C++ GenCollectedHeap::reset_promotion_should_fail方法代码示例

//.........这里部分代码省略.........
  set_promo_failure_scan_stack_closure(&fsc_with_no_gc_barrier);
  FastEvacuateFollowersClosure evacuate_followers(gch,
                                                  &fsc_with_no_gc_barrier,
                                                  &fsc_with_gc_barrier);

  assert(gch->no_allocs_since_save_marks(),
         "save marks have not been newly set.");

  {
    // DefNew needs to run with n_threads == 0, to make sure the serial
    // version of the card table scanning code is used.
    // See: CardTableModRefBSForCTRS::non_clean_card_iterate_possibly_parallel.
    StrongRootsScope srs(0);

    gch->gen_process_roots(&srs,
                           GenCollectedHeap::YoungGen,
                           true,  // Process younger gens, if any,
                                  // as strong roots.
                           GenCollectedHeap::SO_ScavengeCodeCache,
                           GenCollectedHeap::StrongAndWeakRoots,
                           &fsc_with_no_gc_barrier,
                           &fsc_with_gc_barrier,
                           &cld_scan_closure);
  }

  // "evacuate followers".
  evacuate_followers.do_void();

  FastKeepAliveClosure keep_alive(this, &scan_weak_ref);
  ReferenceProcessor* rp = ref_processor();
  rp->setup_policy(clear_all_soft_refs);
  const ReferenceProcessorStats& stats =
  rp->process_discovered_references(&is_alive, &keep_alive, &evacuate_followers,
                                    NULL, _gc_timer);
  gc_tracer.report_gc_reference_stats(stats);
  gc_tracer.report_tenuring_threshold(tenuring_threshold());

  if (!_promotion_failed) {
    // Swap the survivor spaces.
    eden()->clear(SpaceDecorator::Mangle);
    from()->clear(SpaceDecorator::Mangle);
    if (ZapUnusedHeapArea) {
      // This is now done here because of the piece-meal mangling which
      // can check for valid mangling at intermediate points in the
      // collection(s).  When a young collection fails to collect
      // sufficient space resizing of the young generation can occur
      // an redistribute the spaces in the young generation.  Mangle
      // here so that unzapped regions don't get distributed to
      // other spaces.
      to()->mangle_unused_area();
    }
    swap_spaces();

    assert(to()->is_empty(), "to space should be empty now");

    adjust_desired_tenuring_threshold();

    // A successful scavenge should restart the GC time limit count which is
    // for full GC's.
    AdaptiveSizePolicy* size_policy = gch->gen_policy()->size_policy();
    size_policy->reset_gc_overhead_limit_count();
    assert(!gch->incremental_collection_failed(), "Should be clear");
  } else {
    assert(_promo_failure_scan_stack.is_empty(), "post condition");
    _promo_failure_scan_stack.clear(true); // Clear cached segments.

    remove_forwarding_pointers();
    log_debug(gc)("Promotion failed");
    // Add to-space to the list of space to compact
    // when a promotion failure has occurred.  In that
    // case there can be live objects in to-space
    // as a result of a partial evacuation of eden
    // and from-space.
    swap_spaces();   // For uniformity wrt ParNewGeneration.
    from()->set_next_compaction_space(to());
    gch->set_incremental_collection_failed();

    // Inform the next generation that a promotion failure occurred.
    _old_gen->promotion_failure_occurred();
    gc_tracer.report_promotion_failed(_promotion_failed_info);

    // Reset the PromotionFailureALot counters.
    NOT_PRODUCT(gch->reset_promotion_should_fail();)
  }
  // set new iteration safe limit for the survivor spaces
  from()->set_concurrent_iteration_safe_limit(from()->top());
  to()->set_concurrent_iteration_safe_limit(to()->top());

  // We need to use a monotonically non-decreasing time in ms
  // or we will see time-warp warnings and os::javaTimeMillis()
  // does not guarantee monotonicity.
  jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
  update_time_of_last_gc(now);

  gch->trace_heap_after_gc(&gc_tracer);

  _gc_timer->register_gc_end();

  gc_tracer.report_gc_end(_gc_timer->gc_end(), _gc_timer->time_partitions());
}