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->par_mark((HeapWord*)obj); 37 } 38 39 inline bool G1CMBitMap::iterate(G1CMBitMapClosure* cl, MemRegion mr) { 40 HeapWord* start_addr = MAX2(_covered.start(), mr.start()); 41 HeapWord* const end_addr = MIN2(_covered.end(), mr.end()); 42 43 if (end_addr > start_addr) { 44 // Right-open interval [start-offset, end-offset). 45 BitMap::idx_t start_offset = addr_to_offset(start_addr); 46 BitMap::idx_t const end_offset = addr_to_offset(end_addr); 47 48 start_offset = _bm.get_next_one_offset(start_offset, end_offset); 49 while (start_offset < end_offset) { 50 start_addr = offset_to_addr(start_offset); 51 if (!cl->do_addr(start_addr)) { 52 return false; 53 } 54 HeapWord* next_addr = MIN2(addr_after_obj(start_addr), end_addr); 55 BitMap::idx_t const next_offset = addr_to_offset(next_addr); 56 start_offset = _bm.get_next_one_offset(next_offset, end_offset); 57 } 58 } 59 return true; 60 } 61 62 inline HeapWord* G1CMBitMap::get_next_marked_addr(const HeapWord* addr, 63 const HeapWord* limit) const { 64 // First we must round addr *up* to a possible object boundary. 65 addr = (HeapWord*)align_up(addr, HeapWordSize << _shifter); 66 size_t addrOffset = addr_to_offset(addr); 67 assert(limit != NULL, "limit must not be NULL"); 68 size_t limitOffset = addr_to_offset(limit); 69 size_t nextOffset = _bm.get_next_one_offset(addrOffset, limitOffset); 70 HeapWord* nextAddr = offset_to_addr(nextOffset); 71 assert(nextAddr >= addr, "get_next_one postcondition"); 72 assert(nextAddr == limit || is_marked(nextAddr), 73 "get_next_one postcondition"); 74 return nextAddr; 75 } 76 77 inline HeapWord* G1CMBitMap::addr_after_obj(HeapWord* addr) { 78 return addr + ((oop)addr)->size(); 79 } 80 81 #ifdef ASSERT 82 inline void G1CMBitMap::check_mark(HeapWord* addr) { 83 assert(G1CollectedHeap::heap()->is_in_exact(addr), 84 "Trying to access bitmap " PTR_FORMAT " for address " PTR_FORMAT " not in the heap.", 85 p2i(this), p2i(addr)); 86 } 87 #endif 88 89 inline void G1CMBitMap::mark(HeapWord* addr) { 90 check_mark(addr); 91 _bm.set_bit(addr_to_offset(addr)); 92 } 93 94 inline void G1CMBitMap::clear(HeapWord* addr) { 95 check_mark(addr); 96 _bm.clear_bit(addr_to_offset(addr)); 97 } 98 99 inline bool G1CMBitMap::par_mark(HeapWord* addr) { 100 check_mark(addr); 101 return _bm.par_set_bit(addr_to_offset(addr)); 102 } 103 104 #ifndef PRODUCT 105 template<typename Fn> 106 inline void G1CMMarkStack::iterate(Fn fn) const { 107 assert_at_safepoint(true); 108 109 size_t num_chunks = 0; 110 111 TaskQueueEntryChunk* cur = _chunk_list; 112 while (cur != NULL) { 113 guarantee(num_chunks <= _chunks_in_chunk_list, "Found " SIZE_FORMAT " oop chunks which is more than there should be", num_chunks); 114 115 for (size_t i = 0; i < EntriesPerChunk; ++i) { 116 if (cur->data[i].is_null()) { 117 break; 118 } 119 fn(cur->data[i]); 120 } 121 cur = cur->next; 122 num_chunks++; 123 } 124 } 125 #endif 126 127 // It scans an object and visits its children. 128 inline void G1CMTask::scan_task_entry(G1TaskQueueEntry task_entry) { process_grey_task_entry<true>(task_entry); } 129 130 inline void G1CMTask::push(G1TaskQueueEntry task_entry) { 131 assert(task_entry.is_array_slice() || _g1h->is_in_g1_reserved(task_entry.obj()), "invariant"); 132 assert(task_entry.is_array_slice() || !