1 /* 2 * Copyright (c) 2001, 2016, 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 34 inline bool G1ConcurrentMark::par_mark(oop obj) { 35 return _nextMarkBitMap->parMark((HeapWord*)obj); 36 } 37 38 inline bool G1CMBitMapRO::iterate(BitMapClosure* cl, MemRegion mr) { 39 HeapWord* start_addr = MAX2(startWord(), mr.start()); 40 HeapWord* end_addr = MIN2(endWord(), mr.end()); 41 42 if (end_addr > start_addr) { 43 // Right-open interval [start-offset, end-offset). 44 BitMap::idx_t start_offset = heapWordToOffset(start_addr); 45 BitMap::idx_t end_offset = heapWordToOffset(end_addr); 46 47 start_offset = _bm.get_next_one_offset(start_offset, end_offset); 48 while (start_offset < end_offset) { 49 if (!cl->do_bit(start_offset)) { 50 return false; 51 } 52 HeapWord* next_addr = MIN2(nextObject(offsetToHeapWord(start_offset)), end_addr); 53 BitMap::idx_t next_offset = heapWordToOffset(next_addr); 54 start_offset = _bm.get_next_one_offset(next_offset, end_offset); 55 } 56 } 57 return true; 58 } 59 60 // The argument addr should be the start address of a valid object 61 HeapWord* G1CMBitMapRO::nextObject(HeapWord* addr) { 62 oop obj = (oop) addr; 63 HeapWord* res = addr + obj->size(); 64 assert(offsetToHeapWord(heapWordToOffset(res)) == res, "sanity"); 65 return res; 66 } 67 68 #define check_mark(addr) \ 69 assert(_bmStartWord <= (addr) && (addr) < (_bmStartWord + _bmWordSize), \ 70 "outside underlying space?"); \ 71 assert(G1CollectedHeap::heap()->is_in_exact(addr), \ 72 "Trying to access not available bitmap " PTR_FORMAT \ 73 " corresponding to " PTR_FORMAT " (%u)", \ 74 p2i(this), p2i(addr), G1CollectedHeap::heap()->addr_to_region(addr)); 75 76 inline void G1CMBitMap::mark(HeapWord* addr) { 77 check_mark(addr); 78 _bm.set_bit(heapWordToOffset(addr)); 79 } 80 81 inline void G1CMBitMap::clear(HeapWord* addr) { 82 check_mark(addr); 83 _bm.clear_bit(heapWordToOffset(addr)); 84 } 85 86 inline bool G1CMBitMap::parMark(HeapWord* addr) { 87 check_mark(addr); 88 return _bm.par_set_bit(heapWordToOffset(addr)); 89 } 90 91 #undef check_mark 92 93 #ifndef PRODUCT 94 template<typename Fn> 95 inline void G1CMMarkStack::iterate(Fn fn) const { 96 assert_at_safepoint(true); 97 98 size_t num_chunks = 0; 99 100 OopChunk* cur = _chunk_list; 101 while (cur != NULL) { 102 guarantee(num_chunks <= _chunks_in_chunk_list, "Found " SIZE_FORMAT " oop chunks which is more than there should be", num_chunks); 103 104 for (size_t i = 0; i < OopsPerChunk; ++i) { 105 if (cur->data[i] == NULL) { 106 break; 107 } 108 fn(cur->data[i]); 109 } 110 cur = cur->next; 111 num_chunks++; 112 } 113 } 114 #endif 115 116 // It scans an object and visits its children. 117 inline void G1CMTask::scan_object(oop obj) { process_grey_object<true>(obj); } 118 119 inline void G1CMTask::push(oop obj) { 120 HeapWord* objAddr = (HeapWord*) obj; 121 assert(G1CMObjArrayProcessor::is_array_slice(obj) || _g1h->is_in_g1_reserved(objAddr), "invariant"); 122 assert(G1CMObjArrayProcessor::is_array_slice(obj) || !_g1h->is_on_master_free_list( 123 _g1h->heap_region_containing((HeapWord*) objAddr)), "invariant"); 124 assert(G1CMObjArrayProcessor::is_array_slice(obj) || !_g1h->is_obj_ill(obj), "invariant"); 125 assert(G1CMObjArrayProcessor::is_array_slice(obj) || _nextMarkBitMap->isMarked(objAddr), "invariant"); 126 127 if (!_task_queue->push(obj)) { 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(obj); 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_object(oop obj) { 172 assert(scan || obj->is_typeArray(), "Skipping scan of grey non-typeArray"); 173 assert(G1CMObjArrayProcessor::is_array_slice(obj) || _nextMarkBitMap->isMarked((HeapWord*) obj), 174 "Any stolen object should be a slice or marked"); 175 176 if (scan) { 177 if (G1CMObjArrayProcessor::is_array_slice(obj)) { 178 _words_scanned += _objArray_processor.process_slice(obj); 179 } else if (G1CMObjArrayProcessor::should_be_sliced(obj)) { 180 _words_scanned += _objArray_processor.process_obj(obj); 181 } else { 182 _words_scanned += obj->oop_iterate_size(_cm_oop_closure);; 183 } 184 } 185 check_limits(); 186 } 187 188 inline size_t G1CMTask::scan_objArray(objArrayOop obj, MemRegion mr) { 189 obj->oop_iterate(_cm_oop_closure, mr); 190 return mr.word_size(); 191 } 192 193 inline void G1CMTask::make_reference_grey(oop obj) { 194 if (_cm->par_mark(obj)) { 195 // No OrderAccess:store_load() is needed. It is implicit in the 196 // CAS done in G1CMBitMap::parMark() call in the routine above. 