annotate src/share/vm/services/memoryUsage.hpp @ 452:00b023ae2d78

6722113: CMS: Incorrect overflow handling during precleaning of Reference lists Summary: When we encounter marking stack overflow during precleaning of Reference lists, we were using the overflow list mechanism, which can cause problems on account of mutating the mark word of the header because of conflicts with mutator accesses and updates of that field. Instead we should use the usual mechanism for overflow handling in concurrent phases, namely dirtying of the card on which the overflowed object lies. Since precleaning effectively does a form of discovered list processing, albeit with discovery enabled, we needed to adjust some code to be correct in the face of interleaved processing and discovery. Reviewed-by: apetrusenko, jcoomes
author ysr
date Thu, 20 Nov 2008 12:27:41 -0800
parents a61af66fc99e
children c18cbe5936b8
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1 /*
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2 * Copyright 2003-2005 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 memory usage contains the following attributes about memory usage:
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26 // initSize - represents the initial amount of memory (in bytes) that
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27 // the Java virtual machine requests from the operating system
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28 // for memory management. The Java virtual machine may request
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29 // additional memory from the operating system later when appropriate.
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30 // Its value may be undefined.
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31 // used - represents the amount of memory currently used (in bytes).
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32 // committed - represents the amount of memory (in bytes) that is
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33 // guaranteed to be available for use by the Java virtual machine.
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34 // The amount of committed memory may change over time (increase
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35 // or decrease). It is guaranteed to be greater than or equal
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36 // to initSize.
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37 // maxSize - represents the maximum amount of memory (in bytes)
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38 // that can be used for memory management. The maximum amount of
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39 // memory for memory management could be less than the amount of
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40 // committed memory. Its value may be undefined.
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41
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42 class MemoryUsage VALUE_OBJ_CLASS_SPEC {
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43 private:
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44 size_t _initSize;
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45 size_t _used;
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46 size_t _committed;
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47 size_t _maxSize;
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48
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49 public:
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50 // Constructors
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51 MemoryUsage(size_t i, size_t u, size_t c, size_t m) :
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52 _initSize(i), _used(u), _committed(c), _maxSize(m) {};
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53 MemoryUsage() :
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54 _initSize(0), _used(0), _committed(0), _maxSize(0) {};
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55
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56 size_t init_size() const { return _initSize; }
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57 size_t used() const { return _used; }
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58 size_t committed() const { return _committed; }
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59 size_t max_size() const { return _maxSize; }
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60
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61 inline static jlong convert_to_jlong(size_t val) {
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62 // In the 64-bit vm, a size_t can overflow a jlong (which is signed).
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63 jlong ret;
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64 if (val == (size_t)-1) {
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65 ret = -1L;
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66 } else {
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67 NOT_LP64(ret = val;)
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68 LP64_ONLY(ret = MIN2(val, (size_t)max_jlong);)
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69 }
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70 return ret;
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71 }
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72
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73 jlong init_size_as_jlong() const { return convert_to_jlong(_initSize); }
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74 jlong used_as_jlong() const { return convert_to_jlong(_used); }
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75 jlong committed_as_jlong() const { return convert_to_jlong(_committed); }
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76 jlong max_size_as_jlong() const { return convert_to_jlong(_maxSize); }
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77 };