1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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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).
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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/g1ConcurrentMarkBitMap.inline.hpp"
31 #include "gc/g1/g1ConcurrentMarkObjArrayProcessor.inline.hpp"
32 #include "gc/g1/g1Policy.hpp"
33 #include "gc/g1/g1RegionMarkStatsCache.inline.hpp"
34 #include "gc/g1/g1RemSetTrackingPolicy.hpp"
35 #include "gc/g1/heapRegionRemSet.hpp"
36 #include "gc/g1/heapRegion.hpp"
37 #include "gc/shared/suspendibleThreadSet.hpp"
38 #include "gc/shared/taskqueue.inline.hpp"
39 #include "utilities/bitMap.inline.hpp"
40
41 inline bool G1ConcurrentMark::mark_in_next_bitmap(uint const worker_id, oop const obj, size_t const obj_size) {
42 HeapRegion* const hr = _g1h->heap_region_containing(obj);
43 return mark_in_next_bitmap(worker_id, hr, obj, obj_size);
44 }
45
46 inline bool G1ConcurrentMark::mark_in_next_bitmap(uint const worker_id, HeapRegion* const hr, oop const obj, size_t const obj_size) {
47 assert(hr != NULL, "just checking");
48 assert(hr->is_in_reserved(obj), "Attempting to mark object at " PTR_FORMAT " that is not contained in the given region %u", p2i(obj), hr->hrm_index());
49
50 if (hr->obj_allocated_since_next_marking(obj)) {
51 return false;
52 }
53
54 // Some callers may have stale objects to mark above nTAMS after humongous reclaim.
55 // Can't assert that this is a valid object at this point, since it might be in the process of being copied by another thread.
56 assert(!hr->is_continues_humongous(), "Should not try to mark object " PTR_FORMAT " in Humongous continues region %u above nTAMS " PTR_FORMAT, p2i(obj), hr->hrm_index(), p2i(hr->next_top_at_mark_start()));
57
58 HeapWord* const obj_addr = (HeapWord*)obj;
59
60 bool success = _next_mark_bitmap->par_mark(obj_addr);
61 if (success) {
62 add_to_liveness(worker_id, obj, obj_size == 0 ? obj->size() : obj_size);
63 }
64 return success;
65 }
66
67 #ifndef PRODUCT
68 template<typename Fn>
69 inline void G1CMMarkStack::iterate(Fn fn) const {
70 assert_at_safepoint_on_vm_thread();
71
72 size_t num_chunks = 0;
73
74 TaskQueueEntryChunk* cur = _chunk_list;
75 while (cur != NULL) {
76 guarantee(num_chunks <= _chunks_in_chunk_list, "Found " SIZE_FORMAT " oop chunks which is more than there should be", num_chunks);
77
78 for (size_t i = 0; i < EntriesPerChunk; ++i) {
79 if (cur->data[i].is_null()) {
80 break;
81 }
82 fn(cur->data[i]);
83 }
84 cur = cur->next;
85 num_chunks++;
86 }
87 }
88 #endif
89
90 // It scans an object and visits its children.
91 inline void G1CMTask::scan_task_entry(G1TaskQueueEntry task_entry) { process_grey_task_entry<true>(task_entry); }
92
93 inline void G1CMTask::push(G1TaskQueueEntry task_entry) {
94 assert(task_entry.is_array_slice() || _g1h->is_in_g1_reserved(task_entry.obj()), "invariant");
95 assert(task_entry.is_array_slice() || !_g1h->is_on_master_free_list(
96 _g1h->heap_region_containing(task_entry.obj())), "invariant");
97 assert(task_entry.is_array_slice() || !_g1h->is_obj_ill(task_entry.obj()), "invariant"); // FIXME!!!
98 assert(task_entry.is_array_slice() || _next_mark_bitmap->is_marked((HeapWord*)task_entry.obj()), "invariant");
99
100 if (!_task_queue->push(task_entry)) {
101 // The local task queue looks full. We need to push some entries
102 // to the global stack.
103 move_entries_to_global_stack();
104
105 // this should succeed since, even if we overflow the global
106 // stack, we should have definitely removed some entries from the
107 // local queue. So, there must be space on it.
108 bool success = _task_queue->push(task_entry);
109 assert(success, "invariant");
110 }
111 }
112
113 inline bool G1CMTask::is_below_finger(oop obj, HeapWord* global_finger) const {
114 // If obj is above the global finger, then the mark bitmap scan
115 // will find it later, and no push is needed. Similarly, if we have
116 // a current region and obj is between the local finger and the
117 // end of the current region, then no push is needed. The tradeoff
118 // of checking both vs only checking the global finger is that the
119 // local check will be more accurate and so result in fewer pushes,
120 // but may also be a little slower.
121 HeapWord* objAddr = (HeapWord*)obj;
122 if (_finger != NULL) {
123 // We have a current region.
124
125 // Finger and region values are all NULL or all non-NULL. We
126 // use _finger to check since we immediately use its value.
127 assert(_curr_region != NULL, "invariant");
128 assert(_region_limit != NULL, "invariant");
129 assert(_region_limit <= global_finger, "invariant");
130
131 // True if obj is less than the local finger, or is between
132 // the region limit and the global finger.
133 if (objAddr < _finger) {
134 return true;
135 } else if (objAddr < _region_limit) {
136 return false;
137 } // Else check global finger.
138 }
139 // Check global finger.
