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),
42 "Given MemRegion from " PTR_FORMAT " to " PTR_FORMAT " not contained in heap area",
43 p2i(mr.start()), p2i(mr.end()));
44
45 BitMap::idx_t const end_offset = addr_to_offset(mr.end());
46 BitMap::idx_t offset = _bm.get_next_one_offset(addr_to_offset(mr.start()), end_offset);
47
48 while (offset < end_offset) {
49 HeapWord* const addr = offset_to_addr(offset);
50 if (!cl->do_addr(addr)) {
51 return false;
52 }
53 size_t const obj_size = (size_t)((oop)addr)->size();
54 offset = _bm.get_next_one_offset(offset + (obj_size >> _shifter), end_offset);
55 }
56 return true;
57 }
58
59 inline HeapWord* G1CMBitMap::get_next_marked_addr(const HeapWord* addr,
60 const HeapWord* limit) const {
61 assert(limit != NULL, "limit must not be NULL");
62 // Round addr up to a possible object boundary to be safe.
63 size_t const addr_offset = addr_to_offset(align_up(addr, HeapWordSize << _shifter));
64 size_t const limit_offset = addr_to_offset(limit);
65 size_t const nextOffset = _bm.get_next_one_offset(addr_offset, limit_offset);
66 return offset_to_addr(nextOffset);
67 }
68
69 #ifdef ASSERT
70 inline void G1CMBitMap::check_mark(HeapWord* addr) {
71 assert(G1CollectedHeap::heap()->is_in_exact(addr),
72 "Trying to access bitmap " PTR_FORMAT " for address " PTR_FORMAT " not in the heap.",
73 p2i(this), p2i(addr));
74 }
75 #endif
76
77 inline void G1CMBitMap::mark(HeapWord* addr) {
78 check_mark(addr);
79 _bm.set_bit(addr_to_offset(addr));
80 }
81
82 inline void G1CMBitMap::clear(HeapWord* addr) {
83 check_mark(addr);
84 _bm.clear_bit(addr_to_offset(addr));
85 }
86
87 inline bool G1CMBitMap::par_mark(HeapWord* addr) {
88 check_mark(addr);
89 return _bm.par_set_bit(addr_to_offset(addr));
90 }
91
92 #ifndef PRODUCT
93 template<typename Fn>
94 inline void G1CMMarkStack::iterate(Fn fn) const {
95 assert_at_safepoint(true);
96
97 size_t num_chunks = 0;
98
99 TaskQueueEntryChunk* cur = _chunk_list;
100 while (cur != NULL) {
101 guarantee(num_chunks <= _chunks_in_chunk_list, "Found " SIZE_FORMAT " oop chunks which is more than there should be", num_chunks);
102
103 for (size_t i = 0; i < EntriesPerChunk; ++i) {
104 if (cur->data[i].is_null()) {
105 break;
106 }
107 fn(cur->data[i]);
108 }
109 cur = cur->next;
110 num_chunks++;
111 }
112 }
113 #endif
114
115 // It scans an object and visits its children.
116 inline void G1CMTask::scan_task_entry(G1TaskQueueEntry task_entry) { process_grey_task_entry<true>(task_entry); }
117
118 inline void G1CMTask::push(G1TaskQueueEntry task_entry) {
119 assert(task_entry.is_array_slice() || _g1h->is_in_g1_reserved(task_entry.obj()), "invariant");
120 assert(task_entry.is_array_slice() || !_g1h->is_on_master_free_list(
121 _g1h->heap_region_containing(task_entry.obj())), "invariant");
122 assert(task_entry.is_array_slice() || !_g1h->is_obj_ill(task_entry.obj()), "invariant"); // FIXME!!!
123 assert(task_entry.is_array_slice() || _nextMarkBitMap->is_marked((HeapWord*)task_entry.obj()), "invariant");
124
125 if (!_task_queue->push(task_entry)) {
126 // The local task queue looks full. We need to push some entries
127 // to the global stack.
128 move_entries_to_global_stack();
129
130 // this should succeed since, even if we overflow the global
131 // stack, we should have definitely removed some entries from the
132 // local queue. So, there must be space on it.
133 bool success = _task_queue->push(task_entry);
134 assert(success, "invariant");
135 }
136 }
137
138 inline bool G1CMTask::is_below_finger(oop obj, HeapWord* global_finger) const {
139 // If obj is above the global finger, then the mark bitmap scan
140 // will find it later, and no push is needed. Similarly, if we have
141 // a current region and obj is between the local finger and the
142 // end of the current region, then no push is needed. The tradeoff
143 // of checking both vs only checking the global finger is that the
144 // local check will be more accurate and so result in fewer pushes,
145 // but may also be a little slower.
146 HeapWord* objAddr = (HeapWord*)obj;
147 if (_finger != NULL) {
148 // We have a current region.
149
150 // Finger and region values are all NULL or all non-NULL. We
151 // use _finger to check since we immediately use its value.
152 assert(_curr_region != NULL, "invariant");
153 assert(_region_limit != NULL, "invariant");
154 assert(_region_limit <= global_finger, "invariant");
155
156 // True if obj is less than the local finger, or is between
157 // the region limit and the global finger.
158 if (objAddr < _finger) {
159 return true;
160 } else if (objAddr < _region_limit) {
161 return false;
162 } // Else check global finger.
163 }
164 // Check global finger.
