Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/g1/heapRegionSeq.hpp @ 4727:67fdcb391461
7119027: G1: use atomics to update RS length / predict time of inc CSet
Summary: Make sure that the updates to the RS length and inc CSet predicted time are updated in an MT-safe way.
Reviewed-by: brutisso, iveresov
author | tonyp |
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date | Wed, 21 Dec 2011 07:53:53 -0500 |
parents | 4f93f0d00802 |
children | 720b6a76dd9d |
rev | line source |
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342 | 1 /* |
2149 | 2 * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved. |
342 | 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 | |
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12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
342 | 22 * |
23 */ | |
24 | |
1972 | 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP |
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP | |
27 | |
342 | 28 class HeapRegion; |
29 class HeapRegionClosure; | |
3766 | 30 class FreeRegionList; |
31 | |
32 #define G1_NULL_HRS_INDEX ((size_t) -1) | |
33 | |
34 // This class keeps track of the region metadata (i.e., HeapRegion | |
35 // instances). They are kept in the _regions array in address | |
36 // order. A region's index in the array corresponds to its index in | |
37 // the heap (i.e., 0 is the region at the bottom of the heap, 1 is | |
38 // the one after it, etc.). Two regions that are consecutive in the | |
39 // array should also be adjacent in the address space (i.e., | |
40 // region(i).end() == region(i+1).bottom(). | |
41 // | |
42 // We create a HeapRegion when we commit the region's address space | |
43 // for the first time. When we uncommit the address space of a | |
44 // region we retain the HeapRegion to be able to re-use it in the | |
45 // future (in case we recommit it). | |
46 // | |
47 // We keep track of three lengths: | |
48 // | |
49 // * _length (returned by length()) is the number of currently | |
50 // committed regions. | |
51 // * _allocated_length (not exposed outside this class) is the | |
52 // number of regions for which we have HeapRegions. | |
53 // * _max_length (returned by max_length()) is the maximum number of | |
54 // regions the heap can have. | |
55 // | |
56 // and maintain that: _length <= _allocated_length <= _max_length | |
342 | 57 |
58 class HeapRegionSeq: public CHeapObj { | |
3972 | 59 friend class VMStructs; |
342 | 60 |
3766 | 61 // The array that holds the HeapRegions. |
62 HeapRegion** _regions; | |
63 | |
64 // Version of _regions biased to address 0 | |
65 HeapRegion** _regions_biased; | |
66 | |
67 // The number of regions committed in the heap. | |
68 size_t _length; | |
342 | 69 |
3766 | 70 // The address of the first reserved word in the heap. |
71 HeapWord* _heap_bottom; | |
72 | |
73 // The address of the last reserved word in the heap - 1. | |
74 HeapWord* _heap_end; | |
75 | |
76 // The log of the region byte size. | |
77 size_t _region_shift; | |
78 | |
79 // A hint for which index to start searching from for humongous | |
80 // allocations. | |
81 size_t _next_search_index; | |
342 | 82 |
3766 | 83 // The number of regions for which we have allocated HeapRegions for. |
84 size_t _allocated_length; | |
85 | |
86 // The maximum number of regions in the heap. | |
87 size_t _max_length; | |
88 | |
89 // Find a contiguous set of empty regions of length num, starting | |
90 // from the given index. | |
91 size_t find_contiguous_from(size_t from, size_t num); | |
342 | 92 |
3766 | 93 // Map a heap address to a biased region index. Assume that the |
94 // address is valid. | |
95 inline size_t addr_to_index_biased(HeapWord* addr) const; | |
342 | 96 |
3766 | 97 void increment_length(size_t* length) { |
98 assert(*length < _max_length, "pre-condition"); | |
99 *length += 1; | |
100 } | |
101 | |
102 void decrement_length(size_t* length) { | |
103 assert(*length > 0, "pre-condition"); | |
104 *length -= 1; | |
105 } | |
342 | 106 |
107 public: | |
3766 | 108 // Empty contructor, we'll initialize it with the initialize() method. |
109 HeapRegionSeq() { } | |
110 | |
111 void initialize(HeapWord* bottom, HeapWord* end, size_t max_length); | |
342 | 112 |
3766 | 113 // Return the HeapRegion at the given index. Assume that the index |
114 // is valid. | |
115 inline HeapRegion* at(size_t index) const; | |
116 | |
117 // If addr is within the committed space return its corresponding | |
118 // HeapRegion, otherwise return NULL. | |
119 inline HeapRegion* addr_to_region(HeapWord* addr) const; | |
120 | |
121 // Return the HeapRegion that corresponds to the given | |
122 // address. Assume the address is valid. | |
123 inline HeapRegion* addr_to_region_unsafe(HeapWord* addr) const; | |
342 | 124 |
3766 | 125 // Return the number of regions that have been committed in the heap. |
126 size_t length() const { return _length; } | |
127 | |
128 // Return the maximum number of regions in the heap. | |
129 size_t max_length() const { return _max_length; } | |
342 | 130 |
3766 | 131 // Expand the sequence to reflect that the heap has grown from |
132 // old_end to new_end. Either create new HeapRegions, or re-use | |
133 // existing ones, and return them in the given list. Returns the | |
134 // memory region that covers the newly-created regions. If a | |
135 // HeapRegion allocation fails, the result memory region might be | |
136 // smaller than the desired one. | |
137 MemRegion expand_by(HeapWord* old_end, HeapWord* new_end, | |
138 FreeRegionList* list); | |
342 | 139 |
3766 | 140 // Return the number of contiguous regions at the end of the sequence |
342 | 141 // that are available for allocation. |
142 size_t free_suffix(); | |
143 | |
2361 | 144 // Find a contiguous set of empty regions of length num and return |
3766 | 145 // the index of the first region or G1_NULL_HRS_INDEX if the |
146 // search was unsuccessful. | |
147 size_t find_contiguous(size_t num); | |
342 | 148 |
3766 | 149 // Apply blk->doHeapRegion() on all committed regions in address order, |
150 // terminating the iteration early if doHeapRegion() returns true. | |
151 void iterate(HeapRegionClosure* blk) const; | |
342 | 152 |
3766 | 153 // As above, but start the iteration from hr and loop around. If hr |
154 // is NULL, we start from the first region in the heap. | |
155 void iterate_from(HeapRegion* hr, HeapRegionClosure* blk) const; | |
342 | 156 |
3766 | 157 // Tag as uncommitted as many regions that are completely free as |
158 // possible, up to shrink_bytes, from the suffix of the committed | |
159 // sequence. Return a MemRegion that corresponds to the address | |
160 // range of the uncommitted regions. Assume shrink_bytes is page and | |
161 // heap region aligned. | |
162 MemRegion shrink_by(size_t shrink_bytes, size_t* num_regions_deleted); | |
342 | 163 |
3766 | 164 // Do some sanity checking. |
165 void verify_optional() PRODUCT_RETURN; | |
342 | 166 }; |
1972 | 167 |
168 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP |