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24
25 #ifndef SHARE_GC_G1_G1CONCURRENTMARK_INLINE_HPP
26 #define SHARE_GC_G1_G1CONCURRENTMARK_INLINE_HPP
27
28 #include "gc/g1/g1ConcurrentMark.hpp"
29
30 #include "gc/g1/g1CollectedHeap.inline.hpp"
31 #include "gc/g1/g1CollectorState.inline.hpp"
32 #include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"
33 #include "gc/g1/g1HeapRegion.hpp"
34 #include "gc/g1/g1HeapRegionRemSet.inline.hpp"
35 #include "gc/g1/g1OopClosures.inline.hpp"
36 #include "gc/g1/g1Policy.hpp"
37 #include "gc/g1/g1RegionMarkStatsCache.inline.hpp"
38 #include "gc/g1/g1RemSetTrackingPolicy.hpp"
39 #include "gc/shared/suspendibleThreadSet.hpp"
40 #include "gc/shared/taskqueue.inline.hpp"
41 #include "utilities/bitMap.inline.hpp"
42 #include "utilities/checkedCast.hpp"
43
44 inline bool G1CMIsAliveClosure::do_object_b(oop obj) {
45 // Check whether the passed in object is null. During discovery the referent
46 // may be cleared between the initial check and being passed in here.
47 if (obj == nullptr) {
48 // Return true to avoid discovery when the referent is null.
49 return true;
50 }
51
52 // All objects allocated since the start of marking are considered live.
53 if (_cm->obj_allocated_since_mark_start(obj)) {
54 return true;
55 }
56
57 // All objects that are marked are live.
58 return _cm->is_marked_in_bitmap(obj);
59 }
60
61 inline bool G1CMSubjectToDiscoveryClosure::do_object_b(oop obj) {
62 assert(obj != nullptr, "precondition");
63 assert(_g1h->is_in_reserved(obj), "Trying to discover obj " PTR_FORMAT " not in heap", p2i(obj));
64
65 return _g1h->heap_region_containing(obj)->is_old_or_humongous();
66 }
67
68 inline bool G1ConcurrentMark::mark_in_bitmap(uint const worker_id, oop const obj) {
69 if (obj_allocated_since_mark_start(obj)) {
70 return false;
71 }
72
73 // Some callers may have stale objects to mark above TAMS after humongous reclaim.
74 // 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.
75 DEBUG_ONLY(G1HeapRegion* const hr = _g1h->heap_region_containing(obj);)
76 assert(!hr->is_continues_humongous(),
77 "Should not try to mark object " PTR_FORMAT " in Humongous continues region %u above TAMS " PTR_FORMAT,
78 p2i(obj), hr->hrm_index(), p2i(top_at_mark_start(hr)));
79
80 bool success = _mark_bitmap.par_mark(obj);
81 if (success) {
82 add_to_liveness(worker_id, obj, obj->size());
83 }
84 return success;
85 }
86
87 #ifndef PRODUCT
88 template<typename Fn>
89 inline void G1CMMarkStack::iterate(Fn fn) const {
90 assert_at_safepoint_on_vm_thread();
91
92 size_t num_chunks = 0;
93
94 TaskQueueEntryChunk* cur = _chunk_list.load_relaxed();
95 while (cur != nullptr) {
96 guarantee(num_chunks <= _chunks_in_chunk_list, "Found %zu oop chunks which is more than there should be", num_chunks);
97
98 for (size_t i = 0; i < EntriesPerChunk; ++i) {
99 if (cur->data[i].is_null()) {
100 break;
101 }
102 fn(cur->data[i]);
103 }
104 cur = cur->next;
105 num_chunks++;
106 }
107 }
108 #endif
109
110 inline void G1CMTask::process_klass(Klass* klass) {
111 _cm_oop_closure->do_klass(klass);
112 }
113
114 // It scans an object and visits its children.
