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_G1OOPCLOSURES_INLINE_HPP 26 #define SHARE_VM_GC_G1_G1OOPCLOSURES_INLINE_HPP 27 28 #include "gc/g1/g1CollectedHeap.hpp" 29 #include "gc/g1/g1ConcurrentMark.inline.hpp" 30 #include "gc/g1/g1OopClosures.hpp" 31 #include "gc/g1/g1ParScanThreadState.inline.hpp" 32 #include "gc/g1/g1RemSet.hpp" 33 #include "gc/g1/g1RemSet.inline.hpp" 34 #include "gc/g1/heapRegion.inline.hpp" 35 #include "gc/g1/heapRegionRemSet.hpp" 36 #include "memory/iterator.inline.hpp" 37 #include "runtime/prefetch.inline.hpp" 38 39 // This closure is applied to the fields of the objects that have just been copied. 40 template <class T> 41 inline void G1ParScanClosure::do_oop_nv(T* p) { 42 T heap_oop = oopDesc::load_heap_oop(p); 43 44 if (!oopDesc::is_null(heap_oop)) { 45 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 46 const InCSetState state = _g1->in_cset_state(obj); 47 if (state.is_in_cset()) { 48 // We're not going to even bother checking whether the object is 49 // already forwarded or not, as this usually causes an immediate 50 // stall. We'll try to prefetch the object (for write, given that 51 // we might need to install the forwarding reference) and we'll 52 // get back to it when pop it from the queue 53 Prefetch::write(obj->mark_addr(), 0); 54 Prefetch::read(obj->mark_addr(), (HeapWordSize*2)); 55 56 // slightly paranoid test; I'm trying to catch potential 57 // problems before we go into push_on_queue to know where the 58 // problem is coming from 59 assert((obj == oopDesc::load_decode_heap_oop(p)) || 60 (obj->is_forwarded() && 61 obj->forwardee() == oopDesc::load_decode_heap_oop(p)), 62 "p should still be pointing to obj or to its forwardee"); 63 64 _par_scan_state->push_on_queue(p); 65 } else { 66 if (state.is_humongous()) { 67 _g1->set_humongous_is_live(obj); 68 } else if (state.is_ext()) { 69 _par_scan_state->do_oop_ext(p); 70 } 71 _par_scan_state->update_rs(_from, p, obj); 72 } 73 } 74 } 75 76 template <class T> 77 inline void G1ParPushHeapRSClosure::do_oop_nv(T* p) { 78 T heap_oop = oopDesc::load_heap_oop(p); 79 80 if (!oopDesc::is_null(heap_oop)) { 81 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 82 const InCSetState state = _g1->in_cset_state(obj); 83 if (state.is_in_cset_or_humongous()) { 84 Prefetch::write(obj->mark_addr(), 0); 85 Prefetch::read(obj->mark_addr(), (HeapWordSize*2)); 86 87 // Place on the references queue 88 _par_scan_state->push_on_queue(p); 89 } else if (state.is_ext()) { 90 _par_scan_state->do_oop_ext(p); 91 } else { 92 assert(!_g1->is_in_cset(obj), "checking"); 93 } 94 } 95 } 96 97 template <class T> 98 inline void G1CMOopClosure::do_oop_nv(T* p) { 99 oop obj = oopDesc::load_decode_heap_oop(p); 100 _task->deal_with_reference(obj); 101 } 102 103 template <class T> 104 inline void G1RootRegionScanClosure::do_oop_nv(T* p) { 105 T heap_oop = oopDesc::load_heap_oop(p); 106 if (!oopDesc::is_null(heap_oop)) { 107 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 108 HeapRegion* hr = _g1h->heap_region_containing((HeapWord*) obj); 109 _cm->grayRoot(obj, hr); 110 } 111 } 112 113 template <class T> 114 inline static void check_obj_during_refinement(T* p, oop const obj) { 115 #ifdef ASSERT 116 G1CollectedHeap* g1 = G1CollectedHeap::heap(); 117 // can't do because of races 118 // assert(obj == NULL || obj->is_oop(), "expected an oop"); 119 assert(check_obj_alignment(obj), "not oop aligned"); 120 assert(g1->is_in_reserved(obj), "must be in heap"); 121 122 HeapRegion* from = g1->heap_region_containing(p); 123 124 assert(from != NULL, "from region must be non-NULL"); 125 assert(from->is_in_reserved(p) || 126 (from->is_humongous() && 127 g1->heap_region_containing(p)->is_humongous() && 128 from->humongous_start_region() == g1->heap_region_containing(p)->humongous_start_region()), 