jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/concurrentG1Refine.hpp@e7d0505c8a30

8059758: Footprint regressions with JDK-8038423
Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso

     1 /*

     2  * Copyright (c) 2001, 2013, 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  */

    25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINE_HPP

    26 #define SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINE_HPP

    28 #include "gc_implementation/g1/g1HotCardCache.hpp"

    29 #include "memory/allocation.hpp"

    30 #include "runtime/thread.hpp"

    31 #include "utilities/globalDefinitions.hpp"

    33 // Forward decl

    34 class ConcurrentG1RefineThread;

    35 class G1CollectedHeap;

    36 class G1HotCardCache;

    37 class G1RegionToSpaceMapper;

    38 class G1RemSet;

    39 class DirtyCardQueue;

    41 class ConcurrentG1Refine: public CHeapObj<mtGC> {

    42   ConcurrentG1RefineThread** _threads;

    43   uint _n_threads;

    44   uint _n_worker_threads;

    45  /*

    46   * The value of the update buffer queue length falls into one of 3 zones:

    47   * green, yellow, red. If the value is in [0, green) nothing is

    48   * done, the buffers are left unprocessed to enable the caching effect of the

    49   * dirtied cards. In the yellow zone [green, yellow) the concurrent refinement

    50   * threads are gradually activated. In [yellow, red) all threads are

    51   * running. If the length becomes red (max queue length) the mutators start

    52   * processing the buffers.

    53   *

    54   * There are some interesting cases (when G1UseAdaptiveConcRefinement

    55   * is turned off):

    56   * 1) green = yellow = red = 0. In this case the mutator will process all

    57   *    buffers. Except for those that are created by the deferred updates

    58   *    machinery during a collection.

    59   * 2) green = 0. Means no caching. Can be a good way to minimize the

    60   *    amount of time spent updating rsets during a collection.

    61   */

    62   int _green_zone;

    63   int _yellow_zone;

    64   int _red_zone;

    66   int _thread_threshold_step;

    68   // We delay the refinement of 'hot' cards using the hot card cache.

    69   G1HotCardCache _hot_card_cache;

    71   // Reset the threshold step value based of the current zone boundaries.

    72   void reset_threshold_step();

    74  public:

    75   ConcurrentG1Refine(G1CollectedHeap* g1h, CardTableEntryClosure* refine_closure);

    76   ~ConcurrentG1Refine();

    78   void init(G1RegionToSpaceMapper* card_counts_storage);

    79   void stop();

    81   void reinitialize_threads();

    83   // Iterate over all concurrent refinement threads

    84   void threads_do(ThreadClosure *tc);

    86   // Iterate over all worker refinement threads

    87   void worker_threads_do(ThreadClosure * tc);

    89   // The RS sampling thread

    90   ConcurrentG1RefineThread * sampling_thread() const;

    92   static uint thread_num();

    94   void print_worker_threads_on(outputStream* st) const;

    96   void set_green_zone(int x)  { _green_zone = x;  }

    97   void set_yellow_zone(int x) { _yellow_zone = x; }

    98   void set_red_zone(int x)    { _red_zone = x;    }

   100   int green_zone() const      { return _green_zone;  }

   101   int yellow_zone() const     { return _yellow_zone; }

   102   int red_zone() const        { return _red_zone;    }

   104   uint total_thread_num() const  { return _n_threads;        }

   105   uint worker_thread_num() const { return _n_worker_threads; }

   107   int thread_threshold_step() const { return _thread_threshold_step; }

   109   G1HotCardCache* hot_card_cache() { return &_hot_card_cache; }

   110 };

   112 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINE_HPP

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

src/share/vm/gc_implementation/g1/concurrentG1Refine.hpp@e7d0505c8a30

src/share/vm/gc_implementation/g1/concurrentG1Refine.hpp