115 inline void G1CMTask::process_entry(G1TaskQueueEntry task_entry, bool stolen) {
116 assert(task_entry.is_partial_array_state() || _mark_bitmap->is_marked(cast_from_oop<HeapWord*>(task_entry.to_oop())),
117 "Any stolen object should be a slice or marked");
118
119 if (task_entry.is_partial_array_state()) {
120 _words_scanned += process_partial_array(task_entry, stolen);
121 } else {
122 oop obj = task_entry.to_oop();
123 if (should_be_sliced(obj)) {
124 _words_scanned += start_partial_array_processing(objArrayOop(obj));
125 } else {
126 _words_scanned += obj->oop_iterate_size(_cm_oop_closure);
127 }
128 }
129
130 check_limits();
131 }
132
133 inline void G1CMTask::push(G1TaskQueueEntry task_entry) {
134 assert(task_entry.is_partial_array_state() || _g1h->is_in_reserved(task_entry.to_oop()), "invariant");
135 assert(task_entry.is_partial_array_state() || !_g1h->is_on_master_free_list(
136 _g1h->heap_region_containing(task_entry.to_oop())), "invariant");
137 assert(task_entry.is_partial_array_state() || _mark_bitmap->is_marked(cast_from_oop<HeapWord*>(task_entry.to_oop())), "invariant");
138
139 if (!_task_queue->push(task_entry)) {
140 // The local task queue looks full. We need to push some entries
141 // to the global stack.
142 move_entries_to_global_stack();
143
144 // this should succeed since, even if we overflow the global
145 // stack, we should have definitely removed some entries from the
146 // local queue. So, there must be space on it.
147 bool success = _task_queue->push(task_entry);
148 assert(success, "invariant");
149 }
150 }
151
152 inline bool G1CMTask::is_below_finger(oop obj, HeapWord* global_finger) const {
153 // If obj is above the global finger, then the mark bitmap scan
154 // will find it later, and no push is needed. Similarly, if we have
155 // a current region and obj is between the local finger and the
156 // end of the current region, then no push is needed. The tradeoff
157 // of checking both vs only checking the global finger is that the
158 // local check will be more accurate and so result in fewer pushes,
159 // but may also be a little slower.
160 HeapWord* objAddr = cast_from_oop<HeapWord*>(obj);
161 if (_finger != nullptr) {
162 // We have a current region.
163
164 // Finger and region values are all null or all non-null. We
165 // use _finger to check since we immediately use its value.
166 assert(_curr_region != nullptr, "invariant");
167 assert(_region_limit != nullptr, "invariant");
168 assert(_region_limit <= global_finger, "invariant");
169
170 // True if obj is less than the local finger, or is between
171 // the region limit and the global finger.
172 if (objAddr < _finger) {
173 return true;
174 } else if (objAddr < _region_limit) {
175 return false;
176 } // Else check global finger.
177 }
178 // Check global finger.
179 return objAddr < global_finger;
180 }
181
182 inline bool G1CMTask::should_be_sliced(oop obj) {
183 return obj->is_array_with_oops() && ((objArrayOop)obj)->length() >= (int)ObjArrayMarkingStride;
184 }
185
186 inline void G1CMTask::process_array_chunk(objArrayOop obj, size_t start, size_t end) {
187 precond(obj->is_array_with_oops());
188 obj->oop_iterate_elements_range(_cm_oop_closure,
189 checked_cast<int>(start),
190 checked_cast<int>(end));
191 }
192
193 inline void G1ConcurrentMark::update_top_at_mark_start(G1HeapRegion* r) {
194 assert_fully_initialized();
195 assert(_g1h->collector_state()->is_in_concurrent_start_gc(), "must be");
196 uint const region = r->hrm_index();
197 assert(region < _g1h->max_num_regions(), "Tried to access TAMS for region %u out of bounds", region);
198 _top_at_mark_starts[region].store_relaxed(r->top());
199 }
200
201 inline void G1ConcurrentMark::set_top_at_mark_start_to_bottom(G1HeapRegion* r) {
202 assert_fully_initialized();
203 _top_at_mark_starts[r->hrm_index()].store_relaxed(r->bottom());
204 }
205
206 inline void G1ConcurrentMark::assert_top_at_mark_start_is_bottom(G1HeapRegion* r) {
207 // Can not assert anything if not initialized.
