1 /* 2 * Copyright (c) 2001, 2020, 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. 18 * 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 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_GC_G1_G1CONCURRENTMARK_INLINE_HPP 26 #define SHARE_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/g1OopClosures.inline.hpp" 33 #include "gc/g1/g1Policy.hpp" 34 #include "gc/g1/g1RegionMarkStatsCache.inline.hpp" 35 #include "gc/g1/g1RemSetTrackingPolicy.hpp" 36 #include "gc/g1/heapRegionRemSet.hpp" 37 #include "gc/g1/heapRegion.hpp" 38 #include "gc/shared/suspendibleThreadSet.hpp" 39 #include "gc/shared/taskqueue.inline.hpp" 40 #include "utilities/bitMap.inline.hpp" 41 42 inline bool G1CMIsAliveClosure::do_object_b(oop obj) { 43 return !_g1h->is_obj_ill(obj); 44 } 45 46 inline bool G1CMSubjectToDiscoveryClosure::do_object_b(oop obj) { 47 // Re-check whether the passed object is null. With ReferentBasedDiscovery the 48 // mutator may have changed the referent's value (i.e. cleared it) between the 49 // time the referent was determined to be potentially alive and calling this 50 // method. 51 if (obj == NULL) { 52 return false; 53 } 54 assert(_g1h->is_in_reserved(obj), "Trying to discover obj " PTR_FORMAT " not in heap", p2i(obj)); 55 return _g1h->heap_region_containing(obj)->is_old_or_humongous_or_archive(); 56 } 57 58 inline bool G1ConcurrentMark::mark_in_next_bitmap(uint const worker_id, oop const obj) { 59 HeapRegion* const hr = _g1h->heap_region_containing(obj); 60 return mark_in_next_bitmap(worker_id, hr, obj); 61 } 62 63 inline bool G1ConcurrentMark::mark_in_next_bitmap(uint const worker_id, HeapRegion* const hr, oop const obj) { 64 assert(hr != NULL, "just checking"); 65 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()); 66 67 if (hr->obj_allocated_since_next_marking(obj)) { 68 return false; 69 } 70 71 // Some callers may have stale objects to mark above nTAMS after humongous reclaim. 72 // 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. 73 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())); 74 75 bool success = _next_mark_bitmap->par_mark(obj); 76 if (success) { 77 add_to_liveness(worker_id, obj, obj->size()); 78 } 79 return success; 80 } 81 82 #ifndef PRODUCT 83 template<typename Fn> 84 inline void G1CMMarkStack::iterate(Fn fn) const { 85 assert_at_safepoint_on_vm_thread(); 86 87 size_t num_chunks = 0; 88 89 TaskQueueEntryChunk* cur = _chunk_list; 90 while (cur != NULL) { 91 guarantee(num_chunks <= _chunks_in_chunk_list, "Found " SIZE_FORMAT " oop chunks which is more than there should be", num_chunks); 92 93 for (size_t i = 0; i < EntriesPerChunk; ++i) { 94 if (cur->data[i].is_null()) { 95 break; 96 } 97 fn(cur->data[i]); 98 } 99 cur = cur->next; 100 num_chunks++; 101 } 102 } 103 #endif 104 105 // It scans an object and visits its children. 106 inline void G1CMTask::scan_task_entry(G1TaskQueueEntry task_entry) { process_grey_task_entry<true>(task_entry); } 107 108 inline void G1CMTask::push(G1TaskQueueEntry task_entry) { 109 assert(task_entry.is_array_slice() || _g1h->is_in_g1_reserved(task_entry.obj()), "invariant"); 110 assert(task_entry.is_array_slice() || !_g1h->is_on_master_free_list( 111 _g1h->heap_region_containing(task_entry.obj())), "invariant"); 112 assert(task_entry.is_array_slice() || !_g1h->is_obj_ill(task_entry.obj()), "invariant"); // FIXME!!! 113 assert(task_entry.is_array_slice() || _next_mark_bitmap->is_marked(cast_from_oop<HeapWord*>(task_entry.obj())), "invariant"); 114 115 if (!