1 /* 2 * Copyright (c) 2015, 2019, 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/zForwarding.inline.hpp" 26 #include "gc/z/zPage.inline.hpp" 27 #include "gc/z/zUtils.inline.hpp" 28 #include "memory/allocation.hpp" 29 #include "utilities/debug.hpp" 30 31 ZForwarding* ZForwarding::create(ZPage* page) { 32 // Allocate table for linear probing. The size of the table must be 33 // a power of two to allow for quick and inexpensive indexing/masking. 34 // The table is sized to have a load factor of 50%, i.e. sized to have 35 // double the number of entries actually inserted. 36 assert(page->live_objects() > 0, "Invalid value"); 37 const uint32_t nentries = ZUtils::round_up_power_of_2(page->live_objects() * 2); 38 return ::new (AttachedArray::alloc(nentries)) ZForwarding(page, nentries); 39 } 40 41 void ZForwarding::destroy(ZForwarding* forwarding) { 42 AttachedArray::free(forwarding); 43 } 44 45 ZForwarding::ZForwarding(ZPage* page, uint32_t nentries) : 46 _virtual(page->virtual_memory()), 47 _object_alignment_shift(page->object_alignment_shift()), 48 _entries(nentries), 49 _page(page), 50 _refcount(1), 51 _pinned(false) {} 52 53 void ZForwarding::verify() const { 54 guarantee(_refcount > 0, "Invalid refcount"); 55 guarantee(_page != NULL, "Invalid page"); 56 57 uint32_t live_objects = 0; 58 59 for (ZForwardingCursor i = 0; i < _entries.length(); i++) { 60 const ZForwardingEntry entry = at(&i); 61 if (entry.is_empty()) { 62 // Skip empty entries 63 continue; 64 } 65 66 // Check from index 67 guarantee(entry.from_index() < _page->object_max_count(), "Invalid from index"); 68 69 // Check for duplicates 70 for (ZForwardingCursor j = i + 1; j < _entries.length(); j++) { 71 const ZForwardingEntry other = at(&j); 72 guarantee(entry.from_index() != other.from_index(), "Duplicate from"); 73 guarantee(entry.to_offset() != other.to_offset(), "Duplicate to"); 74 } 75 76 live_objects++; 77 } 78 79 // Check number of non-empty entries 80 guarantee(live_objects == _page->live_objects(), "Invalid number of entries"); 81 }