140 return objAddr < global_finger;
141 }
142
143 template<bool scan>
144 inline void G1CMTask::process_grey_task_entry(G1TaskQueueEntry task_entry) {
145 assert(scan || (task_entry.is_oop() && task_entry.obj()->is_typeArray()), "Skipping scan of grey non-typeArray");
146 assert(task_entry.is_array_slice() || _next_mark_bitmap->is_marked((HeapWord*)task_entry.obj()),
147 "Any stolen object should be a slice or marked");
148
149 if (scan) {
150 if (task_entry.is_array_slice()) {
151 _words_scanned += _objArray_processor.process_slice(task_entry.slice());
152 } else {
153 oop obj = task_entry.obj();
154 if (G1CMObjArrayProcessor::should_be_sliced(obj)) {
155 _words_scanned += _objArray_processor.process_obj(obj);
156 } else {
157 _words_scanned += obj->oop_iterate_size(_cm_oop_closure);;
158 }
159 }
160 }
161 check_limits();
162 }
163
164 inline size_t G1CMTask::scan_objArray(objArrayOop obj, MemRegion mr) {
165 obj->oop_iterate(_cm_oop_closure, mr);
166 return mr.word_size();
167 }
168
169 inline HeapWord* G1ConcurrentMark::top_at_rebuild_start(uint region) const {
170 assert(region < _g1h->max_regions(), "Tried to access TARS for region %u out of bounds", region);
171 return _top_at_rebuild_starts[region];
172 }
173
174 inline void G1ConcurrentMark::update_top_at_rebuild_start(HeapRegion* r) {
175 uint const region = r->hrm_index();
176 assert(region < _g1h->max_regions(), "Tried to access TARS for region %u out of bounds", region);
177 assert(_top_at_rebuild_starts[region] == NULL,
178 "TARS for region %u has already been set to " PTR_FORMAT " should be NULL",
179 region, p2i(_top_at_rebuild_starts[region]));
180 G1RemSetTrackingPolicy* tracker = _g1h->g1_policy()->remset_tracker();
181 if (tracker->needs_scan_for_rebuild(r)) {
182 _top_at_rebuild_starts[region] = r->top();
183 } else {
184 // Leave TARS at NULL.
185 }
186 }
187
188 inline void G1CMTask::update_liveness(oop const obj, const size_t obj_size) {
189 _mark_stats_cache.add_live_words(_g1h->addr_to_region((HeapWord*)obj), obj_size);
190 }
191
192 inline void G1ConcurrentMark::add_to_liveness(uint worker_id, oop const obj, size_t size) {
193 task(worker_id)->update_liveness(obj, size);
194 }
195
196 inline bool G1CMTask::make_reference_grey(oop obj) {
197 if (!_cm->mark_in_next_bitmap(_worker_id, obj)) {
198 return false;
199 }
200
201 // No OrderAccess:store_load() is needed. It is implicit in the
202 // CAS done in G1CMBitMap::parMark() call in the routine above.
203 HeapWord* global_finger = _cm->finger();
204
205 // We only need to push a newly grey object on the mark
206 // stack if it is in a section of memory the mark bitmap
207 // scan has already examined. Mark bitmap scanning
208 // maintains progress "fingers" for determining that.
209 //
210 // Notice that the global finger might be moving forward
211 // concurrently. This is not a problem. In the worst case, we
212 // mark the object while it is above the global finger and, by
213 // the time we read the global finger, it has moved forward
214 // past this object. In this case, the object will probably
215 // be visited when a task is scanning the region and will also
216 // be pushed on the stack. So, some duplicate work, but no
217 // correctness problems.
218 if (is_below_finger(obj, global_finger)) {
219 G1TaskQueueEntry entry = G1TaskQueueEntry::from_oop(obj);
220 if (obj->is_typeArray()) {
221 // Immediately process arrays of primitive types, rather
222 // than pushing on the mark stack. This keeps us from
223 // adding humongous objects to the mark stack that might
224 // be reclaimed before the entry is processed - see
225 // selection of candidates for eager reclaim of humongous
226 // objects. The cost of the additional type test is
227 // mitigated by avoiding a trip through the mark stack,
228 // by only doing a bookkeeping update and avoiding the
229 // actual scan of the object - a typeArray contains no
230 // references, and the metadata is built-in.
231 process_grey_task_entry<false>(entry);
232 } else {
233 push(entry);
234 }
235 }
236 return true;
237 }
238
239 template <class T>
240 inline bool G1CMTask::deal_with_reference(T* p) {
241 increment_refs_reached();
242 oop const obj = RawAccess<MO_VOLATILE>::oop_load(p);
243 if (obj == NULL) {
244 return false;
245 }
246 return make_reference_grey(obj);
247 }
248
249 inline void G1ConcurrentMark::mark_in_prev_bitmap(oop p) {
250 assert(!_prev_mark_bitmap->is_marked((HeapWord*) p), "sanity");
251 _prev_mark_bitmap->mark((HeapWord*) p);
252 }
253
254 bool G1ConcurrentMark::is_marked_in_prev_bitmap(oop p) const {
255 assert(p != NULL && oopDesc::is_oop(p), "expected an oop");
256 return _prev_mark_bitmap->is_marked((HeapWord*)p);
257 }
258
259 bool G1ConcurrentMark::is_marked_in_next_bitmap(oop p) const {
260 assert(p != NULL && oopDesc::is_oop(p), "expected an oop");
261 return _next_mark_bitmap->is_marked((HeapWord*)p);
262 }
263
264 inline bool G1ConcurrentMark::do_yield_check() {
265 if (SuspendibleThreadSet::should_yield()) {
266 SuspendibleThreadSet::yield();
267 return true;
268 } else {
269 return false;
270 }
271 }
272
273 #endif // SHARE_VM_GC_G1_G1CONCURRENTMARK_INLINE_HPP