1 /* 2 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_PRESERVEMARKQUEUE_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_PRESERVEMARKQUEUE_HPP 27 28 #include "oops/oopsHierarchy.hpp" 29 30 struct G1PreserveMarkQueueEntry { 31 oop obj; 32 markOop mark; 33 }; 34 35 class G1PreserveMarkChunk; 36 37 class G1PreserveMarkQueue { 38 const size_t _initial_chunk_capacity; 39 const size_t _max_chunk_capacity; 40 size_t _current_capacity; 41 G1PreserveMarkChunk* _current_write_chunk; 42 G1PreserveMarkChunk* _current_read_chunk; 43 44 public: 45 G1PreserveMarkQueue(size_t initial_chunk_capacity, size_t max_chunk_capacity) : 46 _initial_chunk_capacity(initial_chunk_capacity), _max_chunk_capacity(max_chunk_capacity), 47 _current_write_chunk(NULL), _current_read_chunk(NULL) { 48 assert(_initial_chunk_capacity <= _max_chunk_capacity, "initial must be <= max"); 49 } 50 51 bool has_data(); 52 void append(const oop& obj, const markOop& mark); 53 G1PreserveMarkQueueEntry remove_first(); 54 55 size_t new_chunk_capacity() { 56 if (_current_write_chunk == NULL) { 57 _current_capacity = _initial_chunk_capacity; 58 } else if (_current_capacity == _max_chunk_capacity) { 59 // do nothing. already at max capacity 60 } else { 61 // Grow with 50%, similar to java.util.ArrayList 62 _current_capacity += _current_capacity >> 1; 63 _current_capacity = MIN2(_current_capacity, _max_chunk_capacity); 64 } 65 66 assert(_current_capacity >= _initial_chunk_capacity, "too small capacity"); 67 assert(_current_capacity <= _max_chunk_capacity, "too large capacity"); 68 69 return _current_capacity; 70 } 71 72 NOT_PRODUCT(void verify_empty()); 73 }; 74 75 NOT_PRODUCT(void g1PreserveMarkChunkTests()); 76 NOT_PRODUCT(void g1PreserveMarkQueueTests()); 77 78 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_PRESERVEMARKQUEUE_HPP