155 //
156 template<bool promote_immediately>
157 inline oop PSPromotionManager::copy_unmarked_to_survivor_space(oop o,
158 markWord test_mark) {
159 assert(should_scavenge(&o), "Sanity");
160
161 oop new_obj = NULL;
162 bool new_obj_is_tenured = false;
163 size_t new_obj_size = o->size();
164
165 // Find the objects age, MT safe.
166 uint age = (test_mark.has_displaced_mark_helper() /* o->has_displaced_mark() */) ?
167 test_mark.displaced_mark_helper().age() : test_mark.age();
168
169 if (!promote_immediately) {
170 // Try allocating obj in to-space (unless too old)
171 if (age < PSScavenge::tenuring_threshold()) {
172 new_obj = cast_to_oop(_young_lab.allocate(new_obj_size));
173 if (new_obj == NULL && !_young_gen_is_full) {
174 // Do we allocate directly, or flush and refill?
175 if (new_obj_size > (YoungPLABSize / 2)) {
176 // Allocate this object directly
177 new_obj = cast_to_oop(young_space()->cas_allocate(new_obj_size));
178 promotion_trace_event(new_obj, o, new_obj_size, age, false, NULL);
179 } else {
180 // Flush and fill
181 _young_lab.flush();
182
183 HeapWord* lab_base = young_space()->cas_allocate(YoungPLABSize);
184 if (lab_base != NULL) {
185 _young_lab.initialize(MemRegion(lab_base, YoungPLABSize));
186 // Try the young lab allocation again.
187 new_obj = cast_to_oop(_young_lab.allocate(new_obj_size));
188 promotion_trace_event(new_obj, o, new_obj_size, age, false, &_young_lab);
189 } else {
190 _young_gen_is_full = true;
191 }
192 }
193 }
194 }
195 }
196
197 // Otherwise try allocating obj tenured
198 if (new_obj == NULL) {
199 #ifndef PRODUCT
200 if (ParallelScavengeHeap::heap()->promotion_should_fail()) {
201 return oop_promotion_failed(o, test_mark);
202 }
203 #endif // #ifndef PRODUCT
204
205 new_obj = cast_to_oop(_old_lab.allocate(new_obj_size));
206 new_obj_is_tenured = true;
207
208 if (new_obj == NULL) {
209 if (!_old_gen_is_full) {
210 // Do we allocate directly, or flush and refill?
211 if (new_obj_size > (OldPLABSize / 2)) {
212 // Allocate this object directly
213 new_obj = cast_to_oop(old_gen()->allocate(new_obj_size));
214 promotion_trace_event(new_obj, o, new_obj_size, age, true, NULL);
215 } else {
216 // Flush and fill
217 _old_lab.flush();
218
219 HeapWord* lab_base = old_gen()->allocate(OldPLABSize);
220 if(lab_base != NULL) {
221 #ifdef ASSERT
222 // Delay the initialization of the promotion lab (plab).
223 // This exposes uninitialized plabs to card table processing.
224 if (GCWorkerDelayMillis > 0) {
225 os::naked_sleep(GCWorkerDelayMillis);
226 }
227 #endif
228 _old_lab.initialize(MemRegion(lab_base, OldPLABSize));
229 // Try the old lab allocation again.
230 new_obj = cast_to_oop(_old_lab.allocate(new_obj_size));
231 promotion_trace_event(new_obj, o, new_obj_size, age, true, &_old_lab);
232 }
233 }
234 }
235
236 // This is the promotion failed test, and code handling.
237 // The code belongs here for two reasons. It is slightly
238 // different than the code below, and cannot share the
239 // CAS testing code. Keeping the code here also minimizes
240 // the impact on the common case fast path code.
241
242 if (new_obj == NULL) {
243 _old_gen_is_full = true;
244 return oop_promotion_failed(o, test_mark);
245 }
246 }
247 }
248
249 assert(new_obj != NULL, "allocation should have succeeded");
250
251 // Copy obj
252 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(o), cast_from_oop<HeapWord*>(new_obj), new_obj_size);
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 == NULL) { // 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 log_develop_trace(gc, scavenge)("{%s %s " PTR_FORMAT " -> " PTR_FORMAT " (%d)}",
270 new_obj_is_tenured ? "copying" : "tenuring",
271 new_obj->klass()->internal_name(),
272 p2i((void *)o), p2i((void *)new_obj), new_obj->size());
273
274 // Do the size comparison first with new_obj_size, which we
275 // already have. Hopefully, only a few objects are larger than
276 // _min_array_size_for_chunking, and most of them will be arrays.
