1 /*

     2  * Copyright 2001-2007 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 // The Concurrent ZF Thread.  Performs concurrent zero-filling.

    26 

    27 class ConcurrentZFThread: public ConcurrentGCThread {

    28   friend class VMStructs;

    29   friend class ZeroFillRegionClosure;

    30 

    31  private:

    32 

    33   // Zero fill the heap region.

    34   void processHeapRegion(HeapRegion* r);

    35 

    36   // Stats

    37   //   Allocation (protected by heap lock).

    38   static int _region_allocs;  // Number of regions allocated

    39   static int _sync_zfs;       //   Synchronous zero-fills +

    40   static int _zf_waits;      //   Wait for conc zero-fill completion.

    41 

    42   // Number of regions CFZ thread fills.

    43   static int _regions_filled;

    44 

    45   COTracker _co_tracker;

    46 

    47   double _vtime_start;  // Initial virtual time.

    48 

    49   // These are static because the "print_summary_info" method is, and

    50   // it currently assumes there is only one ZF thread.  We'll change when

    51   // we need to.

    52   static double _vtime_accum;  // Initial virtual time.

    53   static double vtime_accum() { return _vtime_accum; }

    54 

    55   // Offer yield for GC.  Returns true if yield occurred.

    56   bool offer_yield();

    57 

    58  public:

    59   // Constructor

    60   ConcurrentZFThread();

    61 

    62   // Main loop.

    63   virtual void run();

    64 

    65   // Printing

    66   void print();

    67 

    68   // Waits until "r" has been zero-filled.  Requires caller to hold the

    69   // ZF_mon.

    70   static void wait_for_ZF_completed(HeapRegion* r);

    71 

    72   // Get or clear the current unclean region.  Should be done

    73   // while holding the ZF_needed_mon lock.

    74 

    75   // shutdown

    76   static void stop();

    77 

    78   // Stats

    79   static void note_region_alloc() {_region_allocs++; }

    80   static void note_sync_zfs() { _sync_zfs++; }

    81   static void note_zf_wait() { _zf_waits++; }

    82   static void note_region_filled() { _regions_filled++; }

    83 

    84   static void print_summary_info();

    85 };