_g1h->is_on_master_free_list( 133 _g1h->heap_region_containing(task_entry.obj())), "invariant"); 134 assert(task_entry.is_array_slice() || !_g1h->is_obj_ill(task_entry.obj()), "invariant"); // FIXME!!! 135 assert(task_entry.is_array_slice() || _nextMarkBitMap->is_marked((HeapWord*)task_entry.obj()), "invariant"); 136 137 if (!_task_queue->push(task_entry)) { 138 // The local task queue looks full. We need to push some entries 139 // to the global stack. 140 move_entries_to_global_stack(); 141 142 // this should succeed since, even if we overflow the global 143 // stack, we should have definitely removed some entries from the 144 // local queue. So, there must be space on it. 145 bool success = _task_queue->push(task_entry); 146 assert(success, "invariant"); 147 } 148 } 149 150 inline bool G1CMTask::is_below_finger(oop obj, HeapWord* global_finger) const { 151 // If obj is above the global finger, then the mark bitmap scan 152 // will find it later, and no push is needed. Similarly, if we have 153 // a current region and obj is between the local finger and the 154 // end of the current region, then no push is needed. The tradeoff 155 // of checking both vs only checking the global finger is that the 156 // local check will be more accurate and so result in fewer pushes, 157 // but may also be a little slower. 158 HeapWord* objAddr = (HeapWord*)obj; 159 if (_finger != NULL) { 160 // We have a current region. 161 162 // Finger and region values are all NULL or all non-NULL. We 163 // use _finger to check since we immediately use its value. 164 assert(_curr_region != NULL, "invariant"); 165 assert(_region_limit != NULL, "invariant"); 166 assert(_region_limit <= global_finger, "invariant"); 167 168 // True if obj is less than the local finger, or is between 169 // the region limit and the global finger. 170 if (objAddr < _finger) { 171 return true; 172 } else if (objAddr < _region_limit) { 173 return false; 174 } // Else check global finger. 175 } 176 // Check global finger. 177 return objAddr < global_finger; 178 } 179 180 template<bool scan> 181 inline void G1CMTask::process_grey_task_entry(G1TaskQueueEntry task_entry) { 182 assert(scan || (task_entry.is_oop() && task_entry.obj()->is_typeArray()), "Skipping scan of grey non-typeArray"); 183 assert(task_entry.is_array_slice() || _nextMarkBitMap->is_marked((HeapWord*)task_entry.obj()), 184 "Any stolen object should be a slice or marked"); 185 186 if (scan) { 187 if (task_entry.is_array_slice()) { 188 _words_scanned += _objArray_processor.process_slice(task_entry.slice()); 189 } else { 190 oop obj = task_entry.obj(); 191 if (G1CMObjArrayProcessor::should_be_sliced(obj)) { 192 _words_scanned += _objArray_processor.process_obj(obj); 193 } else { 194 _words_scanned += obj->oop_iterate_size(_cm_oop_closure);; 195 } 196 } 197 } 198 check_limits(); 199 } 200 201 inline size_t G1CMTask::scan_objArray(objArrayOop obj, MemRegion mr) { 202 obj->oop_iterate(_cm_oop_closure, mr); 203 return mr.word_size(); 204 } 205 206 inline void G1CMTask::make_reference_grey(oop obj) { 207 if (_cm->par_mark(obj)) { 208 // No OrderAccess:store_load() is needed. It is implicit in the 209 // CAS done in G1CMBitMap::parMark() call in the routine above. 