277 // So, the is->objArray() test would be very infrequent.
278 if (new_obj_size > _min_array_size_for_chunking &&
279 new_obj->is_objArray() &&
280 PSChunkLargeArrays) {
281 // we'll chunk it
282 push_depth(ScannerTask(PartialArrayScanTask(o)));
283 TASKQUEUE_STATS_ONLY(++_arrays_chunked; ++_array_chunk_pushes);
284 } else {
285 // we'll just push its contents
286 push_contents(new_obj);
287 }
288 return new_obj;
289 } else {
290 // We lost, someone else "owns" this object.
291 // Ensure loads from the forwardee follow all changes that preceeded the
292 // release-cmpxchg that performed the forwarding in another thread.
293 OrderAccess::acquire();
294
295 assert(o->is_forwarded(), "Object must be forwarded if the cas failed.");
296 assert(o->forwardee() == forwardee, "invariant");
297
298 // Try to deallocate the space. If it was directly allocated we cannot
299 // deallocate it, so we have to test. If the deallocation fails,
300 // overwrite with a filler object.
301 if (new_obj_is_tenured) {
302 if (!_old_lab.unallocate_object(cast_from_oop<HeapWord*>(new_obj), new_obj_size)) {
303 CollectedHeap::fill_with_object(cast_from_oop<HeapWord*>(new_obj), new_obj_size);
304 }
305 } else if (!_young_lab.unallocate_object(cast_from_oop<HeapWord*>(new_obj), new_obj_size)) {
306 CollectedHeap::fill_with_object(cast_from_oop<HeapWord*>(new_obj), new_obj_size);
307 }
308 return forwardee;
309 }
310 }
311
312 // Attempt to "claim" oop at p via CAS, push the new obj if successful
313 // This version tests the oop* to make sure it is within the heap before
314 // attempting marking.
315 template <bool promote_immediately, class T>
316 inline void PSPromotionManager::copy_and_push_safe_barrier(T* p) {
317 assert(should_scavenge(p, true), "revisiting object?");
318
319 oop o = RawAccess<IS_NOT_NULL>::oop_load(p);
320 oop new_obj = copy_to_survivor_space<promote_immediately>(o);
321 RawAccess<IS_NOT_NULL>::oop_store(p, new_obj);
322
323 // We cannot mark without test, as some code passes us pointers
324 // that are outside the heap. These pointers are either from roots
325 // or from metadata.
326 if ((!PSScavenge::is_obj_in_young((HeapWord*)p)) &&
327 ParallelScavengeHeap::heap()->is_in_reserved(p)) {
328 if (PSScavenge::is_obj_in_young(new_obj)) {
329 PSScavenge::card_table()->inline_write_ref_field_gc(p, new_obj);
330 }
331 }
332 }
333
334 inline void PSPromotionManager::process_popped_location_depth(ScannerTask task) {
335 if (task.is_partial_array_task()) {
336 assert(PSChunkLargeArrays, "invariant");
337 process_array_chunk(task.to_partial_array_task());
338 } else {
339 if (task.is_narrow_oop_ptr()) {
340 assert(UseCompressedOops, "Error");
341 copy_and_push_safe_barrier</*promote_immediately=*/false>(task.to_narrow_oop_ptr());
342 } else {
343 copy_and_push_safe_barrier</*promote_immediately=*/false>(task.to_oop_ptr());
344 }
345 }
346 }
347
348 inline bool PSPromotionManager::steal_depth(int queue_num, ScannerTask& t) {
349 return stack_array_depth()->steal(queue_num, t);
350 }
351
352 #if TASKQUEUE_STATS
353 void PSPromotionManager::record_steal(ScannerTask task) {
354 if (task.is_partial_array_task()) {
355 ++_array_chunk_steals;
356 }
357 }
358 #endif // TASKQUEUE_STATS
359
360 #endif // SHARE_GC_PARALLEL_PSPROMOTIONMANAGER_INLINE_HPP