_task_queue->push(task_entry)) { 116 // The local task queue looks full. We need to push some entries 117 // to the global stack. 118 move_entries_to_global_stack(); 119 120 // this should succeed since, even if we overflow the global 121 // stack, we should have definitely removed some entries from the 122 // local queue. So, there must be space on it. 123 bool success = _task_queue->push(task_entry); 124 assert(success, "invariant"); 125 } 126 } 127 128 inline bool G1CMTask::is_below_finger(oop obj, HeapWord* global_finger) const { 129 // If obj is above the global finger, then the mark bitmap scan 130 // will find it later, and no push is needed. Similarly, if we have 131 // a current region and obj is between the local finger and the 132 // end of the current region, then no push is needed. The tradeoff 133 // of checking both vs only checking the global finger is that the 134 // local check will be more accurate and so result in fewer pushes, 135 // but may also be a little slower. 136 HeapWord* objAddr = cast_from_oop<HeapWord*>(obj); 137 if (_finger != NULL) { 138 // We have a current region. 139 140 // Finger and region values are all NULL or all non-NULL. We 141 // use _finger to check since we immediately use its value. 142 assert(_curr_region != NULL, "invariant"); 143 assert(_region_limit != NULL, "invariant"); 144 assert(_region_limit <= global_finger, "invariant"); 145 146 // True if obj is less than the local finger, or is between 147 // the region limit and the global finger. 148 if (objAddr < _finger) { 149 return true; 150 } else if (objAddr < _region_limit) { 151 return false; 152 } // Else check global finger. 153 } 154 // Check global finger. 155 return objAddr < global_finger; 156 } 157 158 template<bool scan> 159 inline void G1CMTask::process_grey_task_entry(G1TaskQueueEntry task_entry) { 160 assert(scan || (task_entry.is_oop() && task_entry.obj()->is_typeArray()), "Skipping scan of grey non-typeArray"); 161 assert(task_entry.is_array_slice() || _next_mark_bitmap->is_marked(cast_from_oop<HeapWord*>(task_entry.obj())), 162 "Any stolen object should be a slice or marked"); 163 164 if (scan) { 165 if (task_entry.is_array_slice()) { 166 _words_scanned += _objArray_processor.process_slice(task_entry.slice()); 167 } else { 168 oop obj = task_entry.obj(); 169 if (G1CMObjArrayProcessor::should_be_sliced(obj)) { 170 _words_scanned += _objArray_processor.process_obj(obj); 171 } else { 172 _words_scanned += obj->oop_iterate_size(_cm_oop_closure);; 173 } 174 } 175 } 176 check_limits(); 177 } 178 179 inline size_t G1CMTask::scan_objArray(objArrayOop obj, MemRegion mr) { 180 obj->oop_iterate(_cm_oop_closure, mr); 181 return mr.word_size(); 182 } 183 184 inline HeapWord* G1ConcurrentMark::top_at_rebuild_start(uint region) const { 185 assert(region < _g1h->max_regions(), "Tried to access TARS for region %u out of bounds", region); 186 return _top_at_rebuild_starts[region]; 187 } 188 189 inline void G1ConcurrentMark::update_top_at_rebuild_start(HeapRegion* r) { 190 uint const region = r->hrm_index(); 191 assert(region < _g1h->max_regions(), "Tried to access TARS for region %u out of bounds", region); 192 assert(_top_at_rebuild_starts[region] == NULL, 193 "TARS for region %u has already been set to " PTR_FORMAT " should be NULL", 194 region, p2i(_top_at_rebuild_starts[region])); 195 G1RemSetTrackingPolicy* tracker = _g1h->policy()->remset_tracker(); 196 if (tracker->needs_scan_for_rebuild(r)) { 197 _top_at_rebuild_starts[region] = r->top(); 198 } else { 199 // Leave TARS at NULL. 200 } 201 } 202 203 inline void G1CMTask::update_liveness(oop const obj, const size_t obj_size) { 204 _mark_stats_cache.add_live_words(_g1h->addr_to_region(cast_from_oop<HeapWord*>(obj)), obj_size); 205 } 206 207 inline void G1ConcurrentMark::add_to_liveness(uint worker_id, oop const obj, size_t size) { 208 task(worker_id)->update_liveness(obj, size); 209 } 210 211 inline void G1CMTask::abort_marking_if_regular_check_fail() { 212 if (!regular_clock_call()) { 213 set_has_aborted(); 214 } 215 } 216 217 inline bool G1CMTask::make_reference_grey(oop obj) { 218 if (!_cm->mark_in_next_bitmap(_worker_id, obj)) { 219 return false; 220 } 221 222 // No OrderAccess:store_load() is needed. It is implicit in the 223 // CAS done in G1CMBitMap::parMark() call in the routine above. 224 HeapWord* global_finger = _cm->finger(); 225 226 // We only need to push a newly grey object on the mark 227 // stack if it is in a section of memory the mark bitmap 228 // scan has already examined. Mark bitmap scanning 229 // maintains progress "fingers" for determining that. 230 // 231 // Notice that the global finger might be moving forward 232 // concurrently. This is not a problem. In the worst case, we 233 // mark the object while it is above the global finger and, by 234 // the time we read the global finger, it has moved forward 235 // past this object. In this case, the object will probably 236 // be visited when a task is scanning the region and will also 237 // be pushed on the stack. So, some duplicate work, but no 238 // correctness problems. 239 if (is_below_finger(obj, global_finger)) { 240 G1TaskQueueEntry entry = G1TaskQueueEntry::from_oop(obj); 241 if (obj->is_typeArray()) { 242 // Immediately process arrays of primitive types, rather 243 // than pushing on the mark stack. This keeps us from 244 // adding humongous objects to the mark stack that might 245 // be reclaimed before the entry is processed - see 246 // selection of candidates for eager reclaim of humongous 247 // objects. The cost of the additional type test is 248 // mitigated by avoiding a trip through the mark stack, 249 // by only doing a bookkeeping update and avoiding the 250 // actual scan of the object - a typeArray contains no 251 // references, and the metadata is built-in. 252 process_grey_task_entry<false>(entry); 253 } else { 254 push(entry); 255 } 256 } 257 return true; 258 } 259 260 template <class T> 261 inline bool G1CMTask::deal_with_reference(T* p) { 262 increment_refs_reached(); 263 oop const obj = RawAccess<MO_RELAXED>::oop_load(p); 264 if (obj == NULL) { 265 return false; 266 } 267 return make_reference_grey(obj); 268 } 269 270 inline void G1ConcurrentMark::mark_in_prev_bitmap(oop p) { 271 assert(!_prev_mark_bitmap->is_marked(p), "sanity"); 272 _prev_mark_bitmap->mark(p); 273 } 274 275 bool G1ConcurrentMark::is_marked_in_prev_bitmap(oop p) const { 276 assert(p != NULL && oopDesc::is_oop(p), "expected an oop"); 277 return _prev_mark_bitmap->is_marked(cast_from_oop<HeapWord*>(p)); 278 } 279 280 bool G1ConcurrentMark::is_marked_in_next_bitmap(oop p) const { 281 assert(p != NULL && oopDesc::is_oop(p), "expected an oop"); 282 return _next_mark_bitmap->is_marked(cast_from_oop<HeapWord*>(p)); 283 } 284 285 inline bool G1ConcurrentMark::do_yield_check() { 286 if (SuspendibleThreadSet::should_yield()) { 287 SuspendibleThreadSet::yield(); 288 return true; 289 } else { 290 return false; 291 } 292 } 293 294 #endif // SHARE_GC_G1_G1CONCURRENTMARK_INLINE_HPP