view src/share/vm/gc_implementation/concurrentMarkSweep/freeChunk.cpp @ 1951:899bbbdcb6ea

6997298: fatal error: must own lock CMS_markBitMap_lock during heap dump Summary: Since we are at a stop-world pause, the existing CMS-phase checks are sufficient for safety, and the locking check can be safely elided. Elaborated documentation comment to the case where class unloading and verification are disabled, and the query happens when we aren't in the sweeping phase, where the answer "false" would be (almost everywhere) too pessimistic. Reviewed-by: jmasa, johnc, tonyp
author ysr
date Fri, 05 Nov 2010 13:20:37 -0700
parents c18cbe5936b8
children f95d63e2154a
line wrap: on
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/*
 * Copyright (c) 2001, 2008, 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
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 */

# include "incls/_precompiled.incl"
# include "incls/_freeChunk.cpp.incl"

#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",
    next(), prev(), cantCoalesce() ? "[can't coalesce]" : "");
}