src/share/vm/gc_implementation/parallelScavenge/prefetchQueue.hpp

Fri, 27 Feb 2009 13:27:09 -0800

author
twisti
date
Fri, 27 Feb 2009 13:27:09 -0800
changeset 1040
98cb887364d3
parent 631
d1605aabd0a1
child 1907
c18cbe5936b8
permissions
-rw-r--r--

6810672: Comment typos
Summary: I have collected some typos I have found while looking at the code.
Reviewed-by: kvn, never

     1 /*
     2  * Copyright 2002-2008 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 dependent bits.
    30 //
    32 const int PREFETCH_QUEUE_SIZE  = 8;
    34 class PrefetchQueue : public CHeapObj {
    35  private:
    36   void* _prefetch_queue[PREFETCH_QUEUE_SIZE];
    37   uint  _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   template <class T> inline void* push_and_pop(T* p) {
    50     oop o = oopDesc::load_decode_heap_oop_not_null(p);
    51     Prefetch::write(o->mark_addr(), 0);
    52     // This prefetch is intended to make sure the size field of array
    53     // oops is in cache. It assumes the the object layout is
    54     // mark -> klass -> size, and that mark and klass are heapword
    55     // sized. If this should change, this prefetch will need updating!
    56     Prefetch::write(o->mark_addr() + (HeapWordSize*2), 0);
    57     _prefetch_queue[_prefetch_index++] = p;
    58     _prefetch_index &= (PREFETCH_QUEUE_SIZE-1);
    59     return _prefetch_queue[_prefetch_index];
    60   }
    62   // Stores a NULL pointer in the pop'd location.
    63   inline void* pop() {
    64     _prefetch_queue[_prefetch_index++] = NULL;
    65     _prefetch_index &= (PREFETCH_QUEUE_SIZE-1);
    66     return _prefetch_queue[_prefetch_index];
    67   }
    68 };

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