jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/parallelScavenge/prefetchQueue.hpp@82db0859acbe

6642862: Code cache allocation fails with large pages after 6588638
Reviewed-by: apetrusenko

     1 /*

     2  * Copyright 2002-2003 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  */

    25 //

    26 // PrefetchQueue is a FIFO queue of variable length (currently 8).

    27 //

    28 // We need to examine the performance penalty of variable lengths.

    29 // We may also want to split this into cpu dependant bits.

    30 //

    32 const int PREFETCH_QUEUE_SIZE  = 8;

    34 class PrefetchQueue : public CHeapObj {

    35  private:

    36   oop*                         _prefetch_queue[PREFETCH_QUEUE_SIZE];

    37   unsigned int                 _prefetch_index;

    39  public:

    40   int length() { return PREFETCH_QUEUE_SIZE; }

    42   inline void clear() {

    43     for(int i=0; i<PREFETCH_QUEUE_SIZE; i++) {

    44       _prefetch_queue[i] = NULL;

    45     }

    46     _prefetch_index = 0;

    47   }

    49   inline oop* push_and_pop(oop* p) {

    50     Prefetch::write((*p)->mark_addr(), 0);

    51     // This prefetch is intended to make sure the size field of array

    52     // oops is in cache. It assumes the the object layout is

    53     // mark -> klass -> size, and that mark and klass are heapword

    54     // sized. If this should change, this prefetch will need updating!

    55     Prefetch::write((*p)->mark_addr() + (HeapWordSize*2), 0);

    56     _prefetch_queue[_prefetch_index++] = p;

    57     _prefetch_index &= (PREFETCH_QUEUE_SIZE-1);

    58     return _prefetch_queue[_prefetch_index];

    59   }

    61   // Stores a NULL pointer in the pop'd location.

    62   inline oop* pop() {

    63     _prefetch_queue[_prefetch_index++] = NULL;

    64     _prefetch_index &= (PREFETCH_QUEUE_SIZE-1);

    65     return _prefetch_queue[_prefetch_index];

    66   }

    67 };

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