1 /*
2 * Copyright (c) 2001, 2018, 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_VM_GC_G1_G1OOPCLOSURES_INLINE_HPP
26 #define SHARE_VM_GC_G1_G1OOPCLOSURES_INLINE_HPP
27
28 #include "gc/g1/g1CollectedHeap.hpp"
29 #include "gc/g1/g1ConcurrentMark.inline.hpp"
30 #include "gc/g1/g1OopClosures.hpp"
31 #include "gc/g1/g1ParScanThreadState.inline.hpp"
32 #include "gc/g1/g1RemSet.hpp"
33 #include "gc/g1/heapRegion.inline.hpp"
34 #include "gc/g1/heapRegionRemSet.hpp"
35 #include "memory/iterator.inline.hpp"
36 #include "oops/access.inline.hpp"
37 #include "oops/compressedOops.inline.hpp"
38 #include "oops/oopsHierarchy.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "runtime/prefetch.inline.hpp"
41
42 template <class T>
43 inline void G1ScanClosureBase::prefetch_and_push(T* p, const oop obj) {
44 // We're not going to even bother checking whether the object is
45 // already forwarded or not, as this usually causes an immediate
46 // stall. We'll try to prefetch the object (for write, given that
47 // we might need to install the forwarding reference) and we'll
48 // get back to it when pop it from the queue
49 Prefetch::write(obj->mark_addr_raw(), 0);
50 Prefetch::read(obj->mark_addr_raw(), (HeapWordSize*2));
51
52 // slightly paranoid test; I'm trying to catch potential
53 // problems before we go into push_on_queue to know where the
54 // problem is coming from
55 assert((obj == RawAccess<>::oop_load(p)) ||
56 (obj->is_forwarded() &&
57 obj->forwardee() == RawAccess<>::oop_load(p)),
58 "p should still be pointing to obj or to its forwardee");
59
60 _par_scan_state->push_on_queue(p);
61 }
62
63 template <class T>
64 inline void G1ScanClosureBase::handle_non_cset_obj_common(InCSetState const state, T* p, oop const obj) {
65 if (state.is_humongous()) {
66 _g1h->set_humongous_is_live(obj);
67 } else if (state.is_optional()) {
68 _par_scan_state->remember_reference_into_optional_region(p);
69 }
70 }
71
72 inline void G1ScanClosureBase::trim_queue_partially() {
73 _par_scan_state->trim_queue_partially();
74 }
75
76 template <class T>
77 inline void G1ScanEvacuatedObjClosure::do_oop_work(T* p) {
78 T heap_oop = RawAccess<>::oop_load(p);
79
80 if (CompressedOops::is_null(heap_oop)) {
81 return;
82 }
83 oop obj = CompressedOops::decode_not_null(heap_oop);
84 const InCSetState state = _g1h->in_cset_state(obj);
85 if (state.is_in_cset()) {
86 prefetch_and_push(p, obj);
87 } else if (!HeapRegion::is_in_same_region(p, obj)) {
88 handle_non_cset_obj_common(state, p, obj);
89 assert(_scanning_in_young != Uninitialized, "Scan location has not been initialized.");
90 if (_scanning_in_young == True) {
91 return;
92 }
93 _par_scan_state->enqueue_card_if_tracked(p, obj);
94 }
95 }
96
97 template <class T>
98 inline void G1CMOopClosure::do_oop_work(T* p) {
99 _task->deal_with_reference(p);
100 }
101
102 template <class T>
103 inline void G1RootRegionScanClosure::do_oop_work(T* p) {
104 T heap_oop = RawAccess<MO_VOLATILE>::oop_load(p);
105 if (CompressedOops::is_null(heap_oop)) {
106 return;
107 }
108 oop obj = CompressedOops::decode_not_null(heap_oop);
109 _cm->mark_in_next_bitmap(_worker_id, obj);
110 }
111
112 template <class T>
113 inline static void check_obj_during_refinement(T* p, oop const obj) {
114 #ifdef ASSERT
115 G1CollectedHeap* g1h = G1CollectedHeap::heap();
116 // can't do because of races
117 // assert(oopDesc::is_oop_or_null(obj), "expected an oop");
118 assert(check_obj_alignment(obj), "not oop aligned");
119 assert(g1h->is_in_reserved(obj), "must be in heap");
120
121 HeapRegion* from = g1h->heap_region_containing(p);
122
123 assert(from != NULL, "from region must be non-NULL");
124 assert(from->is_in_reserved(p) ||
125 (from->is_humongous() &&
126 g1h->heap_region_containing(p)->is_humongous() &&
127 from->humongous_start_region() == g1h->heap_region_containing(p)->humongous_start_region()),
128 "p " PTR_FORMAT " is not in the same region %u or part of the correct humongous object starting at region %u.",
129 p2i(p), from->hrm_index(), from->humongous_start_region()->hrm_index());
130 #endif // ASSERT
131 }
132
133 template <class T>
134 inline void G1ConcurrentRefineOopClosure::do_oop_work(T* p) {
135 T o = RawAccess<MO_VOLATILE>::oop_load(p);
136 if (CompressedOops::is_null(o)) {
137 return;
138 }
139 oop obj = CompressedOops::decode_not_null(o);
140
141 check_obj_during_refinement(p, obj);
142
143 if (HeapRegion::is_in_same_region(p, obj)) {
144 // Normally this closure should only be called with cross-region references.
145 // But since Java threads are manipulating the references concurrently and we
146 // reload the values things may have changed.
147 // Also this check lets slip through references from a humongous continues region
148 // to its humongous start region, as they are in different regions, and adds a
149 // remembered set entry. This is benign (apart from memory usage), as we never
150 // try to either evacuate or eager reclaim humonguous arrays of j.l.O.
151 return;
152 }
153
154 HeapRegionRemSet* to_rem_set = _g1h->heap_region_containing(obj)->rem_set();
155
156 assert(to_rem_set != NULL, "Need per-region 'into' remsets.");
157 if (to_rem_set->is_tracked()) {
158 to_rem_set->add_reference(p, _worker_i);
159 }
160 }
161
162 template <class T>
163 inline void G1ScanObjsDuringUpdateRSClosure::do_oop_work(T* p) {
164 T o = RawAccess<>::oop_load(p);
165 if (CompressedOops::is_null(o)) {
166 return;
167 }
168 oop obj = CompressedOops::decode_not_null(o);
169
170 check_obj_during_refinement(p, obj);
171
172 assert(!_g1h->is_in_cset((HeapWord*)p), "Oop originates from " PTR_FORMAT " (region: %u) which is in the collection set.", p2i(p), _g1h->addr_to_region((HeapWord*)p));
173 const InCSetState state = _g1h->in_cset_state(obj);
174 if (state.is_in_cset()) {
175 // Since the source is always from outside the collection set, here we implicitly know
176 // that this is a cross-region reference too.
177 prefetch_and_push(p, obj);
178 } else if (!HeapRegion::is_in_same_region(p, obj)) {
179 handle_non_cset_obj_common(state, p, obj);
180 _par_scan_state->enqueue_card_if_tracked(p, obj);
181 }
182 }
183
184 template <class T>
185 inline void G1ScanObjsDuringScanRSClosure::do_oop_work(T* p) {
186 T heap_oop = RawAccess<>::oop_load(p);
187 if (CompressedOops::is_null(heap_oop)) {
188 return;
189 }
190 oop obj = CompressedOops::decode_not_null(heap_oop);
191
192 const InCSetState state = _g1h->in_cset_state(obj);
193 if (state.is_in_cset()) {
194 prefetch_and_push(p, obj);
195 } else if (!HeapRegion::is_in_same_region(p, obj)) {
196 handle_non_cset_obj_common(state, p, obj);
197 }
198 }
199
200 template <class T>
201 inline void G1ScanRSForOptionalClosure::do_oop_work(T* p) {
202 _scan_cl->do_oop_work(p);
203 _scan_cl->trim_queue_partially();
204 }
205
206 void G1ParCopyHelper::do_cld_barrier(oop new_obj) {
207 if (_g1h->heap_region_containing(new_obj)->is_young()) {
208 _scanned_cld->record_modified_oops();
209 }
210 }
211
212 void G1ParCopyHelper::mark_object(oop obj) {
213 assert(!_g1h->heap_region_containing(obj)->in_collection_set(), "should not mark objects in the CSet");
214
215 // We know that the object is not moving so it's safe to read its size.