210 HeapWord* global_finger = _cm->finger(); 211 212 // We only need to push a newly grey object on the mark 213 // stack if it is in a section of memory the mark bitmap 214 // scan has already examined. Mark bitmap scanning 215 // maintains progress "fingers" for determining that. 216 // 217 // Notice that the global finger might be moving forward 218 // concurrently. This is not a problem. In the worst case, we 219 // mark the object while it is above the global finger and, by 220 // the time we read the global finger, it has moved forward 221 // past this object. In this case, the object will probably 222 // be visited when a task is scanning the region and will also 223 // be pushed on the stack. So, some duplicate work, but no 224 // correctness problems. 225 if (is_below_finger(obj, global_finger)) { 226 G1TaskQueueEntry entry = G1TaskQueueEntry::from_oop(obj); 227 if (obj->is_typeArray()) { 228 // Immediately process arrays of primitive types, rather 229 // than pushing on the mark stack. This keeps us from 230 // adding humongous objects to the mark stack that might 231 // be reclaimed before the entry is processed - see 232 // selection of candidates for eager reclaim of humongous 233 // objects. The cost of the additional type test is 234 // mitigated by avoiding a trip through the mark stack, 235 // by only doing a bookkeeping update and avoiding the 236 // actual scan of the object - a typeArray contains no 237 // references, and the metadata is built-in. 238 process_grey_task_entry<false>(entry); 239 } else { 240 push(entry); 241 } 242 } 243 } 244 } 245 246 inline void G1CMTask::deal_with_reference(oop obj) { 247 increment_refs_reached(); 248 249 HeapWord* objAddr = (HeapWord*) obj; 250 assert(obj->is_oop_or_null(true /* ignore mark word */), "Expected an oop or NULL at " PTR_FORMAT, p2i(obj)); 251 if (_g1h->is_in_g1_reserved(objAddr)) { 252 assert(obj != NULL, "null check is implicit"); 253 if (!_nextMarkBitMap->is_marked(objAddr)) { 254 // Only get the containing region if the object is not marked on the 255 // bitmap (otherwise, it's a waste of time since we won't do 256 // anything with it). 257 HeapRegion* hr = _g1h->heap_region_containing(obj); 258 if (!hr->obj_allocated_since_next_marking(obj)) { 259 make_reference_grey(obj); 260 } 261 } 262 } 263 } 264 265 inline void G1ConcurrentMark::markPrev(oop p) { 266 assert(!_prevMarkBitMap->is_marked((HeapWord*) p), "sanity"); 267 _prevMarkBitMap->mark((HeapWord*) p); 268 } 269 270 bool G1ConcurrentMark::isPrevMarked(oop p) const { 271 assert(p != NULL && p->is_oop(), "expected an oop"); 272 return _prevMarkBitMap->is_marked((HeapWord*)p); 273 } 274 275 inline void G1ConcurrentMark::grayRoot(oop obj, HeapRegion* hr) { 276 assert(obj != NULL, "pre-condition"); 277 HeapWord* addr = (HeapWord*) obj; 278 if (hr == NULL) { 279 hr = _g1h->heap_region_containing(addr); 280 } else { 281 assert(hr->is_in(addr), "pre-condition"); 282 } 283 assert(hr != NULL, "sanity"); 284 // Given that we're looking for a region that contains an object 285 // header it's impossible to get back a HC region. 286 assert(!hr->is_continues_humongous(), "sanity"); 287 288 if (addr < hr->next_top_at_mark_start()) { 289 if (!_nextMarkBitMap->is_marked(addr)) { 290 par_mark(obj); 291 } 292 } 293 } 294 295 inline bool G1ConcurrentMark::do_yield_check() { 296 if (SuspendibleThreadSet::should_yield()) { 297 SuspendibleThreadSet::yield(); 298 return true; 299 } else { 300 return false; 301 } 302 } 303 304 #endif // SHARE_VM_GC_G1_G1CONCURRENTMARK_INLINE_HPP