1 /*
2 * Copyright (c) 2001, 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.
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 #ifndef SHARE_GC_G1_G1OOPCLOSURES_INLINE_HPP
26 #define SHARE_GC_G1_G1OOPCLOSURES_INLINE_HPP
27
28 #include "gc/g1/g1OopClosures.hpp"
29
30 #include "gc/g1/g1CollectedHeap.hpp"
31 #include "gc/g1/g1ConcurrentMark.inline.hpp"
32 #include "gc/g1/g1ParScanThreadState.inline.hpp"
33 #include "gc/g1/g1RemSet.hpp"
34 #include "gc/g1/heapRegion.inline.hpp"
35 #include "gc/g1/heapRegionRemSet.inline.hpp"
36 #include "memory/iterator.inline.hpp"
37 #include "oops/access.inline.hpp"
38 #include "oops/compressedOops.inline.hpp"
39 #include "oops/oopsHierarchy.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "runtime/prefetch.inline.hpp"
42 #include "utilities/align.hpp"
43
44 template <class T>
45 inline void G1ScanClosureBase::prefetch_and_push(T* p, const oop obj) {
46 // We're not going to even bother checking whether the object is
47 // already forwarded or not, as this usually causes an immediate
48 // stall. We'll try to prefetch the object (for write, given that
49 // we might need to install the forwarding reference) and we'll
50 // get back to it when pop it from the queue
51 Prefetch::write(obj->mark_addr(), 0);
52 Prefetch::read(obj->mark_addr(), (HeapWordSize*2));
53
54 // slightly paranoid test; I'm trying to catch potential
55 // problems before we go into push_on_queue to know where the
56 // problem is coming from
57 assert((obj == RawAccess<>::oop_load(p)) ||
58 (obj->is_forwarded() &&
59 obj->forwardee() == RawAccess<>::oop_load(p)),
60 "p should still be pointing to obj or to its forwardee");
61
62 _par_scan_state->push_on_queue(ScannerTask(p));
63 }
64
65 template <class T>
66 inline void G1ScanClosureBase::handle_non_cset_obj_common(G1HeapRegionAttr const region_attr, T* p, oop const obj) {
67 if (region_attr.is_humongous()) {
68 _g1h->set_humongous_is_live(obj);
69 } else if (region_attr.is_optional()) {
70 _par_scan_state->remember_reference_into_optional_region(p);
71 }
72 }
73
74 inline void G1ScanClosureBase::trim_queue_partially() {
75 _par_scan_state->trim_queue_partially();
76 }
77
78 template <class T>
79 inline void G1ScanEvacuatedObjClosure::do_oop_work(T* p) {
80 T heap_oop = RawAccess<>::oop_load(p);
81
82 if (CompressedOops::is_null(heap_oop)) {
83 return;
84 }
85 oop obj = CompressedOops::decode_not_null(heap_oop);
86 const G1HeapRegionAttr region_attr = _g1h->region_attr(obj);
87 if (region_attr.is_in_cset()) {
88 prefetch_and_push(p, obj);
89 } else if (!HeapRegion::is_in_same_region(p, obj)) {
90 handle_non_cset_obj_common(region_attr, p, obj);
91 assert(_skip_card_enqueue != Uninitialized, "Scan location has not been initialized.");
92 if (_skip_card_enqueue == True) {
93 return;
94 }
95 _par_scan_state->enqueue_card_if_tracked(region_attr, p, obj);
96 }
97 }
98
99 template <class T>
100 inline void G1CMOopClosure::do_oop_work(T* p) {
101 _task->deal_with_reference(p);
102 }
103
104 template <class T>
105 inline void G1RootRegionScanClosure::do_oop_work(T* p) {
106 T heap_oop = RawAccess<MO_RELAXED>::oop_load(p);
107 if (CompressedOops::is_null(heap_oop)) {
108 return;
109 }
110 oop obj = CompressedOops::decode_not_null(heap_oop);
111 _cm->mark_in_next_bitmap(_worker_id, obj);
112 }
113
114 template <class T>
115 inline static void check_obj_during_refinement(T* p, oop const obj) {
116 #ifdef ASSERT
117 G1CollectedHeap* g1h = G1CollectedHeap::heap();
118 // can't do because of races
119 // assert(oopDesc::is_oop_or_null(obj), "expected an oop");
120 assert(is_object_aligned(obj), "oop must be aligned");
121 assert(g1h->is_in_reserved(obj), "oop must be in reserved");
122
123 HeapRegion* from = g1h->heap_region_containing(p);
124
125 assert(from != NULL, "from region must be non-NULL");
126 assert(from->is_in_reserved(p) ||
127 (from->is_humongous() &&
128 g1h->heap_region_containing(p)->is_humongous() &&
129 from->humongous_start_region() == g1h->heap_region_containing(p)->humongous_start_region()),
130 "p " PTR_FORMAT " is not in the same region %u or part of the correct humongous object starting at region %u.",
131 p2i(p), from->hrm_index(), from->humongous_start_region()->hrm_index());
132 #endif // ASSERT
133 }
134
135 template <class T>
136 inline void G1ConcurrentRefineOopClosure::do_oop_work(T* p) {
137 T o = RawAccess<MO_RELAXED>::oop_load(p);
138 if (CompressedOops::is_null(o)) {
139 return;
140 }
141 oop obj = CompressedOops::decode_not_null(o);
142
143 check_obj_during_refinement(p, obj);
144
145 if (HeapRegion::is_in_same_region(p, obj)) {
146 // Normally this closure should only be called with cross-region references.
