src/hotspot/share/gc/cms/freeChunk.cpp
changeset 47216 71c04702a3d5
parent 46674 a9e42ff6158f
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/cms/freeChunk.cpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2001, 2017, 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.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc/cms/freeChunk.hpp"
+#include "utilities/copy.hpp"
+
+#ifndef PRODUCT
+
+#define baadbabeHeapWord badHeapWordVal
+#define deadbeefHeapWord 0xdeadbeef
+
+size_t const FreeChunk::header_size() {
+  return sizeof(FreeChunk)/HeapWordSize;
+}
+
+void FreeChunk::mangleAllocated(size_t size) {
+  // mangle all but the header of a just-allocated block
+  // of storage
+  assert(size >= MinChunkSize, "smallest size of object");
+  // we can't assert that _size == size because this may be an
+  // allocation out of a linear allocation block
+  assert(sizeof(FreeChunk) % HeapWordSize == 0,
+         "shouldn't write beyond chunk");
+  HeapWord* addr = (HeapWord*)this;
+  size_t hdr = header_size();
+  Copy::fill_to_words(addr + hdr, size - hdr, baadbabeHeapWord);
+}
+
+void FreeChunk::mangleFreed(size_t sz) {
+  assert(baadbabeHeapWord != deadbeefHeapWord, "Need distinct patterns");
+  // mangle all but the header of a just-freed block of storage
+  // just prior to passing it to the storage dictionary
+  assert(sz >= MinChunkSize, "smallest size of object");
+  assert(sz == size(), "just checking");
+  HeapWord* addr = (HeapWord*)this;
+  size_t hdr = header_size();
+  Copy::fill_to_words(addr + hdr, sz - hdr, deadbeefHeapWord);
+}
+
+void FreeChunk::verifyList() const {
+  FreeChunk* nextFC = next();
+  if (nextFC != NULL) {
+    assert(this == nextFC->prev(), "broken chain");
+    assert(size() == nextFC->size(), "wrong size");
+    nextFC->verifyList();
+  }
+}
+#endif
+
+void FreeChunk::print_on(outputStream* st) {
+  st->print_cr("Next: " PTR_FORMAT " Prev: " PTR_FORMAT " %s",
+    p2i(next()), p2i(prev()), cantCoalesce() ? "[can't coalesce]" : "");
+}