66 #include "runtime/prefetch.inline.hpp"

    70 #include "utilities/ticks.hpp"

  4562 G1ParScanThreadState::G1ParScanThreadState(G1CollectedHeap* g1h, uint queue_num, ReferenceProcessor* rp)

  4563   : _g1h(g1h),

  4564     _refs(g1h->task_queue(queue_num)),

  4565     _dcq(&g1h->dirty_card_queue_set()),

  4566     _ct_bs(g1h->g1_barrier_set()),

  4567     _g1_rem(g1h->g1_rem_set()),

  4568     _hash_seed(17), _queue_num(queue_num),

  4569     _term_attempts(0),

  4570     _surviving_alloc_buffer(g1h->desired_plab_sz(GCAllocForSurvived)),

  4571     _tenured_alloc_buffer(g1h->desired_plab_sz(GCAllocForTenured)),

  4572     _age_table(false), _scanner(g1h, this, rp),

  4573     _strong_roots_time(0), _term_time(0),

  4574     _alloc_buffer_waste(0), _undo_waste(0) {

  4575   // we allocate G1YoungSurvRateNumRegions plus one entries, since

  4576   // we "sacrifice" entry 0 to keep track of surviving bytes for

  4577   // non-young regions (where the age is -1)

  4578   // We also add a few elements at the beginning and at the end in

  4579   // an attempt to eliminate cache contention

  4580   uint real_length = 1 + _g1h->g1_policy()->young_cset_region_length();

  4581   uint array_length = PADDING_ELEM_NUM +

  4582                       real_length +

  4583                       PADDING_ELEM_NUM;

  4584   _surviving_young_words_base = NEW_C_HEAP_ARRAY(size_t, array_length, mtGC);

  4585   if (_surviving_young_words_base == NULL)

  4586     vm_exit_out_of_memory(array_length * sizeof(size_t), OOM_MALLOC_ERROR,

  4587                           "Not enough space for young surv histo.");

  4588   _surviving_young_words = _surviving_young_words_base + PADDING_ELEM_NUM;

  4589   memset(_surviving_young_words, 0, (size_t) real_length * sizeof(size_t));

  4590 

  4591   _alloc_buffers[GCAllocForSurvived] = &_surviving_alloc_buffer;

  4592   _alloc_buffers[GCAllocForTenured]  = &_tenured_alloc_buffer;

  4593 

  4594   _start = os::elapsedTime();

  4595 }

  4596 

  4597 void

  4598 G1ParScanThreadState::print_termination_stats_hdr(outputStream* const st)

  4599 {

  4600   st->print_raw_cr("GC Termination Stats");

  4601   st->print_raw_cr("     elapsed  --strong roots-- -------termination-------"

  4602                    " ------waste (KiB)------");

  4603   st->print_raw_cr("thr     ms        ms      %        ms      %    attempts"

  4604                    "  total   alloc    undo");

  4605   st->print_raw_cr("--- --------- --------- ------ --------- ------ --------"

  4606                    " ------- ------- -------");

  4607 }

  4608 

  4609 void

  4610 G1ParScanThreadState::print_termination_stats(int i,

  4611                                               outputStream* const st) const

  4612 {

  4613   const double elapsed_ms = elapsed_time() * 1000.0;

  4614   const double s_roots_ms = strong_roots_time() * 1000.0;

  4615   const double term_ms    = term_time() * 1000.0;

  4616   st->print_cr("%3d %9.2f %9.2f %6.2f "

  4617                "%9.2f %6.2f " SIZE_FORMAT_W(8) " "

  4618                SIZE_FORMAT_W(7) " " SIZE_FORMAT_W(7) " " SIZE_FORMAT_W(7),

  4619                i, elapsed_ms, s_roots_ms, s_roots_ms * 100 / elapsed_ms,

  4620                term_ms, term_ms * 100 / elapsed_ms, term_attempts(),

  4621                (alloc_buffer_waste() + undo_waste()) * HeapWordSize / K,

  4622                alloc_buffer_waste() * HeapWordSize / K,

  4623                undo_waste() * HeapWordSize / K);

