--- old/src/share/vm/gc_implementation/g1/g1ParScanThreadState.cpp 2014-12-16 11:06:37.046358688 +0100 +++ new/src/share/vm/gc_implementation/g1/g1ParScanThreadState.cpp 2014-12-16 11:06:36.983356858 +0100 @@ -38,6 +38,7 @@ _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); @@ -59,6 +60,12 @@ _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(); } @@ -150,52 +157,94 @@ } while (!_refs->is_empty()); } -oop G1ParScanThreadState::copy_to_survivor_space(oop const old, +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: %u", state.value())); + assert(dest->is_in_cset_or_humongous(), err_msg("Unexpected dest: %u", 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: %u", 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) { - size_t word_sz = old->size(); - HeapRegion* from_region = _g1h->heap_region_containing_raw(old); + const size_t word_sz = old->size(); + HeapRegion* const from_region = _g1h->heap_region_containing_raw(old); // +1 to make the -1 indexes valid... - int young_index = from_region->young_index_in_cset()+1; + 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" ); - G1CollectorPolicy* g1p = _g1h->g1_policy(); - uint age = old_mark->has_displaced_mark_helper() ? old_mark->displaced_mark_helper()->age() - : old_mark->age(); - GCAllocPurpose alloc_purpose = g1p->evacuation_destination(from_region, age, - word_sz); - AllocationContext_t context = from_region->allocation_context(); - HeapWord* obj_ptr = _g1_par_allocator->allocate(alloc_purpose, word_sz, context); -#ifndef PRODUCT - // Should this evacuation fail? - if (_g1h->evacuation_should_fail()) { - if (obj_ptr != NULL) { - _g1_par_allocator->undo_allocation(alloc_purpose, obj_ptr, word_sz, context); - obj_ptr = NULL; + 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); + } } } -#endif // !PRODUCT - if (obj_ptr == NULL) { - // This will either forward-to-self, or detect that someone else has - // installed a forwarding pointer. + 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); } - - oop obj = oop(obj_ptr); +#endif // !PRODUCT // We're going to allocate linearly, so might as well prefetch ahead. Prefetch::write(obj_ptr, PrefetchCopyIntervalInBytes); - oop forward_ptr = old->forward_to_atomic(obj); + 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); - // alloc_purpose is just a hint to allocate() above, recheck the type of region - // we actually allocated from and update alloc_purpose accordingly - HeapRegion* to_region = _g1h->heap_region_containing_raw(obj_ptr); - alloc_purpose = to_region->is_young() ? GCAllocForSurvived : GCAllocForTenured; - - if (g1p->track_object_age(alloc_purpose)) { + if (dest_state.is_young()) { if (age < markOopDesc::max_age) { age++; } @@ -215,13 +264,19 @@ } if (G1StringDedup::is_enabled()) { - G1StringDedup::enqueue_from_evacuation(from_region->is_young(), - to_region->is_young(), + 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* surv_young_words = surviving_young_words(); + size_t* const surv_young_words = surviving_young_words(); surv_young_words[young_index] += word_sz; if (obj->is_objArray() && arrayOop(obj)->length() >= ParGCArrayScanChunk) { @@ -232,14 +287,13 @@ oop* old_p = set_partial_array_mask(old); push_on_queue(old_p); } else { - // No point in using the slower heap_region_containing() method, - // given that we know obj is in the heap. - _scanner.set_region(_g1h->heap_region_containing_raw(obj)); + 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(alloc_purpose, obj_ptr, word_sz, context); - obj = forward_ptr; + _g1_par_allocator->undo_allocation(dest_state, obj_ptr, word_sz, context); + return forward_ptr; } - return obj; }