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.
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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_G1CONCURRENTMARK_INLINE_HPP
26 #define SHARE_VM_GC_G1_G1CONCURRENTMARK_INLINE_HPP
27
28 #include "gc/g1/g1CollectedHeap.inline.hpp"
29 #include "gc/g1/g1ConcurrentMark.hpp"
30 #include "gc/g1/g1ConcurrentMarkObjArrayProcessor.inline.hpp"
31 #include "gc/g1/suspendibleThreadSet.hpp"
32 #include "gc/shared/taskqueue.inline.hpp"
33 #include "utilities/bitMap.inline.hpp"
34
35 inline bool G1ConcurrentMark::par_mark(oop obj) {
36 return _nextMarkBitMap->par_mark((HeapWord*)obj);
37 }
38
39 inline bool G1CMBitMap::iterate(G1CMBitMapClosure* cl, MemRegion mr) {
40 assert(!mr.is_empty(), "Does not support empty memregion to iterate over");
41 assert(_covered.contains(mr), "Given MemRegion from " PTR_FORMAT " to " PTR_FORMAT " not contained in heap area", p2i(mr.start()), p2i(mr.end()));
42
43 BitMap::idx_t const end_offset = addr_to_offset(mr.end());
44 BitMap::idx_t offset = _bm.get_next_one_offset(addr_to_offset(mr.start()), end_offset);
45
46 while (offset < end_offset) {
47 HeapWord* const addr = offset_to_addr(offset);
48 if (!cl->do_addr(addr)) {
49 return false;
50 }
51 size_t const obj_size = (size_t)((oop)addr)->size();
52 offset = _bm.get_next_one_offset(offset + (obj_size >> _shifter), end_offset);
53 }
54 return true;
55 }
56
57 inline HeapWord* G1CMBitMap::get_next_marked_addr(const HeapWord* addr,
58 const HeapWord* limit) const {
59 assert(limit != NULL, "limit must not be NULL");
60 // Round addr up to a possible object boundary to be safe.
61 size_t const addr_offset = addr_to_offset(align_up(addr, HeapWordSize << _shifter));
62 size_t const limit_offset = addr_to_offset(limit);
63 size_t const nextOffset = _bm.get_next_one_offset(addr_offset, limit_offset);
64 return offset_to_addr(nextOffset);
65 }
66
67 #ifdef ASSERT
68 inline void G1CMBitMap::check_mark(HeapWord* addr) {
69 assert(G1CollectedHeap::heap()->is_in_exact(addr),
70 "Trying to access bitmap " PTR_FORMAT " for address " PTR_FORMAT " not in the heap.",
71 p2i(this), p2i(addr));
72 }
73 #endif
74
75 inline void G1CMBitMap::mark(HeapWord* addr) {
76 check_mark(addr);
77 _bm.set_bit(addr_to_offset(addr));
78 }
79
80 inline void G1CMBitMap::clear(HeapWord* addr) {
81 check_mark(addr);
82 _bm.clear_bit(addr_to_offset(addr));
83 }
84
85 inline bool G1CMBitMap::par_mark(HeapWord* addr) {
86 check_mark(addr);
87 return _bm.par_set_bit(addr_to_offset(addr));
88 }
89
90 #ifndef PRODUCT
91 template<typename Fn>
92 inline void G1CMMarkStack::iterate(Fn fn) const {
93 assert_at_safepoint(true);
94
95 size_t num_chunks = 0;
96
97 TaskQueueEntryChunk* cur = _chunk_list;
98 while (cur != NULL) {
99 guarantee(num_chunks <= _chunks_in_chunk_list, "Found " SIZE_FORMAT " oop chunks which is more than there should be", num_chunks);
100
101 for (size_t i = 0; i < EntriesPerChunk; ++i) {
102 if (cur->data[i].is_null()) {
103 break;
104 }
105 fn(cur->data[i]);
106 }
107 cur = cur->next;
108 num_chunks++;
109 }
110 }
111 #endif
112
113 // It scans an object and visits its children.
