| /* |
| * Copyright (c) 2014, 2018, 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/g1/g1Allocator.inline.hpp" |
| #include "gc/g1/g1CollectedHeap.inline.hpp" |
| #include "gc/g1/g1CollectionSet.hpp" |
| #include "gc/g1/g1OopClosures.inline.hpp" |
| #include "gc/g1/g1ParScanThreadState.inline.hpp" |
| #include "gc/g1/g1RootClosures.hpp" |
| #include "gc/g1/g1StringDedup.hpp" |
| #include "gc/shared/gcTrace.hpp" |
| #include "gc/shared/taskqueue.inline.hpp" |
| #include "memory/allocation.inline.hpp" |
| #include "oops/access.inline.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "runtime/prefetch.inline.hpp" |
| |
| G1ParScanThreadState::G1ParScanThreadState(G1CollectedHeap* g1h, uint worker_id, size_t young_cset_length) |
| : _g1h(g1h), |
| _refs(g1h->task_queue(worker_id)), |
| _dcq(&g1h->dirty_card_queue_set()), |
| _ct(g1h->card_table()), |
| _closures(NULL), |
| _plab_allocator(NULL), |
| _age_table(false), |
| _tenuring_threshold(g1h->g1_policy()->tenuring_threshold()), |
| _scanner(g1h, this), |
| _hash_seed(17), |
| _worker_id(worker_id), |
| _stack_trim_upper_threshold(GCDrainStackTargetSize * 2 + 1), |
| _stack_trim_lower_threshold(GCDrainStackTargetSize), |
| _trim_ticks(), |
| _old_gen_is_full(false) |
| { |
| // 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 |
| size_t real_length = 1 + young_cset_length; |
| size_t 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, real_length * sizeof(size_t)); |
| |
| _plab_allocator = new G1PLABAllocator(_g1h->allocator()); |
| |
| _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; |
| |
| _closures = G1EvacuationRootClosures::create_root_closures(this, _g1h); |
| } |
| |
| // Pass locally gathered statistics to global state. |
| void G1ParScanThreadState::flush(size_t* surviving_young_words) { |
| _dcq.flush(); |
| // Update allocation statistics. |
| _plab_allocator->flush_and_retire_stats(); |
| _g1h->g1_policy()->record_age_table(&_age_table); |
| |
| uint length = _g1h->collection_set()->young_region_length(); |
| for (uint region_index = 0; region_index < length; region_index++) { |
| surviving_young_words[region_index] += _surviving_young_words[region_index]; |
| } |
| } |
| |
| G1ParScanThreadState::~G1ParScanThreadState() { |
| delete _plab_allocator; |
| delete _closures; |
| FREE_C_HEAP_ARRAY(size_t, _surviving_young_words_base); |
| } |
| |
| void G1ParScanThreadState::waste(size_t& wasted, size_t& undo_wasted) { |
| _plab_allocator->waste(wasted, undo_wasted); |
| } |
| |
| #ifdef ASSERT |
| bool G1ParScanThreadState::verify_ref(narrowOop* ref) const { |
| assert(ref != NULL, "invariant"); |
| assert(UseCompressedOops, "sanity"); |
| assert(!has_partial_array_mask(ref), "ref=" PTR_FORMAT, p2i(ref)); |
| oop p = RawAccess<>::oop_load(ref); |
| assert(_g1h->is_in_g1_reserved(p), |
| "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->is_in_cset(p), |
| "ref=" PTR_FORMAT " p=" PTR_FORMAT, p2i(ref), p2i(p)); |
| } else { |
| oop p = RawAccess<>::oop_load(ref); |
| assert(_g1h->is_in_g1_reserved(p), |
| "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() { |
| StarTask ref; |
| do { |
| // Fully drain the queue. |
| trim_queue_to_threshold(0); |
| } while (!_refs->is_empty()); |
| } |
| |
| HeapWord* G1ParScanThreadState::allocate_in_next_plab(InCSetState const state, |
| InCSetState* dest, |
| size_t word_sz, |
| bool previous_plab_refill_failed) { |
| assert(state.is_in_cset_or_humongous(), "Unexpected state: " CSETSTATE_FORMAT, state.value()); |
| assert(dest->is_in_cset_or_humongous(), "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()) { |
| bool plab_refill_in_old_failed = false; |
