C++ G1CollectedHeap::heap_region_containing方法代码示例

  bool doHeapRegion(HeapRegion* r) {
    assert(r->in_collection_set(), "should only be called on elements of CS.");
    HeapRegionRemSet* hrrs = r->rem_set();
    if (hrrs->iter_is_complete()) return false; // All done.
    if (!_try_claimed && !hrrs->claim_iter()) return false;
    _g1h->push_dirty_cards_region(r);
    // If we didn't return above, then
    //   _try_claimed || r->claim_iter()
    // is true: either we're supposed to work on claimed-but-not-complete
    // regions, or we successfully claimed the region.
    HeapRegionRemSetIterator* iter = _g1h->rem_set_iterator(_worker_i);
    hrrs->init_iterator(iter);
    size_t card_index;

    // We claim cards in block so as to recude the contention. The block size is determined by
    // the G1RSetScanBlockSize parameter.
    size_t jump_to_card = hrrs->iter_claimed_next(_block_size);
    for (size_t current_card = 0; iter->has_next(card_index); current_card++) {
      if (current_card >= jump_to_card + _block_size) {
        jump_to_card = hrrs->iter_claimed_next(_block_size);
      }
      if (current_card < jump_to_card) continue;
      HeapWord* card_start = _g1h->bot_shared()->address_for_index(card_index);
#if 0
      gclog_or_tty->print("Rem set iteration yielded card [" PTR_FORMAT ", " PTR_FORMAT ").\n",
                          card_start, card_start + CardTableModRefBS::card_size_in_words);
#endif

      HeapRegion* card_region = _g1h->heap_region_containing(card_start);
      assert(card_region != NULL, "Yielding cards not in the heap?");
      _cards++;

      if (!card_region->is_on_dirty_cards_region_list()) {
        _g1h->push_dirty_cards_region(card_region);
      }

       // If the card is dirty, then we will scan it during updateRS.
      if (!card_region->in_collection_set() && !_ct_bs->is_card_dirty(card_index)) {
        // We make the card as "claimed" lazily (so races are possible but they're benign),
        // which reduces the number of duplicate scans (the rsets of the regions in the cset
        // can intersect).
        if (!_ct_bs->is_card_claimed(card_index)) {
          _ct_bs->set_card_claimed(card_index);
          scanCard(card_index, card_region);
        }
      }
    }
    if (!_try_claimed) {
      hrrs->set_iter_complete();
    }
    return false;
  }

  bool doHeapRegion(HeapRegion* r) {
    assert(r->in_collection_set(), "should only be called on elements of CS.");
    HeapRegionRemSet* hrrs = r->rem_set();
    if (hrrs->iter_is_complete()) return false; // All done.
    if (!_try_claimed && !hrrs->claim_iter()) return false;
    // If we ever free the collection set concurrently, we should also
    // clear the card table concurrently therefore we won't need to
    // add regions of the collection set to the dirty cards region.
    _g1h->push_dirty_cards_region(r);
    // If we didn't return above, then
    //   _try_claimed || r->claim_iter()
    // is true: either we're supposed to work on claimed-but-not-complete
    // regions, or we successfully claimed the region.

    HeapRegionRemSetIterator iter(hrrs);
    size_t card_index;

    // We claim cards in block so as to reduce the contention. The block size is determined by
    // the G1RSetScanBlockSize parameter.
    size_t jump_to_card = hrrs->iter_claimed_next(_block_size);
    for (size_t current_card = 0; iter.has_next(card_index); current_card++) {
      if (current_card >= jump_to_card + _block_size) {
        jump_to_card = hrrs->iter_claimed_next(_block_size);
      }
      if (current_card < jump_to_card) continue;
      HeapWord* card_start = _g1h->bot_shared()->address_for_index(card_index);
#if 0
      gclog_or_tty->print("Rem set iteration yielded card [" PTR_FORMAT ", " PTR_FORMAT ").\n",
                          card_start, card_start + CardTableModRefBS::card_size_in_words);
#endif

      HeapRegion* card_region = _g1h->heap_region_containing(card_start);
      _cards++;

      if (!card_region->is_on_dirty_cards_region_list()) {
        _g1h->push_dirty_cards_region(card_region);
      }

      // If the card is dirty, then we will scan it during updateRS.
      if (!card_region->in_collection_set() &&
          !_ct_bs->is_card_dirty(card_index)) {
        scanCard(card_index, card_region);
      }
    }
    if (!_try_claimed) {
      // Scan the strong code root list attached to the current region
      scan_strong_code_roots(r);

      hrrs->set_iter_complete();
    }
    return false;
  }

  bool do_card_ptr(jbyte* card_ptr, int worker_i) {
    // Construct the region representing the card.
    HeapWord* start = _ct_bs->addr_for(card_ptr);
    // And find the region containing it.
    HeapRegion* r = _g1->heap_region_containing(start);
    assert(r != NULL, "unexpected null");

    // Scan oops in the card looking for references into the collection set
    HeapWord* end   = _ct_bs->addr_for(card_ptr + 1);
    MemRegion scanRegion(start, end);

    UpdateRSetImmediate update_rs_cl(_g1->g1_rem_set());
    FilterIntoCSClosure update_rs_cset_oop_cl(NULL, _g1, &update_rs_cl);
    FilterOutOfRegionClosure filter_then_update_rs_cset_oop_cl(r, &update_rs_cset_oop_cl);