114 inline void G1CMTask::scan_task_entry(G1TaskQueueEntry task_entry) { process_grey_task_entry<true>(task_entry); }
115
116 inline void G1CMTask::push(G1TaskQueueEntry task_entry) {
117 assert(task_entry.is_array_slice() || _g1h->is_in_g1_reserved(task_entry.obj()), "invariant");
118 assert(task_entry.is_array_slice() || !_g1h->is_on_master_free_list(
119 _g1h->heap_region_containing(task_entry.obj())), "invariant");
120 assert(task_entry.is_array_slice() || !_g1h->is_obj_ill(task_entry.obj()), "invariant"); // FIXME!!!
121 assert(task_entry.is_array_slice() || _nextMarkBitMap->is_marked((HeapWord*)task_entry.obj()), "invariant");
122
123 if (!_task_queue->push(task_entry)) {
124 // The local task queue looks full. We need to push some entries
125 // to the global stack.
126 move_entries_to_global_stack();
127
128 // this should succeed since, even if we overflow the global
129 // stack, we should have definitely removed some entries from the
130 // local queue. So, there must be space on it.
131 bool success = _task_queue->push(task_entry);
132 assert(success, "invariant");
133 }
134 }
135
136 inline bool G1CMTask::is_below_finger(oop obj, HeapWord* global_finger) const {
137 // If obj is above the global finger, then the mark bitmap scan
138 // will find it later, and no push is needed. Similarly, if we have
139 // a current region and obj is between the local finger and the
140 // end of the current region, then no push is needed. The tradeoff
141 // of checking both vs only checking the global finger is that the
142 // local check will be more accurate and so result in fewer pushes,
143 // but may also be a little slower.
144 HeapWord* objAddr = (HeapWord*)obj;
145 if (_finger != NULL) {
146 // We have a current region.
147
148 // Finger and region values are all NULL or all non-NULL. We
149 // use _finger to check since we immediately use its value.
150 assert(_curr_region != NULL, "invariant");
151 assert(_region_limit != NULL, "invariant");
152 assert(_region_limit <= global_finger, "invariant");
153
154 // True if obj is less than the local finger, or is between
155 // the region limit and the global finger.
156 if (objAddr < _finger) {
157 return true;
158 } else if (objAddr < _region_limit) {
159 return false;
160 } // Else check global finger.
161 }
162 // Check global finger.
163 return objAddr < global_finger;
164 }
165
166 template<bool scan>
167 inline void G1CMTask::process_grey_task_entry(G1TaskQueueEntry task_entry) {
168 assert(scan || (task_entry.is_oop() && task_entry.obj()->is_typeArray()), "Skipping scan of grey non-typeArray");
169 assert(task_entry.is_array_slice() || _nextMarkBitMap->is_marked((HeapWord*)task_entry.obj()),
170 "Any stolen object should be a slice or marked");
171
172 if (scan) {
173 if (task_entry.is_array_slice()) {
174 _words_scanned += _objArray_processor.process_slice(task_entry.slice());
175 } else {
176 oop obj = task_entry.obj();
177 if (G1CMObjArrayProcessor::should_be_sliced(obj)) {
178 _words_scanned += _objArray_processor.process_obj(obj);
179 } else {
180 _words_scanned += obj->oop_iterate_size(_cm_oop_closure);;
181 }
182 }
183 }
184 check_limits();
185 }
186
187 inline size_t G1CMTask::scan_objArray(objArrayOop obj, MemRegion mr) {
188 obj->oop_iterate(_cm_oop_closure, mr);
189 return mr.word_size();
190 }
191
192 inline void G1CMTask::make_reference_grey(oop obj) {
193 if (_cm->par_mark(obj)) {
194 // No OrderAccess:store_load() is needed. It is implicit in the
195 // CAS done in G1CMBitMap::parMark() call in the routine above.
