1 /*
2 * Copyright (c) 2001, 2017, 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
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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/g1RemSet.inline.hpp"
34 #include "gc/g1/heapRegion.inline.hpp"
35 #include "gc/g1/heapRegionRemSet.hpp"
36 #include "memory/iterator.inline.hpp"
37 #include "runtime/prefetch.inline.hpp"
38
39 // This closure is applied to the fields of the objects that have just been copied.
40 template <class T>
41 inline void G1ParScanClosure::do_oop_nv(T* p) {
42 T heap_oop = oopDesc::load_heap_oop(p);
43
44 if (!oopDesc::is_null(heap_oop)) {
45 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
46 const InCSetState state = _g1->in_cset_state(obj);
47 if (state.is_in_cset()) {
48 // We're not going to even bother checking whether the object is
49 // already forwarded or not, as this usually causes an immediate
50 // stall. We'll try to prefetch the object (for write, given that
51 // we might need to install the forwarding reference) and we'll
52 // get back to it when pop it from the queue
53 Prefetch::write(obj->mark_addr(), 0);
54 Prefetch::read(obj->mark_addr(), (HeapWordSize*2));
55
56 // slightly paranoid test; I'm trying to catch potential
57 // problems before we go into push_on_queue to know where the
58 // problem is coming from
59 assert((obj == oopDesc::load_decode_heap_oop(p)) ||
60 (obj->is_forwarded() &&
61 obj->forwardee() == oopDesc::load_decode_heap_oop(p)),
62 "p should still be pointing to obj or to its forwardee");
63
64 _par_scan_state->push_on_queue(p);
65 } else {
66 if (state.is_humongous()) {
67 _g1->set_humongous_is_live(obj);
68 } else if (state.is_ext()) {
69 _par_scan_state->do_oop_ext(p);
70 }
71 _par_scan_state->update_rs(_from, p, obj);
72 }
73 }
74 }
75
76 template <class T>
77 inline void G1ParPushHeapRSClosure::do_oop_nv(T* p) {
78 T heap_oop = oopDesc::load_heap_oop(p);
79
80 if (!oopDesc::is_null(heap_oop)) {
81 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
82 const InCSetState state = _g1->in_cset_state(obj);
83 if (state.is_in_cset_or_humongous()) {
84 Prefetch::write(obj->mark_addr(), 0);
85 Prefetch::read(obj->mark_addr(), (HeapWordSize*2));
86
87 // Place on the references queue
88 _par_scan_state->push_on_queue(p);
89 } else if (state.is_ext()) {
90 _par_scan_state->do_oop_ext(p);
91 } else {
92 assert(!_g1->is_in_cset(obj), "checking");
93 }
94 }
95 }
96
97 template <class T>
98 inline void G1CMOopClosure::do_oop_nv(T* p) {
99 oop obj = oopDesc::load_decode_heap_oop(p);
100 _task->deal_with_reference(obj);
101 }
102
103 template <class T>
104 inline void G1RootRegionScanClosure::do_oop_nv(T* p) {
105 T heap_oop = oopDesc::load_heap_oop(p);
106 if (!oopDesc::is_null(heap_oop)) {
107 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
108 HeapRegion* hr = _g1h->heap_region_containing((HeapWord*) obj);
109 _cm->grayRoot(obj, hr);
110 }
111 }
112
113 template <class T>
114 inline void G1UpdateRSOrPushRefOopClosure::do_oop_nv(T* p) {
115 oop obj = oopDesc::load_decode_heap_oop(p);
116 if (obj == NULL) {
117 return;
118 }
119
120 #ifdef ASSERT
121 // can't do because of races
122 // assert(obj == NULL || obj->is_oop(), "expected an oop");
123 assert(check_obj_alignment(obj), "not oop aligned");
124 assert(_g1->is_in_reserved(obj), "must be in heap");
125 #endif // ASSERT
126
127 assert(_from != NULL, "from region must be non-NULL");
128 assert(_from->is_in_reserved(p) ||
129 (_from->is_humongous() &&
130 _g1->heap_region_containing(p)->is_humongous() &&
131 _from->humongous_start_region() == _g1->heap_region_containing(p)->humongous_start_region()),
132 "p " PTR_FORMAT " is not in the same region %u or part of the correct humongous object starting at region %u.",
133 p2i(p), _from->hrm_index(), _from->humongous_start_region()->hrm_index());
134
135 HeapRegion* to = _g1->heap_region_containing(obj);
136 if (_from == to) {
137 // Normally this closure should only be called with cross-region references.
138 // But since Java threads are manipulating the references concurrently and we
139 // reload the values things may have changed.
140 // Also this check lets slip through references from a humongous continues region
141 // to its humongous start region, as they are in different regions, and adds a
142 // remembered set entry. This is benign (apart from memory usage), as we never
143 // try to either evacuate or eager reclaim these kind of regions.
