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. 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_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->parMark((HeapWord*)obj); 37 } 38 39 inline bool G1CMBitMapRO::iterate(BitMapClosure* cl, MemRegion mr) { 40 HeapWord* start_addr = MAX2(startWord(), mr.start()); 41 HeapWord* end_addr = MIN2(endWord(), mr.end()); 42 43 if (end_addr > start_addr) { 44 // Right-open interval [start-offset, end-offset). 45 BitMap::idx_t start_offset = heapWordToOffset(start_addr); 46 BitMap::idx_t end_offset = heapWordToOffset(end_addr); 47 48 start_offset = _bm.get_next_one_offset(start_offset, end_offset); 49 while (start_offset < end_offset) { 50 if (!cl->do_bit(start_offset)) { 51 return false; 52 } 53 HeapWord* next_addr = MIN2(nextObject(offsetToHeapWord(start_offset)), end_addr); 54 BitMap::idx_t next_offset = heapWordToOffset(next_addr); 55 start_offset = _bm.get_next_one_offset(next_offset, end_offset); 56 } 57 } 58 return true; 59 } 60 61 // The argument addr should be the start address of a valid object 62 HeapWord* G1CMBitMapRO::nextObject(HeapWord* addr) { 63 oop obj = (oop) addr; 64 HeapWord* res = addr + obj->size(); 65 assert(offsetToHeapWord(heapWordToOffset(res)) == res, "sanity"); 66 return res; 67 } 68 69 #define check_mark(addr) \ 70 assert(_bmStartWord <= (addr) && (addr) < (_bmStartWord + _bmWordSize), \ 71 "outside underlying space?"); \ 72 assert(G1CollectedHeap::heap()->is_in_exact(addr), \ 73 "Trying to access not available bitmap " PTR_FORMAT \ 74 " corresponding to " PTR_FORMAT " (%u)", \ 75 p2i(this), p2i(addr), G1CollectedHeap::heap()->addr_to_region(addr)); 76 77 inline void G1CMBitMap::mark(HeapWord* addr) { 78 check_mark(addr); 79 _bm.set_bit(heapWordToOffset(addr)); 80 } 81 82 inline void G1CMBitMap::clear(HeapWord* addr) { 83 check_mark(addr); 84 _bm.clear_bit(heapWordToOffset(addr)); 85 } 86 87 inline bool G1CMBitMap::parMark(HeapWord* addr) { 88 check_mark(addr); 89 return _bm.par_set_bit(heapWordToOffset(addr)); 90 } 91 92 #undef check_mark 93 94 #ifndef PRODUCT 95 template<typename Fn> 96 inline void G1CMMarkStack::iterate(Fn fn) const { 97 assert_at_safepoint(true); 98 99 size_t num_chunks = 0; 100 101 TaskQueueEntryChunk* cur = _chunk_list; 102 while (cur != NULL) { 103 guarantee(num_chunks <= _chunks_in_chunk_list, "Found " SIZE_FORMAT " oop chunks which is more than there should be", num_chunks); 104 105 for (size_t i = 0; i < EntriesPerChunk; ++i) { 106 if (cur->data[i].is_null()) { 107 break; 108 } 109 fn(cur->data[i]); 110 } 111 cur = cur->next; 112 num_chunks++; 113 } 114 } 115 #endif 116 117 // It scans an object and visits its children. 118 inline void G1CMTask::scan_task_entry(G1TaskQueueEntry task_entry) { process_grey_task_entry<true>(task_entry); } 119 120 inline void G1CMTask::push(G1TaskQueueEntry task_entry) { 121 assert(task_entry.is_array_slice() || _g1h->is_in_g1_reserved(task_entry.obj()), "invariant"); 122 assert(task_entry.is_array_slice() || !_g1h->is_on_master_free_list( 123 _g1h->heap_region_containing(task_entry.obj())), "invariant"); 124 assert(task_entry.is_array_slice() || !_g1h->is_obj_ill(task_entry.obj()), "invariant"); // FIXME!!! 125 assert(task_entry.is_array_slice() || _nextMarkBitMap->isMarked((HeapWord*)task_entry.obj()), "invariant"); 126 127 if (!_task_queue->push(task_entry)) { 128 // The local task queue looks full. We need to push some entries 129 // to the global stack. 130 move_entries_to_global_stack(); 131 132 // this should succeed since, even if we overflow the global 133 // stack, we should have definitely removed some entries from the 134 // local queue. So, there must be space on it. 135 bool success = _task_queue->push(task_entry); 136 assert(success, "invariant"); 137 } 138 } 139 140 inline bool G1CMTask::is_below_finger(oop obj, HeapWord* global_finger) const { 141 // If obj is above the global finger, then the mark bitmap scan 142 // will find it later, and no push is needed. Similarly, if we have 143 // a current region and obj is between the local finger and the 144 // end of the current region, then no push is needed. The tradeoff 145 // of checking both vs only checking the global finger is that the 146 // local check will be more accurate and so result in fewer pushes, 147 // but may also be a little slower. 148 HeapWord* objAddr = (HeapWord*)obj; 149 if (_finger != NULL) { 150 // We have a current region. 151 152 // Finger and region values are all NULL or all non-NULL. We 153 // use _finger to check since we immediately use its value. 154 assert(_curr_region != NULL, "invariant"); 155 assert(_region_limit != NULL, "invariant"); 156 assert(_region_limit <= global_finger, "invariant"); 157 158 // True if obj is less than the local finger, or is between 159 // the region limit and the global finger. 160 if (objAddr < _finger) { 161 return true; 162 } else if (objAddr < _region_limit) { 163 return false; 164 } // Else check global finger. 165 } 166 // Check global finger. 