1 /*
   2  * Copyright (c) 2001, 2020, 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_GC_G1_G1OOPCLOSURES_INLINE_HPP
  26 #define SHARE_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/heapRegion.inline.hpp"
  34 #include "gc/g1/heapRegionRemSet.hpp"
  35 #include "memory/iterator.inline.hpp"
  36 #include "oops/access.inline.hpp"
  37 #include "oops/compressedOops.inline.hpp"
  38 #include "oops/oopsHierarchy.hpp"
  39 #include "oops/oop.inline.hpp"
  40 #include "runtime/prefetch.inline.hpp"
  41 #include "utilities/align.hpp"
  42 
  43 template <class T>
  44 inline void G1ScanClosureBase::prefetch_and_push(T* p, const oop obj) {
  45   // We're not going to even bother checking whether the object is
  46   // already forwarded or not, as this usually causes an immediate
  47   // stall. We'll try to prefetch the object (for write, given that
  48   // we might need to install the forwarding reference) and we'll
  49   // get back to it when pop it from the queue
  50   Prefetch::write(obj->mark_addr_raw(), 0);
  51   Prefetch::read(obj->mark_addr_raw(), (HeapWordSize*2));
  52 
  53   // slightly paranoid test; I'm trying to catch potential
  54   // problems before we go into push_on_queue to know where the
  55   // problem is coming from
  56   assert((obj == RawAccess<>::oop_load(p)) ||
  57          (obj->is_forwarded() &&
  58          obj->forwardee() == RawAccess<>::oop_load(p)),
  59          "p should still be pointing to obj or to its forwardee");
  60 
  61   _par_scan_state->push_on_queue(ScannerTask(p));
  62 }
  63 
  64 template <class T>
  65 inline void G1ScanClosureBase::handle_non_cset_obj_common(G1HeapRegionAttr const region_attr, T* p, oop const obj) {
  66   if (region_attr.is_humongous()) {
  67     _g1h->set_humongous_is_live(obj);
  68   } else if (region_attr.is_optional()) {
  69     _par_scan_state->remember_reference_into_optional_region(p);
  70   }
  71 }
  72 
  73 inline void G1ScanClosureBase::trim_queue_partially() {
  74   _par_scan_state->trim_queue_partially();
  75 }
  76 
  77 template <class T>
  78 inline void G1ScanEvacuatedObjClosure::do_oop_work(T* p) {
  79   T heap_oop = RawAccess<>::oop_load(p);
  80 
  81   if (CompressedOops::is_null(heap_oop)) {
  82     return;
  83   }
  84   oop obj = CompressedOops::decode_not_null(heap_oop);
  85   const G1HeapRegionAttr region_attr = _g1h->region_attr(obj);
  86   if (region_attr.is_in_cset()) {
  87     prefetch_and_push(p, obj);
  88   } else if (!HeapRegion::is_in_same_region(p, obj)) {
  89     handle_non_cset_obj_common(region_attr, p, obj);
  90     assert(_scanning_in_young != Uninitialized, "Scan location has not been initialized.");
  91     if (_scanning_in_young == True) {
  92       return;
  93     }
  94     _par_scan_state->enqueue_card_if_tracked(region_attr, p, obj);
  95   }
  96 }
  97 
  98 template <class T>
  99 inline void G1CMOopClosure::do_oop_work(T* p) {
 100   _task->deal_with_reference(p);
 101 }
 102 
 103 template <class T>
 104 inline void G1RootRegionScanClosure::do_oop_work(T* p) {
 105   T heap_oop = RawAccess<MO_VOLATILE>::oop_load(p);
 106   if (CompressedOops::is_null(heap_oop)) {
 107     return;
 108   }
 109   oop obj = CompressedOops::decode_not_null(heap_oop);
 110   _cm->mark_in_next_bitmap(_worker_id, obj);
 111 }
 112 
 113 template <class T>
 114 inline static void check_obj_during_refinement(T* p, oop const obj) {
 115 #ifdef ASSERT
 116   G1CollectedHeap* g1h = G1CollectedHeap::heap();
 117   // can't do because of races
 118   // assert(oopDesc::is_oop_or_null(obj), "expected an oop");
 119   assert(is_object_aligned(obj), "oop must be aligned");
 120   assert(g1h->is_in_reserved(obj), "oop must be in reserved");
 121 
 122   HeapRegion* from = g1h->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           g1h->heap_region_containing(p)->is_humongous() &&
 128           from->humongous_start_region() == g1h->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_work(T* p) {
 136   T o = RawAccess<MO_VOLATILE>::oop_load(p);
 137   if (CompressedOops::is_null(o)) {
 138     return;
 139   }
 140   oop obj = CompressedOops::decode_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     // Also 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 we never
 151     // try to either evacuate or eager reclaim humonguous arrays of j.l.O.