208 if (!tams_may_be_read()) {
209 return;
210 }
211 HeapWord* local_top_at_mark_start = top_at_mark_start(r);
212 assert(local_top_at_mark_start == r->bottom(),
213 "must be, but tams for r %u (%s) is" PTR_FORMAT,
214 r->hrm_index(), r->get_short_type_str(), p2i(local_top_at_mark_start));
215 }
216
217 inline HeapWord* G1ConcurrentMark::top_at_mark_start_or_bottom(const G1HeapRegion* r) const {
218 if (!tams_may_be_read()) {
219 return r->bottom();
220 }
221 return top_at_mark_start(r);
222 }
223
224 inline HeapWord* G1ConcurrentMark::top_at_mark_start_for_verification(const G1HeapRegion* r,
225 bool concurrent_cycle_aborted) const {
226 if (!is_fully_initialized()) {
227 // We do not have TAMS data yet.
228 return r->bottom();
229 }
230 if (tams_may_be_read()) {
231 // Normal case, we can read TAMS data and it is valid.
232 return top_at_mark_start(r);
233 }
234 if (concurrent_cycle_aborted) {
235 assert(_g1h->collector_state()->is_in_full_gc(), "Must be in Full GC if concurrent cycle has aborted");
236 assert(r->hrm_index() < _g1h->max_num_regions(),
237 "Tried to access TAMS for region %u out of bounds", r->hrm_index());
238 return _top_at_mark_starts[r->hrm_index()].load_relaxed();
239 }
240 return r->bottom();
241 }
242
243 inline bool G1ConcurrentMark::tams_may_be_read() const {
244 // We need the TAMS to be valid even outside of actual marking for e.g. clearing the bitmap.
245 G1CollectorState* state = _g1h->collector_state();
246 return is_fully_initialized() &&
247 (state->is_in_concurrent_cycle() || state->is_in_concurrent_start_gc());
248 }
249
250 inline HeapWord* G1ConcurrentMark::top_at_mark_start(const G1HeapRegion* r) const {
251 return top_at_mark_start(r->hrm_index());
252 }
253
254 inline HeapWord* G1ConcurrentMark::top_at_mark_start(uint region) const {
255 assert_fully_initialized();
256 assert(tams_may_be_read(), "must be");
257 assert(region < _g1h->max_num_regions(), "Tried to access TARS for region %u out of bounds", region);
258 return _top_at_mark_starts[region].load_relaxed();
259 }
260
261 inline bool G1ConcurrentMark::obj_allocated_since_mark_start(oop obj) const {
262 uint const region = _g1h->addr_to_region(obj);
263 assert(region < _g1h->max_num_regions(), "obj " PTR_FORMAT " outside heap %u", p2i(obj), region);
264 return cast_from_oop<HeapWord*>(obj) >= top_at_mark_start(region);
265 }
266
267 inline HeapWord* G1ConcurrentMark::top_at_rebuild_start(G1HeapRegion* r) const {
268 assert_fully_initialized();
269 return _top_at_rebuild_starts[r->hrm_index()].load_relaxed();
270 }
271
272 inline void G1ConcurrentMark::update_top_at_rebuild_start(G1HeapRegion* r) {
273 assert_fully_initialized();
274 assert(r->is_old() || r->is_humongous(), "precondition");
275
276 uint const region = r->hrm_index();
277 assert(region < _g1h->max_num_regions(), "Tried to access TARS for region %u out of bounds", region);
278 assert(top_at_rebuild_start(r) == nullptr,
279 "TARS for region %u has already been set to " PTR_FORMAT " should be null",
280 region, p2i(top_at_rebuild_start(r)));
281 _top_at_rebuild_starts[region].store_relaxed(r->top());
282 }
283
284 inline void G1CMTask::update_liveness(oop const obj, const size_t obj_size) {
285 _mark_stats_cache.add_live_words(_g1h->addr_to_region(obj), obj_size);
286 }
287
288 inline void G1CMTask::inc_incoming_refs(oop const obj) {
289 _mark_stats_cache.inc_incoming_refs(_g1h->addr_to_region(obj));
290 }
291
292 inline void G1ConcurrentMark::add_to_liveness(uint worker_id, oop const obj, size_t size) {
293 task(worker_id)->update_liveness(obj, size);
294 }
295
