Mercurial > hg > graal-compiler
comparison src/share/vm/gc_implementation/concurrentMarkSweep/freeBlockDictionary.hpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | 790e66e5fbac |
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1 /* | |
2 * Copyright 2001-2005 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 */ | |
24 | |
25 // | |
26 // Free block maintenance for Concurrent Mark Sweep Generation | |
27 // | |
28 // The main data structure for free blocks are | |
29 // . an indexed array of small free blocks, and | |
30 // . a dictionary of large free blocks | |
31 // | |
32 | |
33 // No virtuals in FreeChunk (don't want any vtables). | |
34 | |
35 // A FreeChunk is merely a chunk that can be in a doubly linked list | |
36 // and has a size field. NOTE: FreeChunks are distinguished from allocated | |
37 // objects in two ways (by the sweeper). The second word (prev) has the | |
38 // LSB set to indicate a free chunk; allocated objects' klass() pointers | |
39 // don't have their LSB set. The corresponding bit in the CMSBitMap is | |
40 // set when the chunk is allocated. There are also blocks that "look free" | |
41 // but are not part of the free list and should not be coalesced into larger | |
42 // free blocks. These free blocks have their two LSB's set. | |
43 | |
44 class FreeChunk VALUE_OBJ_CLASS_SPEC { | |
45 friend class VMStructs; | |
46 FreeChunk* _next; | |
47 FreeChunk* _prev; | |
48 size_t _size; | |
49 | |
50 public: | |
51 NOT_PRODUCT(static const size_t header_size();) | |
52 // Returns "true" if the "wrd", which is required to be the second word | |
53 // of a block, indicates that the block represents a free chunk. | |
54 static bool secondWordIndicatesFreeChunk(intptr_t wrd) { | |
55 return (wrd & 0x1) == 0x1; | |
56 } | |
57 bool isFree() const { | |
58 return secondWordIndicatesFreeChunk((intptr_t)_prev); | |
59 } | |
60 bool cantCoalesce() const { return (((intptr_t)_prev) & 0x3) == 0x3; } | |
61 FreeChunk* next() const { return _next; } | |
62 FreeChunk* prev() const { return (FreeChunk*)(((intptr_t)_prev) & ~(0x3)); } | |
63 debug_only(void* prev_addr() const { return (void*)&_prev; }) | |
64 | |
65 void linkAfter(FreeChunk* ptr) { | |
66 linkNext(ptr); | |
67 if (ptr != NULL) ptr->linkPrev(this); | |
68 } | |
69 void linkAfterNonNull(FreeChunk* ptr) { | |
70 assert(ptr != NULL, "precondition violation"); | |
71 linkNext(ptr); | |
72 ptr->linkPrev(this); | |
73 } | |
74 void linkNext(FreeChunk* ptr) { _next = ptr; } | |
75 void linkPrev(FreeChunk* ptr) { _prev = (FreeChunk*)((intptr_t)ptr | 0x1); } | |
76 void clearPrev() { _prev = NULL; } | |
77 void clearNext() { _next = NULL; } | |
78 void dontCoalesce() { | |
79 // the block should be free | |
80 assert(isFree(), "Should look like a free block"); | |
81 _prev = (FreeChunk*)(((intptr_t)_prev) | 0x2); | |
82 } | |
83 void markFree() { _prev = (FreeChunk*)((intptr_t)_prev | 0x1); } | |
84 void markNotFree() { _prev = NULL; } | |
85 | |
86 size_t size() const { return _size; } | |
87 void setSize(size_t size) { _size = size; } | |
88 | |
89 // For volatile reads: | |
90 size_t* size_addr() { return &_size; } | |
91 | |
92 // Return the address past the end of this chunk | |
93 HeapWord* end() const { return ((HeapWord*) this) + _size; } | |
94 | |
95 // debugging | |
96 void verify() const PRODUCT_RETURN; | |
97 void verifyList() const PRODUCT_RETURN; | |
98 void mangleAllocated(size_t size) PRODUCT_RETURN; | |
99 void mangleFreed(size_t size) PRODUCT_RETURN; | |
100 }; | |
101 | |
102 // Alignment helpers etc. | |
103 #define numQuanta(x,y) ((x+y-1)/y) | |
104 enum AlignmentConstants { | |
105 MinChunkSize = numQuanta(sizeof(FreeChunk), MinObjAlignmentInBytes) * MinObjAlignment | |
106 }; | |
107 | |
108 // A FreeBlockDictionary is an abstract superclass that will allow | |
109 // a number of alternative implementations in the future. | |
110 class FreeBlockDictionary: public CHeapObj { | |
111 public: | |
112 enum Dither { | |
113 atLeast, | |
114 exactly, | |
115 roughly | |
116 }; | |
117 enum DictionaryChoice { | |
118 dictionaryBinaryTree = 0, | |
119 dictionarySplayTree = 1, | |
120 dictionarySkipList = 2 | |
121 }; | |
122 | |
123 private: | |
124 NOT_PRODUCT(Mutex* _lock;) | |
125 | |
126 public: | |
127 virtual void removeChunk(FreeChunk* fc) = 0; | |
128 virtual FreeChunk* getChunk(size_t size, Dither dither = atLeast) = 0; | |
129 virtual void returnChunk(FreeChunk* chunk) = 0; | |
130 virtual size_t totalChunkSize(debug_only(const Mutex* lock)) const = 0; | |
131 virtual size_t maxChunkSize() const = 0; | |
132 virtual size_t minSize() const = 0; | |
133 // Reset the dictionary to the initial conditions for a single | |
134 // block. | |
135 virtual void reset(HeapWord* addr, size_t size) = 0; | |
136 virtual void reset() = 0; | |
137 | |
138 virtual void dictCensusUpdate(size_t size, bool split, bool birth) = 0; | |
139 virtual bool coalDictOverPopulated(size_t size) = 0; | |
140 virtual void beginSweepDictCensus(double coalSurplusPercent, | |
141 float sweep_current, float sweep_ewstimate) = 0; | |
142 virtual void endSweepDictCensus(double splitSurplusPercent) = 0; | |
143 virtual FreeChunk* findLargestDict() const = 0; | |
144 // verify that the given chunk is in the dictionary. | |
145 virtual bool verifyChunkInFreeLists(FreeChunk* tc) const = 0; | |
146 | |
147 // Sigma_{all_free_blocks} (block_size^2) | |
148 virtual double sum_of_squared_block_sizes() const = 0; | |
149 | |
150 virtual FreeChunk* find_chunk_ends_at(HeapWord* target) const = 0; | |
151 virtual void inc_totalSize(size_t v) = 0; | |
152 virtual void dec_totalSize(size_t v) = 0; | |
153 | |
154 NOT_PRODUCT ( | |
155 virtual size_t sumDictReturnedBytes() = 0; | |
156 virtual void initializeDictReturnedBytes() = 0; | |
157 virtual size_t totalCount() = 0; | |
158 ) | |
159 | |
160 virtual void reportStatistics() const { | |
161 gclog_or_tty->print("No statistics available"); | |
162 } | |
163 | |
164 virtual void printDictCensus() const = 0; | |
165 | |
166 virtual void verify() const = 0; | |
167 | |
168 Mutex* par_lock() const PRODUCT_RETURN0; | |
169 void set_par_lock(Mutex* lock) PRODUCT_RETURN; | |
170 void verify_par_locked() const PRODUCT_RETURN; | |
171 }; |