1 /*
   2  * Copyright (c) 2001, 2015, 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/concurrentMark.inline.hpp"
  29 #include "gc/g1/g1CollectedHeap.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_nv(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       }
  94       _par_scan_state->update_rs(_from, p);
  95     }
  96   }
  97 }
  98 
  99 template <class T>
 100 inline void G1ParPushHeapRSClosure::do_oop_nv(T* p) {
 101   T heap_oop = oopDesc::load_heap_oop(p);
 102 
 103   if (!oopDesc::is_null(heap_oop)) {
 104     oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
 105     if (_g1->is_in_cset_or_humongous(obj)) {
 106       Prefetch::write(obj->mark_addr(), 0);
 107       Prefetch::read(obj->mark_addr(), (HeapWordSize*2));
 108 
 109       // Place on the references queue
 110       _par_scan_state->push_on_queue(p);
 111     } else {
 112       assert(!_g1->obj_in_cs(obj), "checking");
 113     }
 114   }
 115 }
 116 
 117 template <class T>
 118 inline void G1CMOopClosure::do_oop_nv(T* p) {
 119   oop obj = oopDesc::load_decode_heap_oop(p);
 120   _task->deal_with_reference(obj);
 121 }
 122 
 123 template <class T>
 124 inline void G1RootRegionScanClosure::do_oop_nv(T* p) {
 125   T heap_oop = oopDesc::load_heap_oop(p);
 126   if (!oopDesc::is_null(heap_oop)) {
 127     oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
 128     HeapRegion* hr = _g1h->heap_region_containing((HeapWord*) obj);
 129     _cm->grayRoot(obj, obj->size(), _worker_id, hr);
 130   }
 131 }
 132 
 133 template <class T>
 134 inline void G1Mux2Closure::do_oop_nv(T* p) {
 135   // Apply first closure; then apply the second.
 136   _c1->do_oop(p);
 137   _c2->do_oop(p);
 138 }
 139 
 140 template <class T>
 141 inline void G1TriggerClosure::do_oop_nv(T* p) {
 142   // Record that this closure was actually applied (triggered).
 143   _triggered = true;
 144 }
 145 
 146 template <class T>
 147 inline void G1InvokeIfNotTriggeredClosure::do_oop_nv(T* p) {
 148   if (!_trigger_cl->triggered()) {
 149     _oop_cl->do_oop(p);
 150   }
 151 }
 152 
 153 template <class T>
 154 inline void G1UpdateRSOrPushRefOopClosure::do_oop_nv(T* p) {
 155   oop obj = oopDesc::load_decode_heap_oop(p);
 156   if (obj == NULL) {
 157     return;
 158   }
 159 
 160 #ifdef ASSERT
 161   // can't do because of races
 162   // assert(obj == NULL || obj->is_oop(), "expected an oop");
 163 
 164   // Do the safe subset of is_oop
 165 #ifdef CHECK_UNHANDLED_OOPS
 166   oopDesc* o = obj.obj();
 167 #else
 168   oopDesc* o = obj;
 169 #endif // CHECK_UNHANDLED_OOPS
 170   assert((intptr_t)o % MinObjAlignmentInBytes == 0, "not oop aligned");
 171   assert(_g1->is_in_reserved(obj), "must be in heap");
 172 #endif // ASSERT
 173 
 174   assert(_from != NULL, "from region must be non-NULL");
 175   assert(_from->is_in_reserved(p), "p is not in from");
 176 
 177   HeapRegion* to = _g1->heap_region_containing(obj);
 178   if (_from == to) {
 179     // Normally this closure should only be called with cross-region references.
 180     // But since Java threads are manipulating the references concurrently and we
 181     // reload the values things may have changed.
 182     return;
 183   }
 184 
 185   // The _record_refs_into_cset flag is true during the RSet
 186   // updating part of an evacuation pause. It is false at all
 187   // other times:
 188   //  * rebuilding the remembered sets after a full GC
 189   //  * during concurrent refinement.
 190   //  * updating the remembered sets of regions in the collection
 191   //    set in the event of an evacuation failure (when deferred
 192   //    updates are enabled).
 193 
 194   if (_record_refs_into_cset && to->in_collection_set()) {
 195     // We are recording references that point into the collection
 196     // set and this particular reference does exactly that...
 197     // If the referenced object has already been forwarded
 198     // to itself, we are handling an evacuation failure and
 199     // we have already visited/tried to copy this object
 200     // there is no need to retry.