296 inline bool G1ConcurrentMark::contains_live_object(uint region) const {
297 assert_fully_initialized();
298 return _region_mark_stats[region].live_words() != 0;
299 }
300
301 inline size_t G1ConcurrentMark::live_bytes(uint region) const {
302 assert_fully_initialized();
303 return _region_mark_stats[region].live_words() * HeapWordSize;
304 }
305
306 inline void G1ConcurrentMark::set_live_bytes(uint region, size_t live_bytes) {
307 assert_fully_initialized();
308 _region_mark_stats[region]._live_words.store_relaxed(live_bytes / HeapWordSize);
309 }
310
311 inline size_t G1ConcurrentMark::incoming_refs(uint region) const {
312 assert_fully_initialized();
313 return _region_mark_stats[region].incoming_refs();
314 }
315
316 inline void G1CMTask::abort_marking_if_regular_check_fail() {
317 if (!regular_clock_call()) {
318 set_has_aborted();
319 }
320 }
321
322 inline bool G1CMTask::make_reference_grey(oop obj) {
323 if (!_cm->mark_in_bitmap(_worker_id, obj)) {
324 return false;
325 }
326
327 // No OrderAccess:store_load() is needed. It is implicit in the
328 // CAS done in G1CMBitMap::parMark() call in the routine above.
329 HeapWord* global_finger = _cm->finger();
330
331 // We only need to push a newly grey object on the mark
332 // stack if it is in a section of memory the mark bitmap
333 // scan has already examined. Mark bitmap scanning
334 // maintains progress "fingers" for determining that.
335 //
336 // Notice that the global finger might be moving forward
337 // concurrently. This is not a problem. In the worst case, we
338 // mark the object while it is above the global finger and, by
339 // the time we read the global finger, it has moved forward
340 // past this object. In this case, the object will probably
341 // be visited when a task is scanning the region and will also
342 // be pushed on the stack. So, some duplicate work, but no
343 // correctness problems.
344 if (is_below_finger(obj, global_finger)) {
345 if (_g1h->can_be_marked_through_immediately(obj)) {
346 // Immediately process arrays of types without oops, rather
347 // than pushing on the mark stack. This keeps us from
348 // adding humongous objects to the mark stack that might
349 // be reclaimed before the entry is processed - see
350 // selection of candidates for eager reclaim of humongous
351 // objects. The cost of the additional type test is
352 // mitigated by avoiding a trip through the mark stack,
353 // by only doing a bookkeeping update and avoiding the
354 // actual scan of the object - the object contains no
355 // references (but the metadata must be processed).
356 process_klass(obj->klass());
357 } else {
358 G1TaskQueueEntry entry(obj);
359 push(entry);
360 }
361 }
362 return true;
363 }
364
365 template <class T>
366 inline bool G1CMTask::deal_with_reference(T* p) {
367 increment_refs_reached();
368 oop const obj = RawAccess<MO_RELAXED>::oop_load(p);
369 if (obj == nullptr) {
370 return false;
371 }
372
373 if (!G1HeapRegion::is_in_same_region(p, obj)) {
374 inc_incoming_refs(obj);
375 }
376 return make_reference_grey(obj);
377 }
378
379 inline void G1ConcurrentMark::raw_mark_in_bitmap(oop obj) {
380 _mark_bitmap.par_mark(obj);
381 }
382
383 bool G1ConcurrentMark::is_marked_in_bitmap(oop p) const {
384 assert(p != nullptr && oopDesc::is_oop(p), "expected an oop");
385 return _mark_bitmap.is_marked(cast_from_oop<HeapWord*>(p));
386 }
387
388 inline bool G1ConcurrentMark::do_yield_check() {
389 if (SuspendibleThreadSet::should_yield()) {
390 SuspendibleThreadSet::yield();
391 return true;
392 } else {
393 return false;
394 }
395 }
396
397 #endif // SHARE_GC_G1_G1CONCURRENTMARK_INLINE_HPP