| HeapWord* const obj_ptr = _plab_allocator->allocate(InCSetState::Old, |
| word_sz, |
| &plab_refill_in_old_failed); |
| // 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 again and again. |
| // Only consider failed PLAB refill here: failed inline allocations are |
| // typically large, so not indicative of remaining space. |
| if (previous_plab_refill_failed) { |
| _tenuring_threshold = 0; |
| } |
| |
| if (obj_ptr != NULL) { |
| dest->set_old(); |
| } else { |
| // We just failed to allocate in old gen. The same idea as explained above |
| // for making survivor gen unavailable for allocation applies for old gen. |
| _old_gen_is_full = plab_refill_in_old_failed; |
| } |
| return obj_ptr; |
| } else { |
| _old_gen_is_full = previous_plab_refill_failed; |
| assert(dest->is_old(), "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); |
| } |
| |
| void G1ParScanThreadState::report_promotion_event(InCSetState const dest_state, |
| oop const old, size_t word_sz, uint age, |
| HeapWord * const obj_ptr) const { |
| PLAB* alloc_buf = _plab_allocator->alloc_buffer(dest_state); |
| if (alloc_buf->contains(obj_ptr)) { |
| _g1h->_gc_tracer_stw->report_promotion_in_new_plab_event(old->klass(), word_sz, age, |
| dest_state.value() == InCSetState::Old, |
| alloc_buf->word_sz()); |
| } else { |
| _g1h->_gc_tracer_stw->report_promotion_outside_plab_event(old->klass(), word_sz, age, |
| dest_state.value() == InCSetState::Old); |
| } |
| } |
| |
| 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(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" ); |
| |
| uint age = 0; |
| InCSetState dest_state = next_state(state, old_mark, age); |
| // The second clause is to prevent premature evacuation failure in case there |
| // is still space in survivor, but old gen is full. |
| if (_old_gen_is_full && dest_state.is_old()) { |
| return handle_evacuation_failure_par(old, old_mark); |
| } |
| HeapWord* obj_ptr = _plab_allocator->plab_allocate(dest_state, word_sz); |
| |
| // PLAB allocations should succeed most of the time, so we'll |
| // normally check against NULL once and that's it. |
| if (obj_ptr == NULL) { |
| bool plab_refill_failed = false; |
| obj_ptr = _plab_allocator->allocate_direct_or_new_plab(dest_state, word_sz, &plab_refill_failed); |
| if (obj_ptr == NULL) { |
| obj_ptr = allocate_in_next_plab(state, &dest_state, word_sz, plab_refill_failed); |
| if (obj_ptr == NULL) { |
| // This will either forward-to-self, or detect that someone else has |
| // installed a forwarding pointer. |
| return handle_evacuation_failure_par(old, old_mark); |
| } |
| } |
| if (_g1h->_gc_tracer_stw->should_report_promotion_events()) { |
| // The events are checked individually as part of the actual commit |
| report_promotion_event(dest_state, old, word_sz, age, obj_ptr); |
| } |
| } |
| |
| assert(obj_ptr != NULL, "when we get here, allocation should have succeeded"); |
| assert(_g1h->is_in_reserved(obj_ptr), "Allocated memory should be in the heap"); |
| |
| #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. |
| _plab_allocator->undo_allocation(dest_state, obj_ptr, word_sz); |
| return handle_evacuation_failure_par(old, old_mark); |
| } |
| #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, memory_order_relaxed); |
| if (forward_ptr == NULL) { |
| Copy::aligned_disjoint_words((HeapWord*) old, obj_ptr, word_sz); |
| |
| if (dest_state.is_young()) { |
| if (age < markOop::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_raw(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_raw(old_mark.set_age(age)); |
| } |
| _age_table.add(age, word_sz); |
| } else { |
