1 /*

     2  * Copyright (c) 2001, 2010, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 

    25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTZFTHREAD_HPP

    26 #define SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTZFTHREAD_HPP

    27 

    28 #include "gc_implementation/shared/concurrentGCThread.hpp"

    29 

    30 // The Concurrent ZF Thread.  Performs concurrent zero-filling.

    31 

    32 class ConcurrentZFThread: public ConcurrentGCThread {

    33   friend class VMStructs;

    34   friend class ZeroFillRegionClosure;

    35 

    36  private:

    37 

    38   // Zero fill the heap region.

    39   void processHeapRegion(HeapRegion* r);

    40 

    41   // Stats

    42   //   Allocation (protected by heap lock).

    43   static int _region_allocs;  // Number of regions allocated

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

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

    46 

    47   // Number of regions CFZ thread fills.

    48   static int _regions_filled;

    49 

    50   double _vtime_start;  // Initial virtual time.

    51 

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

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

    54   // we need to.

    55   static double _vtime_accum;  // Initial virtual time.

    56   static double vtime_accum() { return _vtime_accum; }

    57 

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

    59   bool offer_yield();

    60 

    61  public:

    62   // Constructor

    63   ConcurrentZFThread();

    64 

    65   // Main loop.

    66   virtual void run();

    67 

    68   // Printing

    69   void print_on(outputStream* st) const;

    70   void print() const;

    71 

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

    73   // ZF_mon.

    74   static void wait_for_ZF_completed(HeapRegion* r);

    75 

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

    77   // while holding the ZF_needed_mon lock.

    78 

    79   // shutdown

    80   void stop();

    81 

    82   // Stats

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

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

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

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

    87 

    88   static void print_summary_info();

    89 };

    90 

    91 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTZFTHREAD_HPP