| /* |
| * Copyright (c) 2014, 2016, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" |
| #include "gc_implementation/g1/g1OopClosures.inline.hpp" |
| #include "gc_implementation/g1/g1ParScanThreadState.inline.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "oops/oop.pcgc.inline.hpp" |
| #include "runtime/prefetch.inline.hpp" |
| |
| G1ParScanThreadState::G1ParScanThreadState(G1CollectedHeap* g1h, uint queue_num, ReferenceProcessor* rp) |
| : _g1h(g1h), |
| _refs(g1h->task_queue(queue_num)), |
| _dcq(&g1h->dirty_card_queue_set()), |
| _ct_bs(g1h->g1_barrier_set()), |
| _g1_rem(g1h->g1_rem_set()), |
| _hash_seed(17), _queue_num(queue_num), |
| _term_attempts(0), |
| _tenuring_threshold(g1h->g1_policy()->tenuring_threshold()), |
| _age_table(false), _scanner(g1h, rp), |
| _strong_roots_time(0), _term_time(0) { |
| _scanner.set_par_scan_thread_state(this); |
| // we allocate G1YoungSurvRateNumRegions plus one entries, since |
| // we "sacrifice" entry 0 to keep track of surviving bytes for |
| // non-young regions (where the age is -1) |
| // We also add a few elements at the beginning and at the end in |
| // an attempt to eliminate cache contention |
| uint real_length = 1 + _g1h->g1_policy()->young_cset_region_length(); |
| uint array_length = PADDING_ELEM_NUM + |
| real_length + |
| PADDING_ELEM_NUM; |
| _surviving_young_words_base = NEW_C_HEAP_ARRAY(size_t, array_length, mtGC); |
| if (_surviving_young_words_base == NULL) |
| vm_exit_out_of_memory(array_length * sizeof(size_t), OOM_MALLOC_ERROR, |
| "Not enough space for young surv histo."); |
| _surviving_young_words = _surviving_young_words_base + PADDING_ELEM_NUM; |
| memset(_surviving_young_words, 0, (size_t) real_length * sizeof(size_t)); |
| |
| _g1_par_allocator = G1ParGCAllocator::create_allocator(_g1h); |
| |
| _dest[InCSetState::NotInCSet] = InCSetState::NotInCSet; |
| // The dest for Young is used when the objects are aged enough to |
| // need to be moved to the next space. |
| _dest[InCSetState::Young] = InCSetState::Old; |
| _dest[InCSetState::Old] = InCSetState::Old; |
| |
| _start = os::elapsedTime(); |
| } |
| |
| G1ParScanThreadState::~G1ParScanThreadState() { |
| _g1_par_allocator->retire_alloc_buffers(); |
| delete _g1_par_allocator; |
| FREE_C_HEAP_ARRAY(size_t, _surviving_young_words_base, mtGC); |
| } |
| |
| void |
| G1ParScanThreadState::print_termination_stats_hdr(outputStream* const st) |
| { |
| st->print_raw_cr("GC Termination Stats"); |
| st->print_raw_cr(" elapsed --strong roots-- -------termination-------" |
| " ------waste (KiB)------"); |
| st->print_raw_cr("thr ms ms % ms % attempts" |
| " total alloc undo"); |
| st->print_raw_cr("--- --------- --------- ------ --------- ------ --------" |
| " ------- ------- -------"); |
| } |
| |
| void |
| G1ParScanThreadState::print_termination_stats(int i, |
| outputStream* const st) const |
| { |
| const double elapsed_ms = elapsed_time() * 1000.0; |
| const double s_roots_ms = strong_roots_time() * 1000.0; |
| const double term_ms = term_time() * 1000.0; |
| const size_t alloc_buffer_waste = _g1_par_allocator->alloc_buffer_waste(); |
| const size_t undo_waste = _g1_par_allocator->undo_waste(); |
| st->print_cr("%3d %9.2f %9.2f %6.2f " |
| "%9.2f %6.2f " SIZE_FORMAT_W(8) " " |
| SIZE_FORMAT_W(7) " " SIZE_FORMAT_W(7) " " SIZE_FORMAT_W(7), |
| i, elapsed_ms, s_roots_ms, s_roots_ms * 100 / elapsed_ms, |
| term_ms, term_ms * 100 / elapsed_ms, term_attempts(), |
| (alloc_buffer_waste + undo_waste) * HeapWordSize / K, |
| alloc_buffer_waste * HeapWordSize / K, |
