1 /*

     2  * Copyright 1997-2005 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    24 

    25 // An NmethodSweeper is an incremental cleaner for:

    26 //    - cleanup inline caches

    27 //    - reclamation of unreferences zombie nmethods

    28 //

    29 

    30 class NMethodSweeper : public AllStatic {

    31   static long      _traversals;   // Stack traversal count

    32   static CodeBlob* _current;      // Current nmethod

    33   static int       _seen;         // Nof. nmethod we have currently processed in current pass of CodeCache

    34   static int       _invocations;  // No. of invocations left until we are completed with this pass

    35 

    36   static bool      _rescan;          // Indicates that we should do a full rescan of the

    37                                      // of the code cache looking for work to do.

    38   static int       _locked_seen;     // Number of locked nmethods encountered during the scan

    39   static int       _not_entrant_seen_on_stack; // Number of not entrant nmethod were are still on stack

    40 

    41 

    42   static void process_nmethod(nmethod *nm);

    43  public:

    44   static long traversal_count() { return _traversals; }

    45 

    46   static void sweep();  // Invoked at the end of each safepoint

    47 

    48   static void notify(nmethod* nm) {

    49     // Perform a full scan of the code cache from the beginning.  No

    50     // need to synchronize the setting of this flag since it only

    51     // changes to false at safepoint so we can never overwrite it with false.

    52      _rescan = true;

    53   }

    54 };