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 /*
  40  * This really ought to be an inline function, but apparently the C++
  41  * compiler sometimes sees fit to ignore inline declarations.  Sigh.
  42  */
  43 
  44 template <class T>
  45 inline void FilterIntoCSClosure::do_oop_work(T* p) {
  46   T heap_oop = oopDesc::load_heap_oop(p);
  47   if (!oopDesc::is_null(heap_oop) &&
  48       _g1->is_in_cset_or_humongous(oopDesc::decode_heap_oop_not_null(heap_oop))) {
  49     _oc->do_oop(p);
  50   }
  51 }
  52 
  53 template <class T>
  54 inline void FilterOutOfRegionClosure::do_oop_nv(T* p) {
  55   T heap_oop = oopDesc::load_heap_oop(p);
  56   if (!oopDesc::is_null(heap_oop)) {
  57     HeapWord* obj_hw = (HeapWord*)oopDesc::decode_heap_oop_not_null(heap_oop);
  58     if (obj_hw < _r_bottom || obj_hw >= _r_end) {
  59       _oc->do_oop(p);
  60     }
  61   }
  62 }
  63 
  64 // This closure is applied to the fields of the objects that have just been copied.
  65 template <class T>
  66 inline void G1ParScanClosure::do_oop_nv(T* p) {
  67   T heap_oop = oopDesc::load_heap_oop(p);
  68 
  69   if (!oopDesc::is_null(heap_oop)) {
  70     oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
  71     const InCSetState state = _g1->in_cset_state(obj);
  72     if (state.is_in_cset()) {
  73       // We're not going to even bother checking whether the object is
  74       // already forwarded or not, as this usually causes an immediate
  75       // stall. We'll try to prefetch the object (for write, given that
  76       // we might need to install the forwarding reference) and we'll
  77       // get back to it when pop it from the queue
  78       Prefetch::write(obj->mark_addr(), 0);
  79       Prefetch::read(obj->mark_addr(), (HeapWordSize*2));
  80 
  81       // slightly paranoid test; I'm trying to catch potential
  82       // problems before we go into push_on_queue to know where the
  83       // problem is coming from
  84       assert((obj == oopDesc::load_decode_heap_oop(p)) ||
  85              (obj->is_forwarded() &&
  86                  obj->forwardee() == oopDesc::load_decode_heap_oop(p)),
  87              "p should still be pointing to obj or to its forwardee");
  88 
  89       _par_scan_state->push_on_queue(p);
  90     } else {
  91       if (state.is_humongous()) {
  92         _g1->set_humongous_is_live(obj);
  93       } else if (state.is_ext()) {
  94         _par_scan_state->do_oop_ext(p);
  95       }
  96       _par_scan_state->update_rs(_from, p, obj);
  97     }
  98   }
  99 }
 100 
 101 template <class T>
 102 inline void G1ParPushHeapRSClosure::do_oop_nv(T* p) {
 103   T heap_oop = oopDesc::load_heap_oop(p);
 104 
 105   if (!oopDesc::is_null(heap_oop)) {
 106     oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
 107     const InCSetState state = _g1->in_cset_state(obj);
 108     if (state.is_in_cset_or_humongous()) {
 109       Prefetch::write(obj->mark_addr(), 0);
 110       Prefetch::read(obj->mark_addr(), (HeapWordSize*2));
 111 
 112       // Place on the references queue
 113       _par_scan_state->push_on_queue(p);
 114     } else if (state.is_ext()) {
 115       _par_scan_state->do_oop_ext(p);
 116     } else {
 117       assert(!_g1->is_in_cset(obj), "checking");
 118     }
 119   }
 120 }
 121 
 122 template <class T>
 123 inline void G1CMOopClosure::do_oop_nv(T* p) {
 124   oop obj = oopDesc::load_decode_heap_oop(p);
 125   _task->deal_with_reference(obj);
 126 }
 127 
 128 template <class T>
 129 inline void G1RootRegionScanClosure::do_oop_nv(T* p) {
 130   T heap_oop = oopDesc::load_heap_oop(p);
 131   if (!oopDesc::is_null(heap_oop)) {
 132     oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
 133     HeapRegion* hr = _g1h->heap_region_containing((HeapWord*) obj);
 134     _cm->grayRoot(obj, hr);
 135   }
 136 }
 137 
 138 template <class T>
 139 inline void G1Mux2Closure::do_oop_work(T* p) {
 140   // Apply first closure; then apply the second.
