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
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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 HeapWord* start_addr = MAX2(_covered.start(), mr.start());
41 HeapWord* const end_addr = MIN2(_covered.end(), mr.end());
42
43 if (end_addr > start_addr) {
44 // Right-open interval [start-offset, end-offset).
45 BitMap::idx_t start_offset = addr_to_offset(start_addr);
46 BitMap::idx_t const end_offset = addr_to_offset(end_addr);
47
48 start_offset = _bm.get_next_one_offset(start_offset, end_offset);
49 while (start_offset < end_offset) {
50 start_addr = offset_to_addr(start_offset);
51 if (!cl->do_addr(start_addr)) {
52 return false;
53 }
54 HeapWord* next_addr = MIN2(addr_after_obj(start_addr), end_addr);
55 BitMap::idx_t const next_offset = addr_to_offset(next_addr);
56 start_offset = _bm.get_next_one_offset(next_offset, end_offset);
57 }
58 }
59 return true;
60 }
61
62 inline HeapWord* G1CMBitMap::get_next_marked_addr(const HeapWord* addr,
63 const HeapWord* limit) const {
64 // First we must round addr *up* to a possible object boundary.
65 addr = (HeapWord*)align_up(addr, HeapWordSize << _shifter);
66 size_t addrOffset = addr_to_offset(addr);
67 assert(limit != NULL, "limit must not be NULL");
68 size_t limitOffset = addr_to_offset(limit);
69 size_t nextOffset = _bm.get_next_one_offset(addrOffset, limitOffset);
70 HeapWord* nextAddr = offset_to_addr(nextOffset);
71 assert(nextAddr >= addr, "get_next_one postcondition");
72 assert(nextAddr == limit || is_marked(nextAddr),
73 "get_next_one postcondition");
74 return nextAddr;
75 }
76
77 inline HeapWord* G1CMBitMap::addr_after_obj(HeapWord* addr) {
78 return addr + ((oop)addr)->size();
79 }
80
81 #ifdef ASSERT
82 inline void G1CMBitMap::check_mark(HeapWord* addr) {
83 assert(G1CollectedHeap::heap()->is_in_exact(addr),
84 "Trying to access bitmap " PTR_FORMAT " for address " PTR_FORMAT " not in the heap.",
85 p2i(this), p2i(addr));
86 }
87 #endif
88
89 inline void G1CMBitMap::mark(HeapWord* addr) {
90 check_mark(addr);
91 _bm.set_bit(addr_to_offset(addr));
92 }
93
94 inline void G1CMBitMap::clear(HeapWord* addr) {
95 check_mark(addr);
96 _bm.clear_bit(addr_to_offset(addr));
97 }
98
99 inline bool G1CMBitMap::par_mark(HeapWord* addr) {
100 check_mark(addr);
101 return _bm.par_set_bit(addr_to_offset(addr));
102 }
103
104 #ifndef PRODUCT
105 template<typename Fn>
106 inline void G1CMMarkStack::iterate(Fn fn) const {
107 assert_at_safepoint(true);
108
109 size_t num_chunks = 0;
110
111 TaskQueueEntryChunk* cur = _chunk_list;
112 while (cur != NULL) {
113 guarantee(num_chunks <= _chunks_in_chunk_list, "Found " SIZE_FORMAT " oop chunks which is more than there should be", num_chunks);
114
115 for (size_t i = 0; i < EntriesPerChunk; ++i) {
116 if (cur->data[i].is_null()) {
117 break;
118 }
119 fn(cur->data[i]);
120 }
121 cur = cur->next;
122 num_chunks++;
123 }
124 }
125 #endif
126
127 // It scans an object and visits its children.
128 inline void G1CMTask::scan_task_entry(G1TaskQueueEntry task_entry) { process_grey_task_entry<true>(task_entry); }
129
130 inline void G1CMTask::push(G1TaskQueueEntry task_entry) {
131 assert(task_entry.is_array_slice() || _g1h->is_in_g1_reserved(task_entry.obj()), "invariant");
132 assert(task_entry.is_array_slice() || !_g1h->is_on_master_free_list(
133 _g1h->heap_region_containing(task_entry.obj())), "invariant");
134 assert(task_entry.is_array_slice() || !_g1h->is_obj_ill(task_entry.obj()), "invariant"); // FIXME!!!
135 assert(task_entry.is_array_slice() || _nextMarkBitMap->is_marked((HeapWord*)task_entry.obj()), "invariant");
136
137 if (!_task_queue->push(task_entry)) {
138 // The local task queue looks full. We need to push some entries
139 // to the global stack.
140 move_entries_to_global_stack();
141
142 // this should succeed since, even if we overflow the global
143 // stack, we should have definitely removed some entries from the
144 // local queue. So, there must be space on it.
145 bool success = _task_queue->push(task_entry);
146 assert(success, "invariant");
147 }
148 }
149
150 inline bool G1CMTask::is_below_finger(oop obj, HeapWord* global_finger) const {
151 // If obj is above the global finger, then the mark bitmap scan
152 // will find it later, and no push is needed. Similarly, if we have
153 // a current region and obj is between the local finger and the
154 // end of the current region, then no push is needed. The tradeoff
155 // of checking both vs only checking the global finger is that the
156 // local check will be more accurate and so result in fewer pushes,
157 // but may also be a little slower.
158 HeapWord* objAddr = (HeapWord*)obj;
159 if (_finger != NULL) {
160 // We have a current region.
161
162 // Finger and region values are all NULL or all non-NULL. We
163 // use _finger to check since we immediately use its value.
164 assert(_curr_region != NULL, "invariant");
165 assert(_region_limit != NULL, "invariant");
166 assert(_region_limit <= global_finger, "invariant");
167
168 // True if obj is less than the local finger, or is between
169 // the region limit and the global finger.
