/*

 * 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.

 *

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 */

#ifndef SHARE_VM_RUNTIME_SWEEPER_HPP

#define SHARE_VM_RUNTIME_SWEEPER_HPP

// An NmethodSweeper is an incremental cleaner for:

//    - cleanup inline caches

//    - reclamation of unreferences zombie nmethods

//

class NMethodSweeper : public AllStatic {

  static long      _traversals;   // Stack traversal count

  static nmethod*  _current;      // Current nmethod

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

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

  static volatile int      _sweep_started; // Flag to control conc sweeper

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

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

  static bool      _do_sweep;        // Flag to skip the conc sweep if no stack scan happened

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

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

  static bool      _was_full;        // remember if we did emergency unloading

  static jint      _advise_to_sweep; // flag to indicate code cache getting full

  static jlong     _last_was_full;   // timestamp of last emergency unloading

  static uint      _highest_marked;   // highest compile id dumped at last emergency unloading

  static long      _was_full_traversal;   // trav number at last emergency unloading

  static void process_nmethod(nmethod *nm);

  static void log_sweep(const char* msg, const char* format = NULL, ...);

 public:

  static long traversal_count() { return _traversals; }

#ifdef ASSERT

  // Keep track of sweeper activity in the ring buffer

  static void record_sweep(nmethod* nm, int line);

  static void report_events(int id, address entry);

  static void report_events();

#endif

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

  static void sweep_code_cache(); // Concurrent part of sweep job

  static void possibly_sweep();   // Compiler threads call this to sweep

  static void notify(nmethod* nm) {

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

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

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

     _rescan = true;

  }

  static void handle_full_code_cache(bool is_full); // Called by compilers who fail to allocate

  static void speculative_disconnect_nmethods(bool was_full);   // Called by vm op to deal with alloc failure

  static void set_was_full(bool state) { _was_full = state; }

  static bool was_full() { return _was_full; }

};

#endif // SHARE_VM_RUNTIME_SWEEPER_HPP