view src/share/vm/oops/markOop.cpp @ 5863:935cc67fbbf9

Added tag jdk7u241-ga for changeset c6a8482b1d38
author andrew
date Wed, 16 Oct 2019 13:45:47 +0100
parents f08d439fab8c
line wrap: on
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 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
 * 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 if you need additional information or have any
 * questions.

#include "precompiled.hpp"
#include "oops/markOop.hpp"
#ifdef TARGET_OS_FAMILY_linux
# include "thread_linux.inline.hpp"
#ifdef TARGET_OS_FAMILY_solaris
# include "thread_solaris.inline.hpp"
#ifdef TARGET_OS_FAMILY_windows
# include "thread_windows.inline.hpp"
# include "thread_aix.inline.hpp"
# include "thread_bsd.inline.hpp"

void markOopDesc::print_on(outputStream* st) const {
  if (is_locked()) {
    st->print("locked(0x%lx)->", value());
  } else {
    assert(is_unlocked() || has_bias_pattern(), "just checking");
    if (has_bias_pattern())  st->print("biased,");
    st->print("hash %#lx,", hash());
    st->print("age %d)", age());

// Give advice about whether the oop that contains this markOop
// should be cached or not.
bool markOopDesc::should_not_be_cached() const {
  // the cast is because decode_pointer() isn't marked const
  if (is_marked() && ((markOopDesc *)this)->decode_pointer() != NULL) {
    // If the oop containing this markOop is being forwarded, then
    // we are in the middle of GC and we do not want the containing
    // oop to be added to a cache. We have no way of knowing whether
    // the cache has already been visited by the current GC phase so
    // we don't know whether the forwarded oop will be properly
    // processed in this phase. If the forwarded oop is not properly
    // processed, then we'll see strange crashes or asserts during
    // the next GC run because the markOop will contain an unexpected
    // value.
    // This situation has been seen when we are GC'ing a methodOop
    // because we use the methodOop while we're GC'ing it. Scary
    // stuff. Some of the uses the methodOop cause the methodOop to
    // be added to the OopMapCache in the instanceKlass as a side
    // effect. This check lets the cache maintainer know when a
    // cache addition would not be safe.
    return true;

  // caching the containing oop should be just fine
  return false;