Example #1
0
  /**
   * Perform garbage collection on the young objects.
   */
  void BakerGC::collect(GCData& data, YoungCollectStats* stats) {

#ifdef HAVE_VALGRIND_H
    VALGRIND_MAKE_MEM_DEFINED(next->start().as_int(), next->size());
    VALGRIND_MAKE_MEM_DEFINED(current->start().as_int(), current->size());
#endif

    Object* tmp;
    ObjectArray *current_rs = object_memory_->swap_remember_set();

    total_objects = 0;

    copy_spills_ = 0;
    reset_promoted();

    // Start by copying objects in the remember set
    for(ObjectArray::iterator oi = current_rs->begin();
        oi != current_rs->end();
        ++oi) {
      tmp = *oi;
      // unremember_object throws a NULL in to remove an object
      // so we don't have to compact the set in unremember
      if(tmp) {
        // assert(tmp->mature_object_p());
        // assert(!tmp->forwarded_p());

        // Remove the Remember bit, since we're clearing the set.
        tmp->clear_remember();
        scan_object(tmp);
      }
    }

    delete current_rs;

    for(std::list<gc::WriteBarrier*>::iterator wbi = object_memory_->aux_barriers().begin();
        wbi != object_memory_->aux_barriers().end();
        ++wbi) {
      gc::WriteBarrier* wb = *wbi;
      ObjectArray* rs = wb->swap_remember_set();
      for(ObjectArray::iterator oi = rs->begin();
          oi != rs->end();
          ++oi) {
        tmp = *oi;

        if(tmp) {
          tmp->clear_remember();
          scan_object(tmp);
        }
      }

      delete rs;
    }

    for(Roots::Iterator i(data.roots()); i.more(); i.advance()) {
      i->set(saw_object(i->get()));
    }

    if(data.threads()) {
      for(std::list<ManagedThread*>::iterator i = data.threads()->begin();
          i != data.threads()->end();
          ++i) {
        scan(*i, true);
      }
    }

    for(Allocator<capi::Handle>::Iterator i(data.handles()->allocator()); i.more(); i.advance()) {
      if(!i->in_use_p()) continue;

      if(!i->weak_p() && i->object()->young_object_p()) {
        i->set_object(saw_object(i->object()));

      // Users manipulate values accessible from the data* within an
      // RData without running a write barrier. Thusly if we see a mature
      // rdata, we must always scan it because it could contain
      // young pointers.
      } else if(!i->object()->young_object_p() && i->is_rdata()) {
        scan_object(i->object());
      }

      assert(i->object()->type_id() > InvalidType && i->object()->type_id() < LastObjectType);
    }

    std::list<capi::GlobalHandle*>* gh = data.global_handle_locations();

    if(gh) {
      for(std::list<capi::GlobalHandle*>::iterator i = gh->begin();
          i != gh->end();
          ++i) {
        capi::GlobalHandle* global_handle = *i;
        capi::Handle** loc = global_handle->handle();
        if(capi::Handle* hdl = *loc) {
          if(!REFERENCE_P(hdl)) continue;
          if(hdl->valid_p()) {
            Object* obj = hdl->object();
            if(obj && obj->reference_p() && obj->young_object_p()) {
              hdl->set_object(saw_object(obj));
            }
          } else {
            std::cerr << "Detected bad handle checking global capi handles\n";
          }
        }
      }
    }

#ifdef ENABLE_LLVM
    if(LLVMState* ls = data.llvm_state()) ls->gc_scan(this);
#endif

    // Handle all promotions to non-young space that occurred.
    handle_promotions();

    assert(fully_scanned_p());
    // We're now done seeing the entire object graph of normal, live references.
    // Now we get to handle the unusual references, like finalizers and such.

    // Objects with finalizers must be kept alive until the finalizers have
    // run.
    walk_finalizers();

    // Process possible promotions from processing objects with finalizers.
    handle_promotions();

    if(!promoted_stack_.empty()) rubinius::bug("promote stack has elements!");
    if(!fully_scanned_p()) rubinius::bug("more young refs");

    // Check any weakrefs and replace dead objects with nil
    clean_weakrefs(true);

    // Swap the 2 halves
    Heap *x = next;
    next = current;
    current = x;

    if(stats) {
      stats->lifetime = lifetime_;
      stats->percentage_used = current->percentage_used();
      stats->promoted_objects = promoted_objects_;
      stats->excess_objects = copy_spills_;
    }

    // Tune the age at which promotion occurs
    if(autotune_) {
      double used = current->percentage_used();
      if(used > cOverFullThreshold) {
        if(tune_threshold_ >= cOverFullTimes) {
          if(lifetime_ > cMinimumLifetime) lifetime_--;
        } else {
          tune_threshold_++;
        }
      } else if(used < cUnderFullThreshold) {
        if(tune_threshold_ <= cUnderFullTimes) {
          if(lifetime_ < cMaximumLifetime) lifetime_++;
        } else {
          tune_threshold_--;
        }
      } else if(tune_threshold_ > 0) {
        tune_threshold_--;
      } else if(tune_threshold_ < 0) {
        tune_threshold_++;
      } else if(tune_threshold_ == 0) {
        if(lifetime_ < original_lifetime_) {
          lifetime_++;
        } else if(lifetime_ > original_lifetime_) {
          lifetime_--;
        }
      }
    }