147 // But since Java threads are manipulating the references concurrently and we
148 // reload the values things may have changed.
149 // Also this check lets slip through references from a humongous continues region
150 // to its humongous start region, as they are in different regions, and adds a
151 // remembered set entry. This is benign (apart from memory usage), as we never
152 // try to either evacuate or eager reclaim humonguous arrays of j.l.O.
153 return;
154 }
155
156 HeapRegionRemSet* to_rem_set = _g1h->heap_region_containing(obj)->rem_set();
157
158 assert(to_rem_set != NULL, "Need per-region 'into' remsets.");
159 if (to_rem_set->is_tracked()) {
160 to_rem_set->add_reference(p, _worker_id);
161 }
162 }
163
164 template <class T>
165 inline void G1ScanCardClosure::do_oop_work(T* p) {
166 T o = RawAccess<>::oop_load(p);
167 if (CompressedOops::is_null(o)) {
168 return;
169 }
170 oop obj = CompressedOops::decode_not_null(o);
171
172 check_obj_during_refinement(p, obj);
173
174 assert(!_g1h->is_in_cset((HeapWord*)p),
175 "Oop originates from " PTR_FORMAT " (region: %u) which is in the collection set.",
176 p2i(p), _g1h->addr_to_region((HeapWord*)p));
177
178 const G1HeapRegionAttr region_attr = _g1h->region_attr(obj);
179 if (region_attr.is_in_cset()) {
180 // Since the source is always from outside the collection set, here we implicitly know
181 // that this is a cross-region reference too.
182 prefetch_and_push(p, obj);
183 _heap_roots_found++;
184 } else if (!HeapRegion::is_in_same_region(p, obj)) {
185 handle_non_cset_obj_common(region_attr, p, obj);
186 _par_scan_state->enqueue_card_if_tracked(region_attr, p, obj);
187 }
188 }
189
190 template <class T>
191 inline void G1ScanRSForOptionalClosure::do_oop_work(T* p) {
192 const G1HeapRegionAttr region_attr = _g1h->region_attr(p);
193 // Entries in the optional collection set may start to originate from the collection
194 // set after one or more increments. In this case, previously optional regions
195 // became actual collection set regions. Filter them out here.
196 if (region_attr.is_in_cset()) {
197 return;
198 }
199 _scan_cl->do_oop_work(p);
200 _scan_cl->trim_queue_partially();
201 }
202
203 void G1ParCopyHelper::do_cld_barrier(oop new_obj) {
204 if (_g1h->heap_region_containing(new_obj)->is_young()) {
205 _scanned_cld->record_modified_oops();
206 }
207 }
208
209 void G1ParCopyHelper::mark_object(oop obj) {
210 assert(!_g1h->heap_region_containing(obj)->in_collection_set(), "should not mark objects in the CSet");
211
212 // We know that the object is not moving so it's safe to read its size.
213 _cm->mark_in_next_bitmap(_worker_id, obj);
214 }
215
216 void G1ParCopyHelper::trim_queue_partially() {
217 _par_scan_state->trim_queue_partially();
218 }
219
220 template <G1Barrier barrier, bool should_mark>
221 template <class T>
222 void G1ParCopyClosure<barrier, should_mark>::do_oop_work(T* p) {
223 T heap_oop = RawAccess<>::oop_load(p);
224
225 if (CompressedOops::is_null(heap_oop)) {
226 return;
227 }
228
229 oop obj = CompressedOops::decode_not_null(heap_oop);
230
231 assert(_worker_id == _par_scan_state->worker_id(), "sanity");
232
233 const G1HeapRegionAttr state = _g1h->region_attr(obj);
234 if (state.is_in_cset()) {
235 oop forwardee;
236 markWord m = obj->mark();
237 if (m.is_marked()) {
238 forwardee = cast_to_oop(m.decode_pointer());
239 } else {
240 forwardee = _par_scan_state->copy_to_survivor_space(state, obj, m);
241 }
242 assert(forwardee != NULL, "forwardee should not be NULL");
243 RawAccess<IS_NOT_NULL>::oop_store(p, forwardee);
244
245 if (barrier == G1BarrierCLD) {
246 do_cld_barrier(forwardee);
247 }
248 } else {
249 if (state.is_humongous()) {
250 _g1h->set_humongous_is_live(obj);
251 } else if ((barrier != G1BarrierNoOptRoots) && state.is_optional()) {
252 _par_scan_state->remember_root_into_optional_region(p);
253 }
254
255 // The object is not in the collection set. should_mark is true iff the
256 // current closure is applied on strong roots (and weak roots when class
257 // unloading is disabled) in a concurrent mark start pause.
258 if (should_mark) {
259 mark_object(obj);
260 }
261 }
262 trim_queue_partially();
263 }
264
265 template <class T> void G1RebuildRemSetClosure::do_oop_work(T* p) {
266 oop const obj = RawAccess<MO_RELAXED>::oop_load(p);
267 if (obj == NULL) {
268 return;
269 }
270
271 if (HeapRegion::is_in_same_region(p, obj)) {
272 return;
273 }
274
275 HeapRegion* to = _g1h->heap_region_containing(obj);
276 HeapRegionRemSet* rem_set = to->rem_set();
277 rem_set->add_reference(p, _worker_id);
278 }
279
280 #endif // SHARE_GC_G1_G1OOPCLOSURES_INLINE_HPP