xref: /openjdk10/hotspot/src/share/vm/gc/parallel/psScavenge.inline.hpp

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#ifndef SHARE_VM_GC_PARALLEL_PSSCAVENGE_INLINE_HPP
#define SHARE_VM_GC_PARALLEL_PSSCAVENGE_INLINE_HPP

#include "gc/parallel/cardTableExtension.hpp"
#include "gc/parallel/parallelScavengeHeap.hpp"
#include "gc/parallel/psPromotionManager.inline.hpp"
#include "gc/parallel/psScavenge.hpp"
#include "logging/log.hpp"
#include "memory/iterator.hpp"
#include "utilities/globalDefinitions.hpp"

inline void PSScavenge::save_to_space_top_before_gc() {
  ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
  _to_space_top_before_gc = heap->young_gen()->to_space()->top();
}

template <class T> inline bool PSScavenge::should_scavenge(T* p) {
  T heap_oop = oopDesc::load_heap_oop(p);
  return PSScavenge::is_obj_in_young(heap_oop);
}

template <class T>
inline bool PSScavenge::should_scavenge(T* p, MutableSpace* to_space) {
  if (should_scavenge(p)) {
    oop obj = oopDesc::load_decode_heap_oop_not_null(p);
    // Skip objects copied to to_space since the scavenge started.
    HeapWord* const addr = (HeapWord*)obj;
    return addr < to_space_top_before_gc() || addr >= to_space->end();
  }
  return false;
}

template <class T>
inline bool PSScavenge::should_scavenge(T* p, bool check_to_space) {
  if (check_to_space) {
    ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
    return should_scavenge(p, heap->young_gen()->to_space());
  }
  return should_scavenge(p);
}

template<bool promote_immediately>
class PSRootsClosure: public OopClosure {
 private:
  PSPromotionManager* _promotion_manager;

 protected:
  template <class T> void do_oop_work(T *p) {
    if (PSScavenge::should_scavenge(p)) {
      // We never card mark roots, maybe call a func without test?
      _promotion_manager->copy_and_push_safe_barrier<T, promote_immediately>(p);
    }
  }
 public:
  PSRootsClosure(PSPromotionManager* pm) : _promotion_manager(pm) { }
  void do_oop(oop* p)       { PSRootsClosure::do_oop_work(p); }
  void do_oop(narrowOop* p) { PSRootsClosure::do_oop_work(p); }
};

typedef PSRootsClosure</*promote_immediately=*/false> PSScavengeRootsClosure;
typedef PSRootsClosure</*promote_immediately=*/true> PSPromoteRootsClosure;

// Scavenges a single oop in a Klass.
class PSScavengeFromKlassClosure: public OopClosure {
 private:
  PSPromotionManager* _pm;
  // Used to redirty a scanned klass if it has oops
  // pointing to the young generation after being scanned.
  Klass*             _scanned_klass;
 public:
  PSScavengeFromKlassClosure(PSPromotionManager* pm) : _pm(pm), _scanned_klass(NULL) { }
  void do_oop(narrowOop* p) { ShouldNotReachHere(); }
  void do_oop(oop* p)       {
    ParallelScavengeHeap* psh = ParallelScavengeHeap::heap();
    assert(!psh->is_in_reserved(p), "GC barrier needed");
    if (PSScavenge::should_scavenge(p)) {
      assert(PSScavenge::should_scavenge(p, true), "revisiting object?");

      oop o = *p;
      oop new_obj;
      if (o->is_forwarded()) {
        new_obj = o->forwardee();
      } else {
        new_obj = _pm->copy_to_survivor_space</*promote_immediately=*/false>(o);
      }
      oopDesc::encode_store_heap_oop_not_null(p, new_obj);

      if (PSScavenge::is_obj_in_young(new_obj)) {
        do_klass_barrier();
      }
    }
  }

  void set_scanned_klass(Klass* klass) {
    assert(_scanned_klass == NULL || klass == NULL, "Should always only handling one klass at a time");
    _scanned_klass = klass;
  }

 private:
  void do_klass_barrier() {
    assert(_scanned_klass != NULL, "Should not be called without having a scanned klass");
    _scanned_klass->record_modified_oops();
  }

};

// Scavenges the oop in a Klass.
class PSScavengeKlassClosure: public KlassClosure {
 private:
  PSScavengeFromKlassClosure _oop_closure;
 protected:
 public:
  PSScavengeKlassClosure(PSPromotionManager* pm) : _oop_closure(pm) { }
  void do_klass(Klass* klass) {
    // If the klass has not been dirtied we know that there's
    // no references into  the young gen and we can skip it.

    NOT_PRODUCT(ResourceMark rm);
    log_develop_trace(gc, scavenge)("PSScavengeKlassClosure::do_klass " PTR_FORMAT ", %s, dirty: %s",
                                    p2i(klass),
                                    klass->external_name(),
                                    klass->has_modified_oops() ? "true" : "false");

    if (klass->has_modified_oops()) {
      // Clean the klass since we're going to scavenge all the metadata.
      klass->clear_modified_oops();

      // Setup the promotion manager to redirty this klass
      // if references are left in the young gen.
      _oop_closure.set_scanned_klass(klass);

      klass->oops_do(&_oop_closure);

      _oop_closure.set_scanned_klass(NULL);
    }
  }
};

#endif // SHARE_VM_GC_PARALLEL_PSSCAVENGE_INLINE_HPP