| obj->set_mark_raw(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(old)->is_young(), |
| "sanity"); |
| assert(is_to_young == _g1h->heap_region_containing(obj)->is_young(), |
| "sanity"); |
| G1StringDedup::enqueue_from_evacuation(is_from_young, |
| is_to_young, |
| _worker_id, |
| obj); |
| } |
| |
| _surviving_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); |
| do_oop_partial_array(old_p); |
| } else { |
| HeapRegion* const to_region = _g1h->heap_region_containing(obj_ptr); |
| _scanner.set_region(to_region); |
| obj->oop_iterate_backwards(&_scanner); |
| } |
| return obj; |
| } else { |
| _plab_allocator->undo_allocation(dest_state, obj_ptr, word_sz); |
| return forward_ptr; |
| } |
| } |
| |
| G1ParScanThreadState* G1ParScanThreadStateSet::state_for_worker(uint worker_id) { |
| assert(worker_id < _n_workers, "out of bounds access"); |
| if (_states[worker_id] == NULL) { |
| _states[worker_id] = new G1ParScanThreadState(_g1h, worker_id, _young_cset_length); |
| } |
| return _states[worker_id]; |
| } |
| |
| const size_t* G1ParScanThreadStateSet::surviving_young_words() const { |
| assert(_flushed, "thread local state from the per thread states should have been flushed"); |
| return _surviving_young_words_total; |
| } |
| |
| void G1ParScanThreadStateSet::flush() { |
| assert(!_flushed, "thread local state from the per thread states should be flushed once"); |
| |
| for (uint worker_index = 0; worker_index < _n_workers; ++worker_index) { |
| G1ParScanThreadState* pss = _states[worker_index]; |
| |
| if (pss == NULL) { |
| continue; |
| } |
| |
| pss->flush(_surviving_young_words_total); |
| delete pss; |
| _states[worker_index] = NULL; |
| } |
| _flushed = true; |
| } |
| |
| oop G1ParScanThreadState::handle_evacuation_failure_par(oop old, markOop m) { |
| assert(_g1h->is_in_cset(old), "Object " PTR_FORMAT " should be in the CSet", p2i(old)); |
| |
| oop forward_ptr = old->forward_to_atomic(old, memory_order_relaxed); |
| if (forward_ptr == NULL) { |
| // Forward-to-self succeeded. We are the "owner" of the object. |
| HeapRegion* r = _g1h->heap_region_containing(old); |
| |
| if (!r->evacuation_failed()) { |
| r->set_evacuation_failed(true); |
| _g1h->hr_printer()->evac_failure(r); |
| } |
| |
| _g1h->preserve_mark_during_evac_failure(_worker_id, old, m); |
| |
| _scanner.set_region(r); |
| old->oop_iterate_backwards(&_scanner); |
| |
| return old; |
| } else { |
| // Forward-to-self failed. Either someone else managed to allocate |
| // space for this object (old != forward_ptr) or they beat us in |
| // self-forwarding it (old == forward_ptr). |
| assert(old == forward_ptr || !_g1h->is_in_cset(forward_ptr), |
| "Object " PTR_FORMAT " forwarded to: " PTR_FORMAT " " |
| "should not be in the CSet", |
| p2i(old), p2i(forward_ptr)); |
| return forward_ptr; |
| } |
| } |
| G1ParScanThreadStateSet::G1ParScanThreadStateSet(G1CollectedHeap* g1h, uint n_workers, size_t young_cset_length) : |
| _g1h(g1h), |
| _states(NEW_C_HEAP_ARRAY(G1ParScanThreadState*, n_workers, mtGC)), |
| _surviving_young_words_total(NEW_C_HEAP_ARRAY(size_t, young_cset_length, mtGC)), |
| _young_cset_length(young_cset_length), |
| _n_workers(n_workers), |
| _flushed(false) { |
| for (uint i = 0; i < n_workers; ++i) { |
| _states[i] = NULL; |
| } |
| memset(_surviving_young_words_total, 0, young_cset_length * sizeof(size_t)); |
| } |
| |
| G1ParScanThreadStateSet::~G1ParScanThreadStateSet() { |
| assert(_flushed, "thread local state from the per thread states should have been flushed"); |
| FREE_C_HEAP_ARRAY(G1ParScanThreadState*, _states); |
| FREE_C_HEAP_ARRAY(size_t, _surviving_young_words_total); |
| } |