167 return objAddr < global_finger; 168 } 169 170 template<bool scan> 171 inline void G1CMTask::process_grey_task_entry(G1TaskQueueEntry task_entry) { 172 assert(scan || (task_entry.is_oop() && task_entry.obj()->is_typeArray()), "Skipping scan of grey non-typeArray"); 173 assert(task_entry.is_array_slice() || _nextMarkBitMap->isMarked((HeapWord*)task_entry.obj()), 174 "Any stolen object should be a slice or marked"); 175 176 if (scan) { 177 if (task_entry.is_array_slice()) { 178 _words_scanned += _objArray_processor.process_slice(task_entry.slice()); 179 } else { 180 oop obj = task_entry.obj(); 181 if (G1CMObjArrayProcessor::should_be_sliced(obj)) { 182 _words_scanned += _objArray_processor.process_obj(obj); 183 } else { 184 _words_scanned += obj->oop_iterate_size(_cm_oop_closure);; 185 } 186 } 187 } 188 check_limits(); 189 } 190 191 inline size_t G1CMTask::scan_objArray(objArrayOop obj, MemRegion mr) { 192 obj->oop_iterate(_cm_oop_closure, mr); 193 return mr.word_size(); 194 } 195 196 inline void G1CMTask::make_reference_grey(oop obj) { 197 if (_cm->par_mark(obj)) { 198 // No OrderAccess:store_load() is needed. It is implicit in the 199 // CAS done in G1CMBitMap::parMark() call in the routine above. 200 HeapWord* global_finger = _cm->finger(); 201 202 // We only need to push a newly grey object on the mark 203 // stack if it is in a section of memory the mark bitmap 204 // scan has already examined. Mark bitmap scanning 205 // maintains progress "fingers" for determining that. 206 // 207 // Notice that the global finger might be moving forward 208 // concurrently. This is not a problem. In the worst case, we 209 // mark the object while it is above the global finger and, by 210 // the time we read the global finger, it has moved forward 211 // past this object. In this case, the object will probably 212 // be visited when a task is scanning the region and will also 213 // be pushed on the stack. So, some duplicate work, but no 214 // correctness problems. 215 if (is_below_finger(obj, global_finger)) { 216 G1TaskQueueEntry entry = G1TaskQueueEntry::from_oop(obj); 217 if (obj->is_typeArray()) { 218 // Immediately process arrays of primitive types, rather 219 // than pushing on the mark stack. This keeps us from 220 // adding humongous objects to the mark stack that might 221 // be reclaimed before the entry is processed - see 222 // selection of candidates for eager reclaim of humongous 223 // objects. The cost of the additional type test is 224 // mitigated by avoiding a trip through the mark stack, 225 // by only doing a bookkeeping update and avoiding the 226 // actual scan of the object - a typeArray contains no 227 // references, and the metadata is built-in. 228 process_grey_task_entry<false>(entry); 229 } else { 230 push(entry); 231 } 232 } 233 } 234 } 235 236 inline void G1CMTask::deal_with_reference(oop obj) { 237 increment_refs_reached(); 238 239 HeapWord* objAddr = (HeapWord*) obj; 240 assert(obj->is_oop_or_null(true /* ignore mark word */), "Expected an oop or NULL at " PTR_FORMAT, p2i(obj)); 241 if (_g1h->is_in_g1_reserved(objAddr)) { 242 assert(obj != NULL, "null check is implicit"); 243 if (!_nextMarkBitMap->isMarked(objAddr)) { 244 // Only get the containing region if the object is not marked on the 245 // bitmap (otherwise, it's a waste of time since we won't do 246 // anything with it). 247 HeapRegion* hr = _g1h->heap_region_containing(obj); 248 if (!hr->obj_allocated_since_next_marking(obj)) { 249 make_reference_grey(obj); 250 } 251 } 252 } 253 } 254 255 inline void G1ConcurrentMark::markPrev(oop p) { 256 assert(!_prevMarkBitMap->isMarked((HeapWord*) p), "sanity"); 257 // Note we are overriding the read-only view of the prev map here, via 258 // the cast. 259 ((G1CMBitMap*)_prevMarkBitMap)->mark((HeapWord*) p); 260 } 261 262 bool G1ConcurrentMark::isPrevMarked(oop p) const { 263 assert(p != NULL && p->is_oop(), "expected an oop"); 264 HeapWord* addr = (HeapWord*)p; 265 assert(addr >= _prevMarkBitMap->startWord() || 266 addr < _prevMarkBitMap->endWord(), "in a region"); 267 268 return _prevMarkBitMap->isMarked(addr); 269 } 270 271 inline void G1ConcurrentMark::grayRoot(oop obj, HeapRegion* hr) { 272 assert(obj != NULL, "pre-condition"); 273 HeapWord* addr = (HeapWord*) obj; 274 if (hr == NULL) { 275 hr = _g1h->heap_region_containing(addr); 276 } else { 277 assert(hr->is_in(addr), "pre-condition"); 278 } 279 assert(hr != NULL, "sanity"); 280 // Given that we're looking for a region that contains an object 281 // header it's impossible to get back a HC region. 282 assert(!hr->is_continues_humongous(), "sanity"); 283 284 if (addr < hr->next_top_at_mark_start()) { 285 if (!_nextMarkBitMap->isMarked(addr)) { 286 par_mark(obj); 287 } 288 } 289 } 290 291 inline bool G1ConcurrentMark::do_yield_check() { 292 if (SuspendibleThreadSet::should_yield()) { 293 SuspendibleThreadSet::yield(); 294 return true; 295 } else { 296 return false; 297 } 298 } 299 300 #endif // SHARE_VM_GC_G1_G1CONCURRENTMARK_INLINE_HPP