1 /* 2 * Copyright (c) 2001, 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 25 #include "precompiled.hpp" 26 #include "gc/cms/freeChunk.hpp" 27 #include "utilities/copy.hpp" 28 29 #ifndef PRODUCT 30 31 #define baadbabeHeapWord badHeapWordVal 32 #define deadbeefHeapWord 0xdeadbeef 33 34 size_t const FreeChunk::header_size() { 35 return sizeof(FreeChunk)/HeapWordSize; 36 } 37 38 void FreeChunk::mangleAllocated(size_t size) { 39 // mangle all but the header of a just-allocated block 40 // of storage 41 assert(size >= MinChunkSize, "smallest size of object"); 42 // we can't assert that _size == size because this may be an 43 // allocation out of a linear allocation block 44 assert(sizeof(FreeChunk) % HeapWordSize == 0, 45 "shouldn't write beyond chunk"); 46 HeapWord* addr = (HeapWord*)this; 47 size_t hdr = header_size(); 48 Copy::fill_to_words(addr + hdr, size - hdr, baadbabeHeapWord); 49 } 50 51 void FreeChunk::mangleFreed(size_t sz) { 52 assert(baadbabeHeapWord != deadbeefHeapWord, "Need distinct patterns"); 53 // mangle all but the header of a just-freed block of storage 54 // just prior to passing it to the storage dictionary 55 assert(sz >= MinChunkSize, "smallest size of object"); 56 assert(sz == size(), "just checking"); 57 HeapWord* addr = (HeapWord*)this; 58 size_t hdr = header_size(); 59 Copy::fill_to_words(addr + hdr, sz - hdr, deadbeefHeapWord); 60 } 61 62 void FreeChunk::verifyList() const { 63 FreeChunk* nextFC = next(); 64 if (nextFC != NULL) { 65 assert(this == nextFC->prev(), "broken chain"); 66 assert(size() == nextFC->size(), "wrong size"); 67 nextFC->verifyList(); 68 } 69 } 70 #endif 71 72 void FreeChunk::print_on(outputStream* st) { 73 st->print_cr("Next: " PTR_FORMAT " Prev: " PTR_FORMAT " %s", 74 p2i(next()), p2i(prev()), cantCoalesce() ? "[can't coalesce]" : ""); 75 }