165 return objAddr < global_finger;
166 }
167
168 template<bool scan>
169 inline void G1CMTask::process_grey_task_entry(G1TaskQueueEntry task_entry) {
170 assert(scan || (task_entry.is_oop() && task_entry.obj()->is_typeArray()), "Skipping scan of grey non-typeArray");
171 assert(task_entry.is_array_slice() || _nextMarkBitMap->is_marked((HeapWord*)task_entry.obj()),
172 "Any stolen object should be a slice or marked");
173
174 if (scan) {
175 if (task_entry.is_array_slice()) {
176 _words_scanned += _objArray_processor.process_slice(task_entry.slice());
177 } else {
178 oop obj = task_entry.obj();
179 if (G1CMObjArrayProcessor::should_be_sliced(obj)) {
180 _words_scanned += _objArray_processor.process_obj(obj);
181 } else {
182 _words_scanned += obj->oop_iterate_size(_cm_oop_closure);;
183 }
184 }
185 }
186 check_limits();
187 }
188
189 inline size_t G1CMTask::scan_objArray(objArrayOop obj, MemRegion mr) {
190 obj->oop_iterate(_cm_oop_closure, mr);
191 return mr.word_size();
192 }
193
194 inline void G1CMTask::make_reference_grey(oop obj) {
195 if (_cm->par_mark(obj)) {
196 // No OrderAccess:store_load() is needed. It is implicit in the
197 // CAS done in G1CMBitMap::parMark() call in the routine above.
198 HeapWord* global_finger = _cm->finger();
199
200 // We only need to push a newly grey object on the mark
201 // stack if it is in a section of memory the mark bitmap
202 // scan has already examined. Mark bitmap scanning
203 // maintains progress "fingers" for determining that.
204 //
205 // Notice that the global finger might be moving forward
206 // concurrently. This is not a problem. In the worst case, we
207 // mark the object while it is above the global finger and, by
208 // the time we read the global finger, it has moved forward
209 // past this object. In this case, the object will probably
210 // be visited when a task is scanning the region and will also
211 // be pushed on the stack. So, some duplicate work, but no
212 // correctness problems.
213 if (is_below_finger(obj, global_finger)) {
214 G1TaskQueueEntry entry = G1TaskQueueEntry::from_oop(obj);
215 if (obj->is_typeArray()) {
216 // Immediately process arrays of primitive types, rather
217 // than pushing on the mark stack. This keeps us from
218 // adding humongous objects to the mark stack that might
219 // be reclaimed before the entry is processed - see
220 // selection of candidates for eager reclaim of humongous
221 // objects. The cost of the additional type test is
222 // mitigated by avoiding a trip through the mark stack,
223 // by only doing a bookkeeping update and avoiding the
224 // actual scan of the object - a typeArray contains no
225 // references, and the metadata is built-in.
226 process_grey_task_entry<false>(entry);
227 } else {
228 push(entry);
229 }
230 }
231 }
232 }
233
234 inline void G1CMTask::deal_with_reference(oop obj) {
235 increment_refs_reached();
236
237 HeapWord* objAddr = (HeapWord*) obj;
238 assert(obj->is_oop_or_null(true /* ignore mark word */), "Expected an oop or NULL at " PTR_FORMAT, p2i(obj));
239 if (_g1h->is_in_g1_reserved(objAddr)) {
240 assert(obj != NULL, "null check is implicit");
241 if (!_nextMarkBitMap->is_marked(objAddr)) {
242 // Only get the containing region if the object is not marked on the
243 // bitmap (otherwise, it's a waste of time since we won't do
244 // anything with it).
245 HeapRegion* hr = _g1h->heap_region_containing(obj);
246 if (!hr->obj_allocated_since_next_marking(obj)) {
247 make_reference_grey(obj);
248 }
249 }
250 }
251 }
252
253 inline void G1ConcurrentMark::markPrev(oop p) {
254 assert(!_prevMarkBitMap->is_marked((HeapWord*) p), "sanity");
255 _prevMarkBitMap->mark((HeapWord*) p);
256 }
257
258 bool G1ConcurrentMark::isPrevMarked(oop p) const {
259 assert(p != NULL && p->is_oop(), "expected an oop");
260 return _prevMarkBitMap->is_marked((HeapWord*)p);
261 }
262
263 inline void G1ConcurrentMark::grayRoot(oop obj, HeapRegion* hr) {
264 assert(obj != NULL, "pre-condition");
265 HeapWord* addr = (HeapWord*) obj;
266 if (hr == NULL) {
267 hr = _g1h->heap_region_containing(addr);
268 } else {
269 assert(hr->is_in(addr), "pre-condition");
270 }
271 assert(hr != NULL, "sanity");
272 // Given that we're looking for a region that contains an object
273 // header it's impossible to get back a HC region.
274 assert(!hr->is_continues_humongous(), "sanity");
275
276 if (addr < hr->next_top_at_mark_start()) {
277 if (!_nextMarkBitMap->is_marked(addr)) {
278 par_mark(obj);
279 }
280 }
281 }
282
283 inline bool G1ConcurrentMark::do_yield_check() {
284 if (SuspendibleThreadSet::should_yield()) {
285 SuspendibleThreadSet::yield();
286 return true;
287 } else {
288 return false;
289 }
290 }
291
292 #endif // SHARE_VM_GC_G1_G1CONCURRENTMARK_INLINE_HPP