144 return;
145 }
146
147 // The _record_refs_into_cset flag is true during the RSet
148 // updating part of an evacuation pause. It is false at all
149 // other times:
150 // * rebuilding the remembered sets after a full GC
151 // * during concurrent refinement.
152 // * updating the remembered sets of regions in the collection
153 // set in the event of an evacuation failure (when deferred
154 // updates are enabled).
155
156 if (_record_refs_into_cset && to->in_collection_set()) {
157 // We are recording references that point into the collection
158 // set and this particular reference does exactly that...
159 // If the referenced object has already been forwarded
160 // to itself, we are handling an evacuation failure and
161 // we have already visited/tried to copy this object
162 // there is no need to retry.
163 if (!self_forwarded(obj)) {
164 assert(_push_ref_cl != NULL, "should not be null");
165 // Push the reference in the refs queue of the G1ParScanThreadState
166 // instance for this worker thread.
167 _push_ref_cl->do_oop(p);
168 }
169 _has_refs_into_cset = true;
170
171 // Deferred updates to the CSet are either discarded (in the normal case),
172 // or processed (if an evacuation failure occurs) at the end
173 // of the collection.
174 // See G1RemSet::cleanup_after_oops_into_collection_set_do().
175 } else {
176 // We either don't care about pushing references that point into the
177 // collection set (i.e. we're not during an evacuation pause) _or_
178 // the reference doesn't point into the collection set. Either way
179 // we add the reference directly to the RSet of the region containing
180 // the referenced object.
181 assert(to->rem_set() != NULL, "Need per-region 'into' remsets.");
182 to->rem_set()->add_reference(p, _worker_i);
183 }
184 }
185 void G1UpdateRSOrPushRefOopClosure::do_oop(oop* p) { do_oop_nv(p); }
186 void G1UpdateRSOrPushRefOopClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
187
188 template <class T>
189 void G1ParCopyHelper::do_klass_barrier(T* p, oop new_obj) {
190 if (_g1->heap_region_containing(new_obj)->is_young()) {
191 _scanned_klass->record_modified_oops();
192 }
193 }
194
195 void G1ParCopyHelper::mark_object(oop obj) {
196 assert(!_g1->heap_region_containing(obj)->in_collection_set(), "should not mark objects in the CSet");
197
198 // We know that the object is not moving so it's safe to read its size.
199 _cm->grayRoot(obj);
200 }
201
202 void G1ParCopyHelper::mark_forwarded_object(oop from_obj, oop to_obj) {
203 assert(from_obj->is_forwarded(), "from obj should be forwarded");
204 assert(from_obj->forwardee() == to_obj, "to obj should be the forwardee");
205 assert(from_obj != to_obj, "should not be self-forwarded");
206
207 assert(_g1->heap_region_containing(from_obj)->in_collection_set(), "from obj should be in the CSet");
208 assert(!_g1->heap_region_containing(to_obj)->in_collection_set(), "should not mark objects in the CSet");
209
210 // The object might be in the process of being copied by another
211 // worker so we cannot trust that its to-space image is
212 // well-formed. So we have to read its size from its from-space
213 // image which we know should not be changing.
214 _cm->grayRoot(to_obj);
215 }
216
217 template <G1Barrier barrier, G1Mark do_mark_object, bool use_ext>
218 template <class T>
219 void G1ParCopyClosure<barrier, do_mark_object, use_ext>::do_oop_work(T* p) {
220 T heap_oop = oopDesc::load_heap_oop(p);
221
222 if (oopDesc::is_null(heap_oop)) {
223 return;
224 }
225
226 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
227
228 assert(_worker_id == _par_scan_state->worker_id(), "sanity");
229
230 const InCSetState state = _g1->in_cset_state(obj);
231 if (state.is_in_cset()) {
232 oop forwardee;
233 markOop m = obj->mark();
234 if (m->is_marked()) {
235 forwardee = (oop) m->decode_pointer();
236 } else {
237 forwardee = _par_scan_state->copy_to_survivor_space(state, obj, m);
238 }
239 assert(forwardee != NULL, "forwardee should not be NULL");
240 oopDesc::encode_store_heap_oop(p, forwardee);
241 if (do_mark_object != G1MarkNone && forwardee != obj) {
242 // If the object is self-forwarded we don't need to explicitly
243 // mark it, the evacuation failure protocol will do so.
244 mark_forwarded_object(obj, forwardee);
245 }
246
247 if (barrier == G1BarrierKlass) {
248 do_klass_barrier(p, forwardee);
249 }
250 } else {
251 if (state.is_humongous()) {
252 _g1->set_humongous_is_live(obj);
253 }
254
255 if (use_ext && state.is_ext()) {
256 _par_scan_state->do_oop_ext(p);
257 }
258 // The object is not in collection set. If we're a root scanning
259 // closure during an initial mark pause then attempt to mark the object.
260 if (do_mark_object == G1MarkFromRoot) {
261 mark_object(obj);
262 }
263 }
264 }
265
266 #endif // SHARE_VM_GC_G1_G1OOPCLOSURES_INLINE_HPP