1 /* 2 * Copyright (c) 2015, 2017, 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 #include "precompiled.hpp" 25 #include "gc/z/zForwardingTable.inline.hpp" 26 #include "gc/z/zUtils.inline.hpp" 27 #include "memory/allocation.inline.hpp" 28 #include "utilities/debug.hpp" 29 30 void ZForwardingTable::setup(size_t live_objects) { 31 assert(is_null(), "Should be empty"); 32 assert(live_objects > 0, "Invalid size"); 33 34 // Allocate table for linear probing. The size of the table must be 35 // a power of two to allow for quick and inexpensive indexing/masking. 36 // The table is sized to have a load factor of 50%, i.e. sized to have 37 // double the number of entries actuallly inserted. 38 _size = ZUtils::round_up_power_of_2(live_objects * 2); 39 _table = MallocArrayAllocator<ZForwardingTableEntry>::allocate(_size, mtGC); 40 41 // Clear table 42 memset(_table, ZForwardingTableEntry::empty(), _size * sizeof(ZForwardingTableEntry)); 43 } 44 45 void ZForwardingTable::reset() { 46 // Free table 47 MallocArrayAllocator<ZForwardingTableEntry>::free(_table); 48 _table = NULL; 49 _size = 0; 50 } 51 52 void ZForwardingTable::verify(size_t object_max_count, size_t live_objects) const { 53 size_t count = 0; 54 55 for (size_t i = 0; i < _size; i++) { 56 const ZForwardingTableEntry entry = _table[i]; 57 if (entry.is_empty()) { 58 // Skip empty entries 59 continue; 60 } 61 62 // Check from index 63 guarantee(entry.from_index() < object_max_count, "Invalid from index"); 64 65 // Check for duplicates 66 for (size_t j = i + 1; j < _size; j++) { 67 const ZForwardingTableEntry other = _table[j]; 68 guarantee(entry.from_index() != other.from_index(), "Duplicate from"); 69 guarantee(entry.to_offset() != other.to_offset(), "Duplicate to"); 70 } 71 72 count++; 73 } 74 75 // Check number of non-null entries 76 guarantee(live_objects == count, "Count mismatch"); 77 }