1 /*
   2  * Copyright (c) 2002, 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_PARALLEL_PSSCAVENGE_INLINE_HPP
  26 #define SHARE_VM_GC_PARALLEL_PSSCAVENGE_INLINE_HPP
  27 
  28 #include "gc/parallel/cardTableExtension.hpp"
  29 #include "gc/parallel/parallelScavengeHeap.hpp"
  30 #include "gc/parallel/psPromotionManager.inline.hpp"
  31 #include "gc/parallel/psScavenge.hpp"
  32 #include "logging/log.hpp"
  33 #include "memory/iterator.hpp"

  34 #include "utilities/globalDefinitions.hpp"
  35 
  36 inline void PSScavenge::save_to_space_top_before_gc() {
  37   ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
  38   _to_space_top_before_gc = heap->young_gen()->to_space()->top();
  39 }
  40 
  41 template <class T> inline bool PSScavenge::should_scavenge(T* p) {
  42   T heap_oop = oopDesc::load_heap_oop(p);
  43   return PSScavenge::is_obj_in_young(heap_oop);
  44 }
  45 
  46 template <class T>
  47 inline bool PSScavenge::should_scavenge(T* p, MutableSpace* to_space) {
  48   if (should_scavenge(p)) {
  49     oop obj = oopDesc::load_decode_heap_oop_not_null(p);
  50     // Skip objects copied to to_space since the scavenge started.
  51     HeapWord* const addr = (HeapWord*)obj;
  52     return addr < to_space_top_before_gc() || addr >= to_space->end();
  53   }
  54   return false;
  55 }
  56 
  57 template <class T>
  58 inline bool PSScavenge::should_scavenge(T* p, bool check_to_space) {
  59   if (check_to_space) {
  60     ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
  61     return should_scavenge(p, heap->young_gen()->to_space());
  62   }
  63   return should_scavenge(p);
  64 }
  65 
  66 template<bool promote_immediately>
  67 class PSRootsClosure: public OopClosure {
  68  private:
  69   PSPromotionManager* _promotion_manager;
  70 
  71  protected:
  72   template <class T> void do_oop_work(T *p) {
  73     if (PSScavenge::should_scavenge(p)) {
  74       // We never card mark roots, maybe call a func without test?
  75       _promotion_manager->copy_and_push_safe_barrier<T, promote_immediately>(p);
  76     }
  77   }
  78  public:
  79   PSRootsClosure(PSPromotionManager* pm) : _promotion_manager(pm) { }
  80   void do_oop(oop* p)       { PSRootsClosure::do_oop_work(p); }
  81   void do_oop(narrowOop* p) { PSRootsClosure::do_oop_work(p); }
  82 };
  83 
  84 typedef PSRootsClosure</*promote_immediately=*/false> PSScavengeRootsClosure;
  85 typedef PSRootsClosure</*promote_immediately=*/true> PSPromoteRootsClosure;
  86 
  87 // Scavenges a single oop in a Klass.
  88 class PSScavengeFromKlassClosure: public OopClosure {
  89  private:
  90   PSPromotionManager* _pm;
  91   // Used to redirty a scanned klass if it has oops
  92   // pointing to the young generation after being scanned.
  93   Klass*             _scanned_klass;
  94  public:
  95   PSScavengeFromKlassClosure(PSPromotionManager* pm) : _pm(pm), _scanned_klass(NULL) { }
  96   void do_oop(narrowOop* p) { ShouldNotReachHere(); }
  97   void do_oop(oop* p)       {
  98     ParallelScavengeHeap* psh = ParallelScavengeHeap::heap();
  99     assert(!psh->is_in_reserved(p), "GC barrier needed");
 100     if (PSScavenge::should_scavenge(p)) {
 101       assert(PSScavenge::should_scavenge(p, true), "revisiting object?");
 102 
 103       oop o = *p;
 104       oop new_obj;
 105       if (o->is_forwarded()) {
 106         new_obj = o->forwardee();
 107       } else {
 108         new_obj = _pm->copy_to_survivor_space</*promote_immediately=*/false>(o);
 109       }
 110       oopDesc::encode_store_heap_oop_not_null(p, new_obj);
 111 
 112       if (PSScavenge::is_obj_in_young(new_obj)) {
 113         do_klass_barrier();
 114       }
 115     }
 116   }
 117 
 118   void set_scanned_klass(Klass* klass) {
 119     assert(_scanned_klass == NULL || klass == NULL, "Should always only handling one klass at a time");
 120     _scanned_klass = klass;
 121   }
 122 
 123  private:
 124   void do_klass_barrier() {
 125     assert(_scanned_klass != NULL, "Should not be called without having a scanned klass");
 126     _scanned_klass->record_modified_oops();
 127   }
 128 
 129 };
 130 
 131 // Scavenges the oop in a Klass.
 132 class PSScavengeKlassClosure: public KlassClosure {
 133  private:
 134   PSScavengeFromKlassClosure _oop_closure;
 135  protected:
 136  public:
 137   PSScavengeKlassClosure(PSPromotionManager* pm) : _oop_closure(pm) { }
 138   void do_klass(Klass* klass) {
 139     // If the klass has not been dirtied we know that there's
 140     // no references into  the young gen and we can skip it.
 141 
 142     NOT_PRODUCT(ResourceMark rm);
 143     log_develop_trace(gc, scavenge)("PSScavengeKlassClosure::do_klass " PTR_FORMAT ", %s, dirty: %s",
 144                                     p2i(klass),
 145                                     klass->external_name(),
 146                                     klass->has_modified_oops() ? "true" : "false");
 147 
 148     if (klass->has_modified_oops()) {
 149       // Clean the klass since we're going to scavenge all the metadata.
 150       klass->clear_modified_oops();
 151 
 152       // Setup the promotion manager to redirty this klass
 153       // if references are left in the young gen.
 154       _oop_closure.set_scanned_klass(klass);
 155 
 156       klass->oops_do(&_oop_closure);
 157 
 158       _oop_closure.set_scanned_klass(NULL);
 159     }
 160   }
 161 };
 162 
 163 #endif // SHARE_VM_GC_PARALLEL_PSSCAVENGE_INLINE_HPP
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