129 "p " PTR_FORMAT " is not in the same region %u or part of the correct humongous object starting at region %u.", 130 p2i(p), from->hrm_index(), from->humongous_start_region()->hrm_index()); 131 #endif // ASSERT 132 } 133 134 template <class T> 135 inline void G1ConcurrentRefineOopClosure::do_oop_nv(T* p) { 136 T o = oopDesc::load_heap_oop(p); 137 if (oopDesc::is_null(o)) { 138 return; 139 } 140 oop obj = oopDesc::decode_heap_oop_not_null(o); 141 142 check_obj_during_refinement(p, obj); 143 144 if (HeapRegion::is_in_same_region(p, obj)) { 145 // Normally this closure should only be called with cross-region references. 146 // But since Java threads are manipulating the references concurrently and we 147 // reload the values things may have changed. 148 // This check lets slip through references from a humongous continues region 149 // to its humongous start region, as they are in different regions, and adds a 150 // remembered set entry. This is benign (apart from memory usage), as this 151 // closure is never called during evacuation. 152 return; 153 } 154 155 HeapRegion* to = _g1->heap_region_containing(obj); 156 157 assert(to->rem_set() != NULL, "Need per-region 'into' remsets."); 158 to->rem_set()->add_reference(p, _worker_i); 159 } 160 161 template <class T> 162 inline void G1UpdateRSOrPushRefOopClosure::do_oop_nv(T* p) { 163 oop obj = oopDesc::load_decode_heap_oop(p); 164 if (obj == NULL) { 165 return; 166 } 167 168 #ifdef ASSERT 169 // can't do because of races 170 // assert(obj == NULL || obj->is_oop(), "expected an oop"); 171 assert(check_obj_alignment(obj), "not oop aligned"); 172 assert(_g1->is_in_reserved(obj), "must be in heap"); 173 #endif // ASSERT 174 175 assert(_from != NULL, "from region must be non-NULL"); 176 assert(_from->is_in_reserved(p) || 177 (_from->is_humongous() && 178 _g1->heap_region_containing(p)->is_humongous() && 179 _from->humongous_start_region() == _g1->heap_region_containing(p)->humongous_start_region()), 180 "p " PTR_FORMAT " is not in the same region %u or part of the correct humongous object starting at region %u.", 181 p2i(p), _from->hrm_index(), _from->humongous_start_region()->hrm_index()); 182 183 HeapRegion* to = _g1->heap_region_containing(obj); 184 if (_from == to) { 185 // Normally this closure should only be called with cross-region references. 186 // But since Java threads are manipulating the references concurrently and we 187 // reload the values things may have changed. 188 // Also this check lets slip through references from a humongous continues region 189 // to its humongous start region, as they are in different regions, and adds a 190 // remembered set entry. This is benign (apart from memory usage), as we never 191 // try to either evacuate or eager reclaim these kind of regions. 192 return; 193 } 194 195 // The _record_refs_into_cset flag is true during the RSet 196 // updating part of an evacuation pause. It is false at all 197 // other times: 198 // * rebuilding the remembered sets after a full GC 199 // * during concurrent refinement. 200 // * updating the remembered sets of regions in the collection 201 // set in the event of an evacuation failure (when deferred 202 // updates are enabled). 203 204 if (_record_refs_into_cset && to->in_collection_set()) { 205 // We are recording references that point into the collection 206 // set and this particular reference does exactly that... 207 // If the referenced object has already been forwarded 208 // to itself, we are handling an evacuation failure and 209 // we have already visited/tried to copy this object 210 // there is no need to retry. 211 if (!self_forwarded(obj)) { 212 assert(_push_ref_cl != NULL, "should not be null"); 213 // Push the reference in the refs queue of the G1ParScanThreadState 214 // instance for this worker thread. 