 141   _c1->do_oop(p);
 142   _c2->do_oop(p);
 143 }
 144 void G1Mux2Closure::do_oop(oop* p)       { do_oop_work(p); }
 145 void G1Mux2Closure::do_oop(narrowOop* p) { do_oop_work(p); }
 146 
 147 template <class T>
 148 inline void G1TriggerClosure::do_oop_work(T* p) {
 149   // Record that this closure was actually applied (triggered).
 150   _triggered = true;
 151 }
 152 void G1TriggerClosure::do_oop(oop* p)       { do_oop_work(p); }
 153 void G1TriggerClosure::do_oop(narrowOop* p) { do_oop_work(p); }
 154 
 155 template <class T>
 156 inline void G1InvokeIfNotTriggeredClosure::do_oop_work(T* p) {
 157   if (!_trigger_cl->triggered()) {
 158     _oop_cl->do_oop(p);
 159   }
 160 }
 161 void G1InvokeIfNotTriggeredClosure::do_oop(oop* p)       { do_oop_work(p); }
 162 void G1InvokeIfNotTriggeredClosure::do_oop(narrowOop* p) { do_oop_work(p); }
 163 
 164 template <class T>
 165 inline void G1UpdateRSOrPushRefOopClosure::do_oop_work(T* p) {
 166   oop obj = oopDesc::load_decode_heap_oop(p);
 167   if (obj == NULL) {
 168     return;
 169   }
 170 
 171 #ifdef ASSERT
 172   // can't do because of races
 173   // assert(obj == NULL || obj->is_oop(), "expected an oop");
 174   assert(check_obj_alignment(obj), "not oop aligned");
 175   assert(_g1->is_in_reserved(obj), "must be in heap");
 176 #endif // ASSERT
 177 
 178   assert(_from != NULL, "from region must be non-NULL");
 179   assert(_from->is_in_reserved(p) ||
 180          (_from->is_humongous() &&
 181           _g1->heap_region_containing(p)->is_humongous() &&
 182           _from->humongous_start_region() == _g1->heap_region_containing(p)->humongous_start_region()),
 183          "p " PTR_FORMAT " is not in the same region %u or part of the correct humongous object starting at region %u.",
 184          p2i(p), _from->hrm_index(), _from->humongous_start_region()->hrm_index());
 185 
 186   HeapRegion* to = _g1->heap_region_containing(obj);
 187   if (_from == to) {
 188     // Normally this closure should only be called with cross-region references.
 189     // But since Java threads are manipulating the references concurrently and we
 190     // reload the values things may have changed.
 191     // Also this check lets slip through references from a humongous continues region
 192     // to its humongous start region, as they are in different regions, and adds a
 193     // remembered set entry. This is benign (apart from memory usage), as we never
 194     // try to either evacuate or eager reclaim these kind of regions.
 195     return;
 196   }
 197 
 198   // The _record_refs_into_cset flag is true during the RSet
 199   // updating part of an evacuation pause. It is false at all
 200   // other times:
 201   //  * rebuilding the remembered sets after a full GC
 202   //  * during concurrent refinement.
 203   //  * updating the remembered sets of regions in the collection
 204   //    set in the event of an evacuation failure (when deferred
 205   //    updates are enabled).
 206 
 207   if (_record_refs_into_cset && to->in_collection_set()) {
 208     // We are recording references that point into the collection
 209     // set and this particular reference does exactly that...
 210     // If the referenced object has already been forwarded
 211     // to itself, we are handling an evacuation failure and
 212     // we have already visited/tried to copy this object
 213     // there is no need to retry.
 214     if (!self_forwarded(obj)) {
 215       assert(_push_ref_cl != NULL, "should not be null");
 216       // Push the reference in the refs queue of the G1ParScanThreadState
 217       // instance for this worker thread.
 218       _push_ref_cl->do_oop(p);
 219     }
 220 
 221     // Deferred updates to the CSet are either discarded (in the normal case),
 222     // or processed (if an evacuation failure occurs) at the end
 223     // of the collection.