  }
Example #2
0
  /**
   * Performs a garbage collection of the immix space.
   */
  void ImmixGC::collect(GCData& data) {
    Object* tmp;

    gc_.clear_lines();

    int via_handles_ = 0;
    int via_roots = 0;

    for(Roots::Iterator i(data.roots()); i.more(); i.advance()) {
      tmp = i->get();
      if(tmp->reference_p()) saw_object(tmp);
      via_roots++;
    }

    if(data.threads()) {
      for(std::list<ManagedThread*>::iterator i = data.threads()->begin();
          i != data.threads()->end();
          ++i) {
        scan(*i, false);
      }
    }

    for(Allocator<capi::Handle>::Iterator i(data.handles()->allocator()); i.more(); i.advance()) {
      if(i->in_use_p() && !i->weak_p()) {
        saw_object(i->object());
        via_handles_++;
      }
    }

    std::list<capi::GlobalHandle*>* gh = data.global_handle_locations();

    if(gh) {
      for(std::list<capi::GlobalHandle*>::iterator i = gh->begin();
          i != gh->end();
          ++i) {
        capi::Handle** loc = (*i)->handle();
        if(capi::Handle* hdl = *loc) {
          if(!REFERENCE_P(hdl)) continue;
          if(hdl->valid_p()) {
            Object* obj = hdl->object();
            if(obj && obj->reference_p()) {
              saw_object(obj);
              via_handles_++;
            }
          } else {
            std::cerr << "Detected bad handle checking global capi handles\n";
          }
        }
      }
    }

#ifdef ENABLE_LLVM
    if(LLVMState* ls = data.llvm_state()) ls->gc_scan(this);
#endif

    gc_.process_mark_stack(allocator_);

    // We've now finished marking the entire object graph.

    // Marking objects to be Finalized can cause more things to continue to
    // live, so we must check the mark_stack again.
    do {
      walk_finalizers();
    } while(gc_.process_mark_stack(allocator_));

    clean_weakrefs();

    // Remove unreachable locked objects still in the list
    if(data.threads()) {
      for(std::list<ManagedThread*>::iterator i = data.threads()->begin();
          i != data.threads()->end();
          ++i) {
        clean_locked_objects(*i, false);
      }
    }

    // Sweep up the garbage
    gc_.sweep_blocks();

    // This resets the allocator state to sync it up with the BlockAllocator
    // properly.
    allocator_.get_new_block();

    // Clear unreachable objects from the various remember sets
    int cleared = 0;
    unsigned int mark = object_memory_->mark();
    cleared = object_memory_->unremember_objects(mark);
    for(std::list<gc::WriteBarrier*>::iterator wbi = object_memory_->aux_barriers().begin();
        wbi != object_memory_->aux_barriers().end();
        ++wbi) {
      gc::WriteBarrier* wb = *wbi;
      cleared += wb->unremember_objects(mark);
    }

    // Now, calculate how much space we're still using.
    immix::Chunks& chunks = gc_.block_allocator().chunks();
    immix::AllBlockIterator iter(chunks);

    int live_bytes = 0;
    int total_bytes = 0;

    while(immix::Block* block = iter.next()) {
      total_bytes += immix::cBlockSize;
      live_bytes += block->bytes_from_lines();
    }

    double percentage_live = (double)live_bytes / (double)total_bytes;

    if(object_memory_->state()->shared.config.gc_immix_debug) {
      std::cerr << "[GC IMMIX: " << clear_marked_objects() << " marked"
                << ", "
                << via_roots << " roots "
                << via_handles_ << " handles "
                << (int)(percentage_live * 100) << "% live"
                << ", " << live_bytes << "/" << total_bytes
                << "]\n";
    }

    if(percentage_live >= 0.90) {
      if(object_memory_->state()->shared.config.gc_immix_debug) {
        std::cerr << "[GC IMMIX: expanding. "
                   << (int)(percentage_live * 100)
                   << "%]\n";
      }
      gc_.block_allocator().add_chunk();
    }

#ifdef IMMIX_DEBUG
    std::cout << "Immix: RS size cleared: " << cleared << "\n";

    immix::Chunks& chunks = gc_.block_allocator().chunks();
    std::cout << "chunks=" << chunks.size() << "\n";

    immix::AllBlockIterator iter(chunks);

    int blocks_seen = 0;
    int total_objects = 0;
    int total_object_bytes = 0;

    while(immix::Block* block = iter.next()) {
      blocks_seen++;
      std::cout << "block " << block << ", holes=" << block->holes() << " "
                << "objects=" << block->objects() << " "
                << "object_bytes=" << block->object_bytes() << " "
                << "frag=" << block->fragmentation_ratio()
                << "\n";

      total_objects += block->objects();
      total_object_bytes += block->object_bytes();
    }

    std::cout << blocks_seen << " blocks\n";
    std::cout << gc_.bytes_allocated() << " bytes allocated\n";
    std::cout << total_object_bytes << " object bytes / " << total_objects << " objects\n";

    int* holes = new int[10];
    for(int i = 0; i < 10; i++) {
      holes[i] = 0;
    }

    immix::AllBlockIterator iter2(chunks);

    while(immix::Block* block = iter2.next()) {
      int h = block->holes();
      if(h > 9) h = 9;

      holes[h]++;
    }

    std::cout << "== hole stats ==\n";
    for(int i = 0; i < 10; i++) {
      if(holes[i] > 0) {
        std::cout << i << ": " << holes[i] << "\n";
      }
    }

    delete[] holes;
    holes = NULL;
#endif
  }