216 _cm->mark_in_next_bitmap(_worker_id, obj);
217 }
218
219 void G1ParCopyHelper::mark_forwarded_object(oop from_obj, oop to_obj) {
220 assert(from_obj->is_forwarded(), "from obj should be forwarded");
221 assert(from_obj->forwardee() == to_obj, "to obj should be the forwardee");
222 assert(from_obj != to_obj, "should not be self-forwarded");
223
224 assert(_g1h->heap_region_containing(from_obj)->in_collection_set(), "from obj should be in the CSet");
225 assert(!_g1h->heap_region_containing(to_obj)->in_collection_set(), "should not mark objects in the CSet");
226
227 // The object might be in the process of being copied by another
228 // worker so we cannot trust that its to-space image is
229 // well-formed. So we have to read its size from its from-space
230 // image which we know should not be changing.
231 _cm->mark_in_next_bitmap(_worker_id, to_obj, from_obj->size());
232 }
233
234 void G1ParCopyHelper::trim_queue_partially() {
235 _par_scan_state->trim_queue_partially();
236 }
237
238 template <G1Barrier barrier, G1Mark do_mark_object>
239 template <class T>
240 void G1ParCopyClosure<barrier, do_mark_object>::do_oop_work(T* p) {
241 T heap_oop = RawAccess<>::oop_load(p);
242
243 if (CompressedOops::is_null(heap_oop)) {
244 return;
245 }
246
247 oop obj = CompressedOops::decode_not_null(heap_oop);
248
249 assert(_worker_id == _par_scan_state->worker_id(), "sanity");
250
251 const InCSetState state = _g1h->in_cset_state(obj);
252 if (state.is_in_cset()) {
253 oop forwardee;
254 markOop m = obj->mark_raw();
255 if (m->is_marked()) {
256 forwardee = (oop) m->decode_pointer();
257 } else {
258 forwardee = _par_scan_state->copy_to_survivor_space(state, obj, m);
259 }
260 assert(forwardee != NULL, "forwardee should not be NULL");
261 RawAccess<IS_NOT_NULL>::oop_store(p, forwardee);
262 if (do_mark_object != G1MarkNone && forwardee != obj) {
263 // If the object is self-forwarded we don't need to explicitly
264 // mark it, the evacuation failure protocol will do so.
265 mark_forwarded_object(obj, forwardee);
266 }
267
268 if (barrier == G1BarrierCLD) {
269 do_cld_barrier(forwardee);
270 }
271 } else {
272 if (state.is_humongous()) {
273 _g1h->set_humongous_is_live(obj);
274 } else if (state.is_optional()) {
275 _par_scan_state->remember_root_into_optional_region(p);
276 }
277
278 // The object is not in collection set. If we're a root scanning
279 // closure during an initial mark pause then attempt to mark the object.
280 if (do_mark_object == G1MarkFromRoot) {
281 mark_object(obj);
282 }
283 }
284 trim_queue_partially();
285 }
286
287 template <class T> void G1RebuildRemSetClosure::do_oop_work(T* p) {
288 oop const obj = RawAccess<MO_VOLATILE>::oop_load(p);
289 if (obj == NULL) {
290 return;
291 }
292
293 if (HeapRegion::is_in_same_region(p, obj)) {
294 return;
295 }
296
297 HeapRegion* to = _g1h->heap_region_containing(obj);
298 HeapRegionRemSet* rem_set = to->rem_set();
299 rem_set->add_reference(p, _worker_id);
300 }
301
302 #endif // SHARE_VM_GC_G1_G1OOPCLOSURES_INLINE_HPP