 224     // See G1RemSet::cleanup_after_oops_into_collection_set_do().
 225   } else {
 226     // We either don't care about pushing references that point into the
 227     // collection set (i.e. we're not during an evacuation pause) _or_
 228     // the reference doesn't point into the collection set. Either way
 229     // we add the reference directly to the RSet of the region containing
 230     // the referenced object.
 231     assert(to->rem_set() != NULL, "Need per-region 'into' remsets.");
 232     to->rem_set()->add_reference(p, _worker_i);
 233   }
 234 }
 235 void G1UpdateRSOrPushRefOopClosure::do_oop(oop* p)       { do_oop_work(p); }
 236 void G1UpdateRSOrPushRefOopClosure::do_oop(narrowOop* p) { do_oop_work(p); }
 237 
 238 template <class T>
 239 void G1ParCopyHelper::do_klass_barrier(T* p, oop new_obj) {
 240   if (_g1->heap_region_containing(new_obj)->is_young()) {
 241     _scanned_klass->record_modified_oops();
 242   }
 243 }
 244 
 245 void G1ParCopyHelper::mark_object(oop obj) {
 246   assert(!_g1->heap_region_containing(obj)->in_collection_set(), "should not mark objects in the CSet");
 247 
 248   // We know that the object is not moving so it's safe to read its size.
 249   _cm->grayRoot(obj);
 250 }
 251 
 252 void G1ParCopyHelper::mark_forwarded_object(oop from_obj, oop to_obj) {
 253   assert(from_obj->is_forwarded(), "from obj should be forwarded");
 254   assert(from_obj->forwardee() == to_obj, "to obj should be the forwardee");
 255   assert(from_obj != to_obj, "should not be self-forwarded");
 256 
 257   assert(_g1->heap_region_containing(from_obj)->in_collection_set(), "from obj should be in the CSet");
 258   assert(!_g1->heap_region_containing(to_obj)->in_collection_set(), "should not mark objects in the CSet");
 259 
 260   // The object might be in the process of being copied by another
 261   // worker so we cannot trust that its to-space image is
 262   // well-formed. So we have to read its size from its from-space
 263   // image which we know should not be changing.
 264   _cm->grayRoot(to_obj);
 265 }
 266 
 267 template <G1Barrier barrier, G1Mark do_mark_object, bool use_ext>
 268 template <class T>
 269 void G1ParCopyClosure<barrier, do_mark_object, use_ext>::do_oop_work(T* p) {
 270   T heap_oop = oopDesc::load_heap_oop(p);
 271 
 272   if (oopDesc::is_null(heap_oop)) {
 273     return;
 274   }
 275 
 276   oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
 277 
 278   assert(_worker_id == _par_scan_state->worker_id(), "sanity");
 279 
 280   const InCSetState state = _g1->in_cset_state(obj);
 281   if (state.is_in_cset()) {
 282     oop forwardee;
 283     markOop m = obj->mark();
 284     if (m->is_marked()) {
 285       forwardee = (oop) m->decode_pointer();
 286     } else {
 287       forwardee = _par_scan_state->copy_to_survivor_space(state, obj, m);
 288     }
 289     assert(forwardee != NULL, "forwardee should not be NULL");
 290     oopDesc::encode_store_heap_oop(p, forwardee);
 291     if (do_mark_object != G1MarkNone && forwardee != obj) {
 292       // If the object is self-forwarded we don't need to explicitly
 293       // mark it, the evacuation failure protocol will do so.
 294       mark_forwarded_object(obj, forwardee);
 295     }
 296 
 297     if (barrier == G1BarrierKlass) {
 298       do_klass_barrier(p, forwardee);
 299     }
 300   } else {
 301     if (state.is_humongous()) {
 302       _g1->set_humongous_is_live(obj);
 303     }
 304 
 305     if (use_ext && state.is_ext()) {
 306       _par_scan_state->do_oop_ext(p);
 307     }
 308     // The object is not in collection set. If we're a root scanning
 309     // closure during an initial mark pause then attempt to mark the object.
 310     if (do_mark_object == G1MarkFromRoot) {
 311       mark_object(obj);
 312     }
 313   }
 314 }
 315 
 316 #endif // SHARE_VM_GC_G1_G1OOPCLOSURES_INLINE_HPP