Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 1997, 2010, 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 "oops/markOop.hpp"

 #ifdef TARGET_OS_FAMILY_linux

 # include "thread_linux.inline.hpp"

 #endif

 #ifdef TARGET_OS_FAMILY_solaris

 # include "thread_solaris.inline.hpp"

 #endif

 #ifdef TARGET_OS_FAMILY_windows

 # include "thread_windows.inline.hpp"

 #endif

 void markOopDesc::print_on(outputStream* st) const {

   if (is_locked()) {

     st->print("locked(0x%lx)->", value());

     markOop(*(markOop*)value())->print_on(st);

   } else {

     assert(is_unlocked() || has_bias_pattern(), "just checking");

     st->print("mark(");

     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;

 }