    // We can pass false as the "filter_young" parameter here as:
    // * we should be in a STW pause,
    // * the DCQS to which this closure is applied is used to hold
    //   references that point into the collection set from the prior
    //   RSet updating,
    // * the post-write barrier shouldn't be logging updates to young
    //   regions (but there is a situation where this can happen - see
    //   the comment in G1RemSet::concurrentRefineOneCard below -
    //   that should not be applicable here), and
    // * during actual RSet updating, the filtering of cards in young
    //   regions in HeapRegion::oops_on_card_seq_iterate_careful is
    //   employed.
    // As a result, when this closure is applied to "refs into cset"
    // DCQS, we shouldn't see any cards in young regions.
    update_rs_cl.set_region(r);
    HeapWord* stop_point =
      r->oops_on_card_seq_iterate_careful(scanRegion,
                                        &filter_then_update_rs_cset_oop_cl,
                                        false /* filter_young */);

    // Since this is performed in the event of an evacuation failure, we
    // we shouldn't see a non-null stop point
    assert(stop_point == NULL, "saw an unallocated region");
    return true;
  }

  template <class T> void do_oop_work(T* p) {
    assert(_containing_obj != NULL, "Precondition");
    assert(!_g1h->is_obj_dead_cond(_containing_obj, _use_prev_marking),
           "Precondition");
    T heap_oop = oopDesc::load_heap_oop(p);
    if (!oopDesc::is_null(heap_oop)) {
      oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
      bool failed = false;
      if (!_g1h->is_in_closed_subset(obj) ||
          _g1h->is_obj_dead_cond(obj, _use_prev_marking)) {
        if (!_failures) {
          gclog_or_tty->print_cr("");
          gclog_or_tty->print_cr("----------");
        }
        if (!_g1h->is_in_closed_subset(obj)) {
          HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
          gclog_or_tty->print_cr("Field "PTR_FORMAT
                                 " of live obj "PTR_FORMAT" in region "
                                 "["PTR_FORMAT", "PTR_FORMAT")",
                                 p, (void*) _containing_obj,
                                 from->bottom(), from->end());
          print_object(gclog_or_tty, _containing_obj);
          gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap",
                                 (void*) obj);
        } else {
          HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
          HeapRegion* to   = _g1h->heap_region_containing((HeapWord*)obj);
          gclog_or_tty->print_cr("Field "PTR_FORMAT
                                 " of live obj "PTR_FORMAT" in region "
                                 "["PTR_FORMAT", "PTR_FORMAT")",
                                 p, (void*) _containing_obj,
                                 from->bottom(), from->end());
          print_object(gclog_or_tty, _containing_obj);
          gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region "
                                 "["PTR_FORMAT", "PTR_FORMAT")",
                                 (void*) obj, to->bottom(), to->end());
          print_object(gclog_or_tty, obj);
        }
        gclog_or_tty->print_cr("----------");
        _failures = true;
        failed = true;
        _n_failures++;
      }

      if (!_g1h->full_collection()) {
        HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
        HeapRegion* to   = _g1h->heap_region_containing(obj);
        if (from != NULL && to != NULL &&
            from != to &&
            !to->isHumongous()) {
          jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
          jbyte cv_field = *_bs->byte_for_const(p);
          const jbyte dirty = CardTableModRefBS::dirty_card_val();

          bool is_bad = !(from->is_young()
                          || to->rem_set()->contains_reference(p)
                          || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
                              (_containing_obj->is_objArray() ?
                                  cv_field == dirty
                               : cv_obj == dirty || cv_field == dirty));
          if (is_bad) {
            if (!_failures) {
              gclog_or_tty->print_cr("");
              gclog_or_tty->print_cr("----------");
            }
            gclog_or_tty->print_cr("Missing rem set entry:");
            gclog_or_tty->print_cr("Field "PTR_FORMAT
                          " of obj "PTR_FORMAT
                          ", in region %d ["PTR_FORMAT
                          ", "PTR_FORMAT"),",
                          p, (void*) _containing_obj,
                          from->hrs_index(),
                          from->bottom(),
                          from->end());
            _containing_obj->print_on(gclog_or_tty);
            gclog_or_tty->print_cr("points to obj "PTR_FORMAT
                          " in region %d ["PTR_FORMAT
                          ", "PTR_FORMAT").",
                          (void*) obj, to->hrs_index(),
                          to->bottom(), to->end());
            obj->print_on(gclog_or_tty);
            gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
                          cv_obj, cv_field);
            gclog_or_tty->print_cr("----------");
            _failures = true;
            if (!failed) _n_failures++;
          }
        }
      }
    }
  }

 template <class T> void do_oop_work(T* p) {
   HeapRegion* to = _g1->heap_region_containing(oopDesc::load_decode_heap_oop(p));
   if (to->in_collection_set()) {
     to->rem_set()->add_reference(p, 0);
   }
 }

 template <class T> void do_oop_work(T* p) {
   oop obj = oopDesc::load_decode_heap_oop(p);
   HeapRegion* to = _g1->heap_region_containing(obj);
   guarantee(to == NULL || !to->in_collection_set(),
             "Missed a rem set member.");
 }