annotate src/share/vm/memory/watermark.hpp @ 453:c96030fff130

6684579: SoftReference processing can be made more efficient Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not. Reviewed-by: jmasa
author ysr
date Thu, 20 Nov 2008 16:56:09 -0800
parents a61af66fc99e
children c18cbe5936b8
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1 /*
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2 * Copyright 2000-2001 Sun Microsystems, Inc. All Rights Reserved.
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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4 *
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5 * This code is free software; you can redistribute it and/or modify it
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6 * under the terms of the GNU General Public License version 2 only, as
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7 * published by the Free Software Foundation.
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8 *
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9 * This code is distributed in the hope that it will be useful, but WITHOUT
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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12 * version 2 for more details (a copy is included in the LICENSE file that
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13 * accompanied this code).
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14 *
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15 * You should have received a copy of the GNU General Public License version
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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18 *
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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20 * CA 95054 USA or visit www.sun.com if you need additional information or
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21 * have any questions.
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22 *
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23 */
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24
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25 // A water mark points into a space and is used during GC to keep track of
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26 // progress.
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27
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28 class Space;
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29
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30 class WaterMark VALUE_OBJ_CLASS_SPEC {
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31 friend class VMStructs;
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32 private:
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33 HeapWord* _point;
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34 Space* _space;
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35 public:
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36 // Accessors
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37 Space* space() const { return _space; }
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38 void set_space(Space* s) { _space = s; }
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39 HeapWord* point() const { return _point; }
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40 void set_point(HeapWord* p) { _point = p; }
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41
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42 // Constructors
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43 WaterMark(Space* s, HeapWord* p) : _space(s), _point(p) {};
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44 WaterMark() : _space(NULL), _point(NULL) {};
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45 };
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46
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47 inline bool operator==(const WaterMark& x, const WaterMark& y) {
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48 return (x.point() == y.point()) && (x.space() == y.space());
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49 }
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50
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51 inline bool operator!=(const WaterMark& x, const WaterMark& y) {
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52 return !(x == y);
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53 }