| /* |
| * Copyright (c) 2001, 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. |
| * |
| */ |
| |
| #ifndef SHARE_VM_GC_G1_G1CARDTABLE_HPP |
| #define SHARE_VM_GC_G1_G1CARDTABLE_HPP |
| |
| #include "gc/g1/g1RegionToSpaceMapper.hpp" |
| #include "gc/shared/cardTable.hpp" |
| #include "oops/oopsHierarchy.hpp" |
| #include "utilities/macros.hpp" |
| |
| class G1CardTable; |
| class G1RegionToSpaceMapper; |
| |
| class G1CardTableChangedListener : public G1MappingChangedListener { |
| private: |
| G1CardTable* _card_table; |
| public: |
| G1CardTableChangedListener() : _card_table(NULL) { } |
| |
| void set_card_table(G1CardTable* card_table) { _card_table = card_table; } |
| |
| virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled); |
| }; |
| |
| class G1CardTable: public CardTable { |
| friend class VMStructs; |
| friend class G1CardTableChangedListener; |
| |
| G1CardTableChangedListener _listener; |
| |
| enum G1CardValues { |
| g1_young_gen = CT_MR_BS_last_reserved << 1 |
| }; |
| |
| public: |
| G1CardTable(MemRegion whole_heap): CardTable(whole_heap, /* scanned concurrently */ true), _listener() { |
| _listener.set_card_table(this); |
| } |
| bool is_card_dirty(size_t card_index) { |
| return _byte_map[card_index] == dirty_card_val(); |
| } |
| |
| static jbyte g1_young_card_val() { return g1_young_gen; } |
| |
| /* |
| Claimed and deferred bits are used together in G1 during the evacuation |
| pause. These bits can have the following state transitions: |
| 1. The claimed bit can be put over any other card state. Except that |
| the "dirty -> dirty and claimed" transition is checked for in |
| G1 code and is not used. |
| 2. Deferred bit can be set only if the previous state of the card |
| was either clean or claimed. mark_card_deferred() is wait-free. |
| We do not care if the operation is be successful because if |
| it does not it will only result in duplicate entry in the update |
| buffer because of the "cache-miss". So it's not worth spinning. |
| */ |
| |
| bool is_card_claimed(size_t card_index) { |
| jbyte val = _byte_map[card_index]; |
| return (val & (clean_card_mask_val() | claimed_card_val())) == claimed_card_val(); |
| } |
| |
| inline void set_card_claimed(size_t card_index); |
| |
| void verify_g1_young_region(MemRegion mr) PRODUCT_RETURN; |
| void g1_mark_as_young(const MemRegion& mr); |
| |
| bool mark_card_deferred(size_t card_index); |
| |
| bool is_card_deferred(size_t card_index) { |
| jbyte val = _byte_map[card_index]; |
| return (val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val(); |
| } |
| |
| static size_t compute_size(size_t mem_region_size_in_words) { |
| size_t number_of_slots = (mem_region_size_in_words / card_size_in_words); |
| return ReservedSpace::allocation_align_size_up(number_of_slots); |
| } |
| |
| // Returns how many bytes of the heap a single byte of the Card Table corresponds to. |
| static size_t heap_map_factor() { return card_size; } |
| |
| void initialize() {} |
| void initialize(G1RegionToSpaceMapper* mapper); |
| |
| virtual void resize_covered_region(MemRegion new_region) { ShouldNotReachHere(); } |
| |
| virtual bool is_in_young(oop obj) const; |
| }; |
| |
| #endif // SHARE_VM_GC_G1_G1CARDTABLE_HPP |