| undo_waste * HeapWordSize / K); |
| } |
| |
| #ifdef ASSERT |
| bool G1ParScanThreadState::verify_ref(narrowOop* ref) const { |
| assert(ref != NULL, "invariant"); |
| assert(UseCompressedOops, "sanity"); |
| assert(!has_partial_array_mask(ref), err_msg("ref=" PTR_FORMAT, p2i(ref))); |
| oop p = oopDesc::load_decode_heap_oop(ref); |
| assert(_g1h->is_in_g1_reserved(p), |
| err_msg("ref=" PTR_FORMAT " p=" PTR_FORMAT, p2i(ref), p2i(p))); |
| return true; |
| } |
| |
| bool G1ParScanThreadState::verify_ref(oop* ref) const { |
| assert(ref != NULL, "invariant"); |
| if (has_partial_array_mask(ref)) { |
| // Must be in the collection set--it's already been copied. |
| oop p = clear_partial_array_mask(ref); |
| assert(_g1h->obj_in_cs(p), |
| err_msg("ref=" PTR_FORMAT " p=" PTR_FORMAT, p2i(ref), p2i(p))); |
| } else { |
| oop p = oopDesc::load_decode_heap_oop(ref); |
| assert(_g1h->is_in_g1_reserved(p), |
| err_msg("ref=" PTR_FORMAT " p=" PTR_FORMAT, p2i(ref), p2i(p))); |
| } |
| return true; |
| } |
| |
| bool G1ParScanThreadState::verify_task(StarTask ref) const { |
| if (ref.is_narrow()) { |
| return verify_ref((narrowOop*) ref); |
| } else { |
| return verify_ref((oop*) ref); |
| } |
| } |
| #endif // ASSERT |
| |
| void G1ParScanThreadState::trim_queue() { |
| assert(_evac_failure_cl != NULL, "not set"); |
| |
| StarTask ref; |
| do { |
| // Drain the overflow stack first, so other threads can steal. |
| while (_refs->pop_overflow(ref)) { |
| if (!_refs->try_push_to_taskqueue(ref)) { |
| dispatch_reference(ref); |
| } |
| } |
| |
| while (_refs->pop_local(ref)) { |
| dispatch_reference(ref); |
| } |
| } while (!_refs->is_empty()); |
| } |
| |
| HeapWord* G1ParScanThreadState::allocate_in_next_plab(InCSetState const state, |
| InCSetState* dest, |
| size_t word_sz, |
| AllocationContext_t const context) { |
| assert(state.is_in_cset_or_humongous(), err_msg("Unexpected state: " CSETSTATE_FORMAT, state.value())); |
| assert(dest->is_in_cset_or_humongous(), err_msg("Unexpected dest: " CSETSTATE_FORMAT, dest->value())); |
| |
| // Right now we only have two types of regions (young / old) so |
| // let's keep the logic here simple. We can generalize it when necessary. |
| if (dest->is_young()) { |
| HeapWord* const obj_ptr = _g1_par_allocator->allocate(InCSetState::Old, |
| word_sz, context); |
| if (obj_ptr == NULL) { |
| return NULL; |
| } |
| // Make sure that we won't attempt to copy any other objects out |
| // of a survivor region (given that apparently we cannot allocate |
| // any new ones) to avoid coming into this slow path. |
| _tenuring_threshold = 0; |
| dest->set_old(); |
| return obj_ptr; |
| } else { |
| assert(dest->is_old(), err_msg("Unexpected dest: " CSETSTATE_FORMAT, dest->value())); |
| // no other space to try. |
| return NULL; |
| } |
| } |
| |
| InCSetState G1ParScanThreadState::next_state(InCSetState const state, markOop const m, uint& age) { |
| if (state.is_young()) { |
| age = !m->has_displaced_mark_helper() ? m->age() |
| : m->displaced_mark_helper()->age(); |
| if (age < _tenuring_threshold) { |
| return state; |
| } |
| } |
| return dest(state); |
| } |
| |
| oop G1ParScanThreadState::copy_to_survivor_space(InCSetState const state, |
| oop const old, |
| markOop const old_mark) { |
| const size_t word_sz = old->size(); |
| HeapRegion* const from_region = _g1h->heap_region_containing_raw(old); |
| // +1 to make the -1 indexes valid... |
| const int young_index = from_region->young_index_in_cset()+1; |
| assert( (from_region->is_young() && young_index > 0) || |