196 HeapWord* global_finger = _cm->finger();
197
198 // We only need to push a newly grey object on the mark
199 // stack if it is in a section of memory the mark bitmap
200 // scan has already examined. Mark bitmap scanning
201 // maintains progress "fingers" for determining that.
202 //
203 // Notice that the global finger might be moving forward
204 // concurrently. This is not a problem. In the worst case, we
205 // mark the object while it is above the global finger and, by
206 // the time we read the global finger, it has moved forward
207 // past this object. In this case, the object will probably
208 // be visited when a task is scanning the region and will also
209 // be pushed on the stack. So, some duplicate work, but no
210 // correctness problems.
211 if (is_below_finger(obj, global_finger)) {
212 G1TaskQueueEntry entry = G1TaskQueueEntry::from_oop(obj);
213 if (obj->is_typeArray()) {
214 // Immediately process arrays of primitive types, rather
215 // than pushing on the mark stack. This keeps us from
216 // adding humongous objects to the mark stack that might
217 // be reclaimed before the entry is processed - see
218 // selection of candidates for eager reclaim of humongous
219 // objects. The cost of the additional type test is
220 // mitigated by avoiding a trip through the mark stack,
221 // by only doing a bookkeeping update and avoiding the
222 // actual scan of the object - a typeArray contains no
223 // references, and the metadata is built-in.
224 process_grey_task_entry<false>(entry);
225 } else {
226 push(entry);
227 }
228 }
229 }
230 }
231
232 inline void G1CMTask::deal_with_reference(oop obj) {
233 increment_refs_reached();
234
235 HeapWord* objAddr = (HeapWord*) obj;
236 assert(obj->is_oop_or_null(true /* ignore mark word */), "Expected an oop or NULL at " PTR_FORMAT, p2i(obj));
237 if (_g1h->is_in_g1_reserved(objAddr)) {
238 assert(obj != NULL, "null check is implicit");
239 if (!_nextMarkBitMap->is_marked(objAddr)) {
240 // Only get the containing region if the object is not marked on the
241 // bitmap (otherwise, it's a waste of time since we won't do
242 // anything with it).
243 HeapRegion* hr = _g1h->heap_region_containing(obj);
244 if (!hr->obj_allocated_since_next_marking(obj)) {
245 make_reference_grey(obj);
246 }
247 }
248 }
249 }
250
251 inline void G1ConcurrentMark::markPrev(oop p) {
252 assert(!_prevMarkBitMap->is_marked((HeapWord*) p), "sanity");
253 _prevMarkBitMap->mark((HeapWord*) p);
254 }
255
256 bool G1ConcurrentMark::isPrevMarked(oop p) const {
257 assert(p != NULL && p->is_oop(), "expected an oop");
258 return _prevMarkBitMap->is_marked((HeapWord*)p);
259 }
260
261 inline void G1ConcurrentMark::grayRoot(oop obj, HeapRegion* hr) {
262 assert(obj != NULL, "pre-condition");
263 HeapWord* addr = (HeapWord*) obj;
264 if (hr == NULL) {
265 hr = _g1h->heap_region_containing(addr);
266 } else {
267 assert(hr->is_in(addr), "pre-condition");
268 }
269 assert(hr != NULL, "sanity");
270 // Given that we're looking for a region that contains an object
271 // header it's impossible to get back a HC region.
272 assert(!hr->is_continues_humongous(), "sanity");
273
274 if (addr < hr->next_top_at_mark_start()) {
275 if (!_nextMarkBitMap->is_marked(addr)) {
276 par_mark(obj);
277 }
278 }
279 }
280
281 inline bool G1ConcurrentMark::do_yield_check() {
282 if (SuspendibleThreadSet::should_yield()) {
283 SuspendibleThreadSet::yield();
284 return true;
285 } else {
286 return false;
287 }
288 }
289
290 #endif // SHARE_VM_GC_G1_G1CONCURRENTMARK_INLINE_HPP