197 HeapWord* global_finger = _cm->finger(); 198 199 // We only need to push a newly grey object on the mark 200 // stack if it is in a section of memory the mark bitmap 201 // scan has already examined. Mark bitmap scanning 202 // maintains progress "fingers" for determining that. 203 // 204 // Notice that the global finger might be moving forward 205 // concurrently. This is not a problem. In the worst case, we 206 // mark the object while it is above the global finger and, by 207 // the time we read the global finger, it has moved forward 208 // past this object. In this case, the object will probably 209 // be visited when a task is scanning the region and will also 210 // be pushed on the stack. So, some duplicate work, but no 211 // correctness problems. 212 if (is_below_finger(obj, global_finger)) { 213 if (obj->is_typeArray()) { 214 // Immediately process arrays of primitive types, rather 215 // than pushing on the mark stack. This keeps us from 216 // adding humongous objects to the mark stack that might 217 // be reclaimed before the entry is processed - see 218 // selection of candidates for eager reclaim of humongous 219 // objects. The cost of the additional type test is 220 // mitigated by avoiding a trip through the mark stack, 221 // by only doing a bookkeeping update and avoiding the 222 // actual scan of the object - a typeArray contains no 223 // references, and the metadata is built-in. 224 process_grey_object<false>(obj); 225 } else { 226 push(obj); 227 } 228 } 229 } 230 } 231 232 inline void G1CMTask::deal_with_reference(oop obj) { 233 increment_refs_reached(); 234 235 HeapWord* objAddr = (HeapWord*) obj; 236 assert(obj->is_oop_or_null(true /* ignore mark word */), "Expected an oop or NULL at " PTR_FORMAT, p2i(obj)); 237 if (_g1h->is_in_g1_reserved(objAddr)) { 238 assert(obj != NULL, "null check is implicit"); 239 if (!_nextMarkBitMap->isMarked(objAddr)) { 240 // Only get the containing region if the object is not marked on the 241 // bitmap (otherwise, it's a waste of time since we won't do 242 // anything with it). 243 HeapRegion* hr = _g1h->heap_region_containing(obj); 244 if (!hr->obj_allocated_since_next_marking(obj)) { 245 make_reference_grey(obj); 246 } 247 } 248 } 249 } 250 251 inline void G1ConcurrentMark::markPrev(oop p) { 252 assert(!_prevMarkBitMap->isMarked((HeapWord*) p), "sanity"); 253 // Note we are overriding the read-only view of the prev map here, via 254 // the cast. 255 ((G1CMBitMap*)_prevMarkBitMap)->mark((HeapWord*) p); 256 } 257 258 bool G1ConcurrentMark::isPrevMarked(oop p) const { 259 assert(p != NULL && p->is_oop(), "expected an oop"); 260 HeapWord* addr = (HeapWord*)p; 261 assert(addr >= _prevMarkBitMap->startWord() || 262 addr < _prevMarkBitMap->endWord(), "in a region"); 263 264 return _prevMarkBitMap->isMarked(addr); 265 } 266 267 inline void G1ConcurrentMark::grayRoot(oop obj, HeapRegion* hr) { 268 assert(obj != NULL, "pre-condition"); 269 HeapWord* addr = (HeapWord*) obj; 270 if (hr == NULL) { 271 hr = _g1h->heap_region_containing(addr); 272 } else { 273 assert(hr->is_in(addr), "pre-condition"); 274 } 275 assert(hr != NULL, "sanity"); 276 // Given that we're looking for a region that contains an object 277 // header it's impossible to get back a HC region. 278 assert(!hr->is_continues_humongous(), "sanity"); 279 280 if (addr < hr->next_top_at_mark_start()) { 281 if (!_nextMarkBitMap->isMarked(addr)) { 282 par_mark(obj); 283 } 284 } 285 } 286 287 inline bool G1ConcurrentMark::do_yield_check() { 288 if (SuspendibleThreadSet::should_yield()) { 289 SuspendibleThreadSet::yield(); 290 return true; 291 } else { 292 return false; 293 } 294 } 295 296 #endif // SHARE_VM_GC_G1_G1CONCURRENTMARK_INLINE_HPP