 152     return;
 153   }
 154 
 155   HeapRegionRemSet* to_rem_set = _g1h->heap_region_containing(obj)->rem_set();
 156 
 157   assert(to_rem_set != NULL, "Need per-region 'into' remsets.");
 158   if (to_rem_set->is_tracked()) {
 159     to_rem_set->add_reference(p, _worker_id);
 160   }
 161 }
 162 
 163 template <class T>
 164 inline void G1ScanCardClosure::do_oop_work(T* p) {
 165   T o = RawAccess<>::oop_load(p);
 166   if (CompressedOops::is_null(o)) {
 167     return;
 168   }
 169   oop obj = CompressedOops::decode_not_null(o);
 170 
 171   check_obj_during_refinement(p, obj);
 172 
 173   assert(!_g1h->is_in_cset((HeapWord*)p),
 174          "Oop originates from " PTR_FORMAT " (region: %u) which is in the collection set.",
 175          p2i(p), _g1h->addr_to_region((HeapWord*)p));
 176 
 177   const G1HeapRegionAttr region_attr = _g1h->region_attr(obj);
 178   if (region_attr.is_in_cset()) {
 179     // Since the source is always from outside the collection set, here we implicitly know
 180     // that this is a cross-region reference too.
 181     prefetch_and_push(p, obj);
 182   } else if (!HeapRegion::is_in_same_region(p, obj)) {
 183     handle_non_cset_obj_common(region_attr, p, obj);
 184     _par_scan_state->enqueue_card_if_tracked(region_attr, p, obj);
 185   }
 186 }
 187 
 188 template <class T>
 189 inline void G1ScanRSForOptionalClosure::do_oop_work(T* p) {
 190   const G1HeapRegionAttr region_attr = _g1h->region_attr(p);
 191   // Entries in the optional collection set may start to originate from the collection
 192   // set after one or more increments. In this case, previously optional regions
 193   // became actual collection set regions. Filter them out here.
 194   if (region_attr.is_in_cset()) {
 195     return;
 196   }
 197   _scan_cl->do_oop_work(p);
 198   _scan_cl->trim_queue_partially();
 199 }
 200 
 201 void G1ParCopyHelper::do_cld_barrier(oop new_obj) {
 202   if (_g1h->heap_region_containing(new_obj)->is_young()) {
 203     _scanned_cld->record_modified_oops();
 204   }
 205 }
 206 
 207 void G1ParCopyHelper::mark_object(oop obj) {
 208   assert(!_g1h->heap_region_containing(obj)->in_collection_set(), "should not mark objects in the CSet");
 209 
 210   // We know that the object is not moving so it's safe to read its size.
 211   _cm->mark_in_next_bitmap(_worker_id, obj);
 212 }
 213 
 214 void G1ParCopyHelper::trim_queue_partially() {
 215   _par_scan_state->trim_queue_partially();
 216 }
 217 
 218 template <G1Barrier barrier, G1Mark do_mark_object>
 219 template <class T>
 220 void G1ParCopyClosure<barrier, do_mark_object>::do_oop_work(T* p) {
 221   T heap_oop = RawAccess<>::oop_load(p);
 222 
 223   if (CompressedOops::is_null(heap_oop)) {
 224     return;
 225   }
 226 
 227   oop obj = CompressedOops::decode_not_null(heap_oop);
 228 
 229   assert(_worker_id == _par_scan_state->worker_id(), "sanity");
 230 
 231   const G1HeapRegionAttr state = _g1h->region_attr(obj);
 232   if (state.is_in_cset()) {
 233     oop forwardee;
 234     markWord m = obj->mark_raw();
 235     if (m.is_marked()) {
 236       forwardee = (oop) m.decode_pointer();
 237     } else {
 238       forwardee = _par_scan_state->copy_to_survivor_space(state, obj, m);
 239     }
 240     assert(forwardee != NULL, "forwardee should not be NULL");
 241     RawAccess<IS_NOT_NULL>::oop_store(p, forwardee);
 242 
 243     if (barrier == G1BarrierCLD) {
 244       do_cld_barrier(forwardee);
 245     }
 246   } else {
 247     if (state.is_humongous()) {
 248       _g1h->set_humongous_is_live(obj);
 249     } else if ((barrier != G1BarrierNoOptRoots) && state.is_optional()) {
 250       _par_scan_state->remember_root_into_optional_region(p);
 251     }
 252 
 253     // The object is not in collection set. If we're a root scanning
 254     // closure during an initial mark pause then attempt to mark the object.
 255     if (do_mark_object == G1MarkFromRoot) {
 256       mark_object(obj);
 257     }
 258   }
 259   trim_queue_partially();
 260 }
 261 
 262 template <class T> void G1RebuildRemSetClosure::do_oop_work(T* p) {
 263   oop const obj = RawAccess<MO_VOLATILE>::oop_load(p);
 264   if (obj == NULL) {
 265     return;
 266   }
 267 
 268   if (HeapRegion::is_in_same_region(p, obj)) {
 269     return;
 270   }
 271 
 272   HeapRegion* to = _g1h->heap_region_containing(obj);
 273   HeapRegionRemSet* rem_set = to->rem_set();
 274   rem_set->add_reference(p, _worker_id);
 275 }
 276 
 277 #endif // SHARE_GC_G1_G1OOPCLOSURES_INLINE_HPP