170 if (objAddr < _finger) {
171 return true;
172 } else if (objAddr < _region_limit) {
173 return false;
174 } // Else check global finger.
175 }
176 // Check global finger.
177 return objAddr < global_finger;
178 }
179
180 template<bool scan>
181 inline void G1CMTask::process_grey_task_entry(G1TaskQueueEntry task_entry) {
182 assert(scan || (task_entry.is_oop() && task_entry.obj()->is_typeArray()), "Skipping scan of grey non-typeArray");
183 assert(task_entry.is_array_slice() || _nextMarkBitMap->is_marked((HeapWord*)task_entry.obj()),
184 "Any stolen object should be a slice or marked");
185
186 if (scan) {
187 if (task_entry.is_array_slice()) {
188 _words_scanned += _objArray_processor.process_slice(task_entry.slice());
189 } else {
190 oop obj = task_entry.obj();
191 if (G1CMObjArrayProcessor::should_be_sliced(obj)) {
192 _words_scanned += _objArray_processor.process_obj(obj);
193 } else {
194 _words_scanned += obj->oop_iterate_size(_cm_oop_closure);;
195 }
196 }
197 }
198 check_limits();
199 }
200
201 inline size_t G1CMTask::scan_objArray(objArrayOop obj, MemRegion mr) {
202 obj->oop_iterate(_cm_oop_closure, mr);
203 return mr.word_size();
204 }
205
206 inline void G1CMTask::make_reference_grey(oop obj) {
207 if (_cm->par_mark(obj)) {
208 // No OrderAccess:store_load() is needed. It is implicit in the
209 // CAS done in G1CMBitMap::parMark() call in the routine above.
210 HeapWord* global_finger = _cm->finger();
211
212 // We only need to push a newly grey object on the mark
213 // stack if it is in a section of memory the mark bitmap
214 // scan has already examined. Mark bitmap scanning
215 // maintains progress "fingers" for determining that.
216 //
217 // Notice that the global finger might be moving forward
218 // concurrently. This is not a problem. In the worst case, we
219 // mark the object while it is above the global finger and, by
220 // the time we read the global finger, it has moved forward
221 // past this object. In this case, the object will probably
222 // be visited when a task is scanning the region and will also
223 // be pushed on the stack. So, some duplicate work, but no
224 // correctness problems.
225 if (is_below_finger(obj, global_finger)) {
226 G1TaskQueueEntry entry = G1TaskQueueEntry::from_oop(obj);
227 if (obj->is_typeArray()) {
228 // Immediately process arrays of primitive types, rather
229 // than pushing on the mark stack. This keeps us from
230 // adding humongous objects to the mark stack that might
231 // be reclaimed before the entry is processed - see
232 // selection of candidates for eager reclaim of humongous
233 // objects. The cost of the additional type test is
234 // mitigated by avoiding a trip through the mark stack,
235 // by only doing a bookkeeping update and avoiding the
236 // actual scan of the object - a typeArray contains no
237 // references, and the metadata is built-in.
238 process_grey_task_entry<false>(entry);
239 } else {
240 push(entry);
241 }
242 }
243 }
244 }
245
246 inline void G1CMTask::deal_with_reference(oop obj) {
247 increment_refs_reached();
248
249 HeapWord* objAddr = (HeapWord*) obj;
250 assert(obj->is_oop_or_null(true /* ignore mark word */), "Expected an oop or NULL at " PTR_FORMAT, p2i(obj));
251 if (_g1h->is_in_g1_reserved(objAddr)) {
252 assert(obj != NULL, "null check is implicit");
253 if (!_nextMarkBitMap->is_marked(objAddr)) {
254 // Only get the containing region if the object is not marked on the
255 // bitmap (otherwise, it's a waste of time since we won't do
256 // anything with it).
257 HeapRegion* hr = _g1h->heap_region_containing(obj);
258 if (!hr->obj_allocated_since_next_marking(obj)) {
259 make_reference_grey(obj);
260 }
261 }
262 }
263 }
264
265 inline void G1ConcurrentMark::markPrev(oop p) {
266 assert(!_prevMarkBitMap->is_marked((HeapWord*) p), "sanity");
267 _prevMarkBitMap->mark((HeapWord*) p);
268 }
269
270 bool G1ConcurrentMark::isPrevMarked(oop p) const {
271 assert(p != NULL && p->is_oop(), "expected an oop");
272 return _prevMarkBitMap->is_marked((HeapWord*)p);
273 }
274
275 inline void G1ConcurrentMark::grayRoot(oop obj, HeapRegion* hr) {
276 assert(obj != NULL, "pre-condition");
277 HeapWord* addr = (HeapWord*) obj;
278 if (hr == NULL) {
279 hr = _g1h->heap_region_containing(addr);
280 } else {
281 assert(hr->is_in(addr), "pre-condition");
282 }
283 assert(hr != NULL, "sanity");
284 // Given that we're looking for a region that contains an object
285 // header it's impossible to get back a HC region.
286 assert(!hr->is_continues_humongous(), "sanity");
287
288 if (addr < hr->next_top_at_mark_start()) {
289 if (!_nextMarkBitMap->is_marked(addr)) {
290 par_mark(obj);
291 }
292 }
293 }
294
295 inline bool G1ConcurrentMark::do_yield_check() {
296 if (SuspendibleThreadSet::should_yield()) {
297 SuspendibleThreadSet::yield();
298 return true;
299 } else {
300 return false;
301 }
302 }
303
304 #endif // SHARE_VM_GC_G1_G1CONCURRENTMARK_INLINE_HPP