215 _push_ref_cl->do_oop(p); 216 } 217 _has_refs_into_cset = true; 218 219 // Deferred updates to the CSet are either discarded (in the normal case), 220 // or processed (if an evacuation failure occurs) at the end 221 // of the collection. 222 // See G1RemSet::cleanup_after_oops_into_collection_set_do(). 223 } else { 224 // We either don't care about pushing references that point into the 225 // collection set (i.e. we're not during an evacuation pause) _or_ 226 // the reference doesn't point into the collection set. Either way 227 // we add the reference directly to the RSet of the region containing 228 // the referenced object. 229 assert(to->rem_set() != NULL, "Need per-region 'into' remsets."); 230 to->rem_set()->add_reference(p, _worker_i); 231 } 232 } 233 void G1UpdateRSOrPushRefOopClosure::do_oop(oop* p) { do_oop_nv(p); } 234 void G1UpdateRSOrPushRefOopClosure::do_oop(narrowOop* p) { do_oop_nv(p); } 235 236 template <class T> 237 void G1ParCopyHelper::do_klass_barrier(T* p, oop new_obj) { 238 if (_g1->heap_region_containing(new_obj)->is_young()) { 239 _scanned_klass->record_modified_oops(); 240 } 241 } 242 243 void G1ParCopyHelper::mark_object(oop obj) { 244 assert(!_g1->heap_region_containing(obj)->in_collection_set(), "should not mark objects in the CSet"); 245 246 // We know that the object is not moving so it's safe to read its size. 247 _cm->grayRoot(obj); 248 } 249 250 void G1ParCopyHelper::mark_forwarded_object(oop from_obj, oop to_obj) { 251 assert(from_obj->is_forwarded(), "from obj should be forwarded"); 252 assert(from_obj->forwardee() == to_obj, "to obj should be the forwardee"); 253 assert(from_obj != to_obj, "should not be self-forwarded"); 254 255 assert(_g1->heap_region_containing(from_obj)->in_collection_set(), "from obj should be in the CSet"); 256 assert(!_g1->heap_region_containing(to_obj)->in_collection_set(), "should not mark objects in the CSet"); 257 258 // The object might be in the process of being copied by another 259 // worker so we cannot trust that its to-space image is 260 // well-formed. So we have to read its size from its from-space 261 // image which we know should not be changing. 262 _cm->grayRoot(to_obj); 263 } 264 265 template <G1Barrier barrier, G1Mark do_mark_object, bool use_ext> 266 template <class T> 267 void G1ParCopyClosure<barrier, do_mark_object, use_ext>::do_oop_work(T* p) { 268 T heap_oop = oopDesc::load_heap_oop(p); 269 270 if (oopDesc::is_null(heap_oop)) { 271 return; 272 } 273 274 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 275 276 assert(_worker_id == _par_scan_state->worker_id(), "sanity"); 277 278 const InCSetState state = _g1->in_cset_state(obj); 279 if (state.is_in_cset()) { 280 oop forwardee; 281 markOop m = obj->mark(); 282 if (m->is_marked()) { 283 forwardee = (oop) m->decode_pointer(); 284 } else { 285 forwardee = _par_scan_state->copy_to_survivor_space(state, obj, m); 286 } 287 assert(forwardee != NULL, "forwardee should not be NULL"); 288 oopDesc::encode_store_heap_oop(p, forwardee); 289 if (do_mark_object != G1MarkNone && forwardee != obj) { 290 // If the object is self-forwarded we don't need to explicitly 291 // mark it, the evacuation failure protocol will do so. 292 mark_forwarded_object(obj, forwardee); 293 } 294 295 if (barrier == G1BarrierKlass) { 296 do_klass_barrier(p, forwardee); 297 } 298 } else { 299 if (state.is_humongous()) { 300 _g1->set_humongous_is_live(obj); 301 } 302 303 if (use_ext && state.is_ext()) { 304 _par_scan_state->do_oop_ext(p); 305 } 306 // The object is not in collection set. If we're a root scanning 307 // closure during an initial mark pause then attempt to mark the object. 308 if (do_mark_object == G1MarkFromRoot) { 309 mark_object(obj); 310 } 311 } 312 } 313 314 #endif // SHARE_VM_GC_G1_G1OOPCLOSURES_INLINE_HPP