  4624 }

  4625 

  4626 #ifdef ASSERT

  4627 bool G1ParScanThreadState::verify_ref(narrowOop* ref) const {

  4628   assert(ref != NULL, "invariant");

  4629   assert(UseCompressedOops, "sanity");

  4630   assert(!has_partial_array_mask(ref), err_msg("ref=" PTR_FORMAT, ref));

  4631   oop p = oopDesc::load_decode_heap_oop(ref);

  4632   assert(_g1h->is_in_g1_reserved(p),

  4633          err_msg("ref=" PTR_FORMAT " p=" PTR_FORMAT, ref, (void *)p));

  4634   return true;

  4635 }

  4636 

  4637 bool G1ParScanThreadState::verify_ref(oop* ref) const {

  4638   assert(ref != NULL, "invariant");

  4639   if (has_partial_array_mask(ref)) {

  4640     // Must be in the collection set--it's already been copied.

  4641     oop p = clear_partial_array_mask(ref);

  4642     assert(_g1h->obj_in_cs(p),

  4643            err_msg("ref=" PTR_FORMAT " p=" PTR_FORMAT, ref, (void *)p));

  4644   } else {

  4645     oop p = oopDesc::load_decode_heap_oop(ref);

  4646     assert(_g1h->is_in_g1_reserved(p),

  4647            err_msg("ref=" PTR_FORMAT " p=" PTR_FORMAT, ref, (void *)p));

  4648   }

  4649   return true;

  4650 }

  4651 

  4652 bool G1ParScanThreadState::verify_task(StarTask ref) const {

  4653   if (ref.is_narrow()) {

  4654     return verify_ref((narrowOop*) ref);

  4655   } else {

  4656     return verify_ref((oop*) ref);

  4657   }

  4658 }

  4659 #endif // ASSERT

  4660 

  4661 void G1ParScanThreadState::trim_queue() {

  4662   assert(_evac_failure_cl != NULL, "not set");

  4663 

  4664   StarTask ref;

  4665   do {

  4666     // Drain the overflow stack first, so other threads can steal.

  4667     while (refs()->pop_overflow(ref)) {

  4668       deal_with_reference(ref);

  4669     }

  4670 

  4671     while (refs()->pop_local(ref)) {

  4672       deal_with_reference(ref);

  4673     }

  4674   } while (!refs()->is_empty());

  4675 }

  4676 

  4677 G1ParClosureSuper::G1ParClosureSuper(G1CollectedHeap* g1,

  4678                                      G1ParScanThreadState* par_scan_state) :

  4679   _g1(g1), _par_scan_state(par_scan_state),

  4680   _worker_id(par_scan_state->queue_num()) { }

  4681 

  4702 }

  4703 

  4704 oop G1ParScanThreadState::copy_to_survivor_space(oop const old) {

  4705   size_t word_sz = old->size();

  4706   HeapRegion* from_region = _g1h->heap_region_containing_raw(old);

  4707   // +1 to make the -1 indexes valid...

  4708   int       young_index = from_region->young_index_in_cset()+1;

  4709   assert( (from_region->is_young() && young_index >  0) ||

  4710          (!from_region->is_young() && young_index == 0), "invariant" );

  4711   G1CollectorPolicy* g1p = _g1h->g1_policy();

  4712   markOop m = old->mark();

  4713   int age = m->has_displaced_mark_helper() ? m->displaced_mark_helper()->age()

  4714                                            : m->age();

  4715   GCAllocPurpose alloc_purpose = g1p->evacuation_destination(from_region, age,

  4716                                                              word_sz);

  4717   HeapWord* obj_ptr = allocate(alloc_purpose, word_sz);

  4718 #ifndef PRODUCT

  4719   // Should this evacuation fail?