 201     if (!self_forwarded(obj)) {
 202       assert(_push_ref_cl != NULL, "should not be null");
 203       // Push the reference in the refs queue of the G1ParScanThreadState
 204       // instance for this worker thread.
 205       _push_ref_cl->do_oop(p);
 206     }
 207 
 208     // Deferred updates to the CSet are either discarded (in the normal case),
 209     // or processed (if an evacuation failure occurs) at the end
 210     // of the collection.
 211     // See G1RemSet::cleanup_after_oops_into_collection_set_do().
 212   } else {
 213     // We either don't care about pushing references that point into the
 214     // collection set (i.e. we're not during an evacuation pause) _or_
 215     // the reference doesn't point into the collection set. Either way
 216     // we add the reference directly to the RSet of the region containing
 217     // the referenced object.
 218     assert(to->rem_set() != NULL, "Need per-region 'into' remsets.");
 219     to->rem_set()->add_reference(p, _worker_i);
 220   }
 221 }
 222 
 223 template <class T>
 224 void G1ParCopyHelper::do_klass_barrier(T* p, oop new_obj) {
 225   if (_g1->heap_region_containing_raw(new_obj)->is_young()) {
 226     _scanned_klass->record_modified_oops();
 227   }
 228 }
 229 
 230 void G1ParCopyHelper::mark_object(oop obj) {
 231   assert(!_g1->heap_region_containing(obj)->in_collection_set(), "should not mark objects in the CSet");
 232 
 233   // We know that the object is not moving so it's safe to read its size.
 234   _cm->grayRoot(obj, (size_t) obj->size(), _worker_id);
 235 }
 236 
 237 void G1ParCopyHelper::mark_forwarded_object(oop from_obj, oop to_obj) {
 238   assert(from_obj->is_forwarded(), "from obj should be forwarded");
 239   assert(from_obj->forwardee() == to_obj, "to obj should be the forwardee");
 240   assert(from_obj != to_obj, "should not be self-forwarded");
 241 
 242   assert(_g1->heap_region_containing(from_obj)->in_collection_set(), "from obj should be in the CSet");
 243   assert(!_g1->heap_region_containing(to_obj)->in_collection_set(), "should not mark objects in the CSet");
 244 
 245   // The object might be in the process of being copied by another
 246   // worker so we cannot trust that its to-space image is
 247   // well-formed. So we have to read its size from its from-space
 248   // image which we know should not be changing.
 249   _cm->grayRoot(to_obj, (size_t) from_obj->size(), _worker_id);
 250 }
 251 
 252 template <G1Barrier barrier, G1Mark do_mark_object>
 253 template <class T>
 254 void G1ParCopyClosure<barrier, do_mark_object>::do_oop_work(T* p) {
 255   T heap_oop = oopDesc::load_heap_oop(p);
 256 
 257   if (oopDesc::is_null(heap_oop)) {
 258     return;
 259   }
 260 
 261   oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
 262 
 263   assert(_worker_id == _par_scan_state->worker_id(), "sanity");
 264 
 265   const InCSetState state = _g1->in_cset_state(obj);
 266   if (state.is_in_cset()) {
 267     oop forwardee;
 268     markOop m = obj->mark();
 269     if (m->is_marked()) {
 270       forwardee = (oop) m->decode_pointer();
 271     } else {
 272       forwardee = _par_scan_state->copy_to_survivor_space(state, obj, m);
 273     }
 274     assert(forwardee != NULL, "forwardee should not be NULL");
 275     oopDesc::encode_store_heap_oop(p, forwardee);
 276     if (do_mark_object != G1MarkNone && forwardee != obj) {
 277       // If the object is self-forwarded we don't need to explicitly
 278       // mark it, the evacuation failure protocol will do so.
 279       mark_forwarded_object(obj, forwardee);
 280     }
 281 
 282     if (barrier == G1BarrierKlass) {
 283       do_klass_barrier(p, forwardee);
 284     }
 285   } else {
 286     if (state.is_humongous()) {
 287       _g1->set_humongous_is_live(obj);
 288     }
 289     // The object is not in collection set. If we're a root scanning
 290     // closure during an initial mark pause then attempt to mark the object.
 291     if (do_mark_object == G1MarkFromRoot) {
 292       mark_object(obj);
 293     }
 294   }
 295 }
 296 
 297 #endif // SHARE_VM_GC_G1_G1OOPCLOSURES_INLINE_HPP