| (!from_region->is_young() && young_index == 0), "invariant" ); |
| const AllocationContext_t context = from_region->allocation_context(); |
| |
| uint age = 0; |
| InCSetState dest_state = next_state(state, old_mark, age); |
| HeapWord* obj_ptr = _g1_par_allocator->plab_allocate(dest_state, word_sz, context); |
| |
| // PLAB allocations should succeed most of the time, so we'll |
| // normally check against NULL once and that's it. |
| if (obj_ptr == NULL) { |
| obj_ptr = _g1_par_allocator->allocate_direct_or_new_plab(dest_state, word_sz, context); |
| if (obj_ptr == NULL) { |
| obj_ptr = allocate_in_next_plab(state, &dest_state, word_sz, context); |
| if (obj_ptr == NULL) { |
| // This will either forward-to-self, or detect that someone else has |
| // installed a forwarding pointer. |
| return _g1h->handle_evacuation_failure_par(this, old); |
| } |
| } |
| } |
| |
| assert(obj_ptr != NULL, "when we get here, allocation should have succeeded"); |
| #ifndef PRODUCT |
| // Should this evacuation fail? |
| if (_g1h->evacuation_should_fail()) { |
| // Doing this after all the allocation attempts also tests the |
| // undo_allocation() method too. |
| _g1_par_allocator->undo_allocation(dest_state, obj_ptr, word_sz, context); |
| return _g1h->handle_evacuation_failure_par(this, old); |
| } |
| #endif // !PRODUCT |
| |
| // We're going to allocate linearly, so might as well prefetch ahead. |
| Prefetch::write(obj_ptr, PrefetchCopyIntervalInBytes); |
| |
| const oop obj = oop(obj_ptr); |
| const oop forward_ptr = old->forward_to_atomic(obj); |
| if (forward_ptr == NULL) { |
| Copy::aligned_disjoint_words((HeapWord*) old, obj_ptr, word_sz); |
| |
| if (dest_state.is_young()) { |
| if (age < markOopDesc::max_age) { |
| age++; |
| } |
| if (old_mark->has_displaced_mark_helper()) { |
| // In this case, we have to install the mark word first, |
| // otherwise obj looks to be forwarded (the old mark word, |
| // which contains the forward pointer, was copied) |
| obj->set_mark(old_mark); |
| markOop new_mark = old_mark->displaced_mark_helper()->set_age(age); |
| old_mark->set_displaced_mark_helper(new_mark); |
| } else { |
| obj->set_mark(old_mark->set_age(age)); |
| } |
| age_table()->add(age, word_sz); |
| } else { |
| obj->set_mark(old_mark); |
| } |
| |
| if (G1StringDedup::is_enabled()) { |
| const bool is_from_young = state.is_young(); |
| const bool is_to_young = dest_state.is_young(); |
| assert(is_from_young == _g1h->heap_region_containing_raw(old)->is_young(), |
| "sanity"); |
| assert(is_to_young == _g1h->heap_region_containing_raw(obj)->is_young(), |
| "sanity"); |
| G1StringDedup::enqueue_from_evacuation(is_from_young, |
| is_to_young, |
| queue_num(), |
| obj); |
| } |
| |
| size_t* const surv_young_words = surviving_young_words(); |
| surv_young_words[young_index] += word_sz; |
| |
| if (obj->is_objArray() && arrayOop(obj)->length() >= ParGCArrayScanChunk) { |
| // We keep track of the next start index in the length field of |
| // the to-space object. The actual length can be found in the |
| // length field of the from-space object. |
| arrayOop(obj)->set_length(0); |
| oop* old_p = set_partial_array_mask(old); |
| push_on_queue(old_p); |
| } else { |
| HeapRegion* const to_region = _g1h->heap_region_containing_raw(obj_ptr); |
| _scanner.set_region(to_region); |
| obj->oop_iterate_backwards(&_scanner); |
| } |
| return obj; |
| } else { |
| _g1_par_allocator->undo_allocation(dest_state, obj_ptr, word_sz, context); |
| return forward_ptr; |
| } |
| } |