  4720   if (_g1h->evacuation_should_fail()) {

  4721     if (obj_ptr != NULL) {

  4722       undo_allocation(alloc_purpose, obj_ptr, word_sz);

  4723       obj_ptr = NULL;

  4724     }

  4725   }

  4726 #endif // !PRODUCT

  4727 

  4728   if (obj_ptr == NULL) {

  4729     // This will either forward-to-self, or detect that someone else has

  4730     // installed a forwarding pointer.

  4731     return _g1h->handle_evacuation_failure_par(this, old);

  4732   }

  4733 

  4734   oop obj = oop(obj_ptr);

  4735 

  4736   // We're going to allocate linearly, so might as well prefetch ahead.

  4737   Prefetch::write(obj_ptr, PrefetchCopyIntervalInBytes);

  4738 

  4739   oop forward_ptr = old->forward_to_atomic(obj);

  4740   if (forward_ptr == NULL) {

  4741     Copy::aligned_disjoint_words((HeapWord*) old, obj_ptr, word_sz);

  4742 

  4743     // alloc_purpose is just a hint to allocate() above, recheck the type of region

  4744     // we actually allocated from and update alloc_purpose accordingly

  4745     HeapRegion* to_region = _g1h->heap_region_containing_raw(obj_ptr);

  4746     alloc_purpose = to_region->is_young() ? GCAllocForSurvived : GCAllocForTenured;

  4747 

  4748     if (g1p->track_object_age(alloc_purpose)) {

  4749       // We could simply do obj->incr_age(). However, this causes a

  4750       // performance issue. obj->incr_age() will first check whether

  4751       // the object has a displaced mark by checking its mark word;

  4752       // getting the mark word from the new location of the object

  4753       // stalls. So, given that we already have the mark word and we

  4754       // are about to install it anyway, it's better to increase the

  4755       // age on the mark word, when the object does not have a

  4756       // displaced mark word. We're not expecting many objects to have

  4757       // a displaced marked word, so that case is not optimized

  4758       // further (it could be...) and we simply call obj->incr_age().

  4759 

  4760       if (m->has_displaced_mark_helper()) {

  4761         // in this case, we have to install the mark word first,

  4762         // otherwise obj looks to be forwarded (the old mark word,

  4763         // which contains the forward pointer, was copied)

  4764         obj->set_mark(m);

  4765         obj->incr_age();

  4766       } else {

  4767         m = m->incr_age();

  4768         obj->set_mark(m);

  4769       }

  4770       age_table()->add(obj, word_sz);

  4771     } else {

  4772       obj->set_mark(m);

  4773     }

  4774 

  4775     if (G1StringDedup::is_enabled()) {

  4776       G1StringDedup::enqueue_from_evacuation(from_region->is_young(),

  4777                                              to_region->is_young(),

  4778                                              queue_num(),

  4779                                              obj);

  4780     }

  4781 

  4782     size_t* surv_young_words = surviving_young_words();

  4783     surv_young_words[young_index] += word_sz;

  4784 

  4785     if (obj->is_objArray() && arrayOop(obj)->length() >= ParGCArrayScanChunk) {

  4786       // We keep track of the next start index in the length field of

  4787       // the to-space object. The actual length can be found in the

  4788       // length field of the from-space object.

  4789       arrayOop(obj)->set_length(0);

  4790       oop* old_p = set_partial_array_mask(old);

  4791       push_on_queue(old_p);

  4792     } else {

  4793       // No point in using the slower heap_region_containing() method,

  4794       // given that we know obj is in the heap.

  4795       _scanner.set_region(_g1h->heap_region_containing_raw(obj));

  4796       obj->oop_iterate_backwards(&_scanner);

  4797     }

  4798   } else {

  4799     undo_allocation(alloc_purpose, obj_ptr, word_sz);

  4800     obj = forward_ptr;

  4801   }

  4802   return obj;