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0
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1 /*
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2 * Copyright 1997-2006 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 # include "incls/_precompiled.incl"
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26 # include "incls/_heap.cpp.incl"
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27
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28
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29 size_t CodeHeap::header_size() {
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30 return sizeof(HeapBlock);
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31 }
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32
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33
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34 // Implementation of Heap
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35
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36 CodeHeap::CodeHeap() {
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37 _number_of_committed_segments = 0;
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38 _number_of_reserved_segments = 0;
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39 _segment_size = 0;
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40 _log2_segment_size = 0;
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41 _next_segment = 0;
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42 _freelist = NULL;
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43 _free_segments = 0;
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44 }
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45
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46
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47 void CodeHeap::mark_segmap_as_free(size_t beg, size_t end) {
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48 assert(0 <= beg && beg < _number_of_committed_segments, "interval begin out of bounds");
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49 assert(beg < end && end <= _number_of_committed_segments, "interval end out of bounds");
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50 // setup _segmap pointers for faster indexing
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51 address p = (address)_segmap.low() + beg;
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52 address q = (address)_segmap.low() + end;
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53 // initialize interval
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54 while (p < q) *p++ = 0xFF;
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55 }
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56
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57
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58 void CodeHeap::mark_segmap_as_used(size_t beg, size_t end) {
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59 assert(0 <= beg && beg < _number_of_committed_segments, "interval begin out of bounds");
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60 assert(beg < end && end <= _number_of_committed_segments, "interval end out of bounds");
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61 // setup _segmap pointers for faster indexing
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62 address p = (address)_segmap.low() + beg;
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63 address q = (address)_segmap.low() + end;
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64 // initialize interval
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65 int i = 0;
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66 while (p < q) {
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67 *p++ = i++;
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68 if (i == 0xFF) i = 1;
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69 }
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70 }
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71
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72
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73 static size_t align_to_page_size(size_t size) {
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74 const size_t alignment = (size_t)os::vm_page_size();
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75 assert(is_power_of_2(alignment), "no kidding ???");
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76 return (size + alignment - 1) & ~(alignment - 1);
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77 }
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78
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79
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80 static size_t align_to_allocation_size(size_t size) {
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81 const size_t alignment = (size_t)os::vm_allocation_granularity();
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82 assert(is_power_of_2(alignment), "no kidding ???");
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83 return (size + alignment - 1) & ~(alignment - 1);
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84 }
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85
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86
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87 void CodeHeap::on_code_mapping(char* base, size_t size) {
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88 #ifdef LINUX
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89 extern void linux_wrap_code(char* base, size_t size);
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90 linux_wrap_code(base, size);
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91 #endif
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92 }
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93
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94
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95 bool CodeHeap::reserve(size_t reserved_size, size_t committed_size,
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96 size_t segment_size) {
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97 assert(reserved_size >= committed_size, "reserved < committed");
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98 assert(segment_size >= sizeof(FreeBlock), "segment size is too small");
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99 assert(is_power_of_2(segment_size), "segment_size must be a power of 2");
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100
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101 _segment_size = segment_size;
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102 _log2_segment_size = exact_log2(segment_size);
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103
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104 // Reserve and initialize space for _memory.
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105 const size_t page_size = os::page_size_for_region(committed_size,
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106 reserved_size, 8);
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107 const size_t granularity = os::vm_allocation_granularity();
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108 const size_t r_align = MAX2(page_size, granularity);
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109 const size_t r_size = align_size_up(reserved_size, r_align);
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110 const size_t c_size = align_size_up(committed_size, page_size);
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111
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112 const size_t rs_align = page_size == (size_t) os::vm_page_size() ? 0 :
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113 MAX2(page_size, granularity);
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114 ReservedSpace rs(r_size, rs_align, false);
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115 os::trace_page_sizes("code heap", committed_size, reserved_size, page_size,
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116 rs.base(), rs.size());
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117 if (!_memory.initialize(rs, c_size)) {
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118 return false;
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119 }
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120
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121 on_code_mapping(_memory.low(), _memory.committed_size());
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122 _number_of_committed_segments = number_of_segments(_memory.committed_size());
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123 _number_of_reserved_segments = number_of_segments(_memory.reserved_size());
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124 assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking");
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125
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126 // reserve space for _segmap
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127 if (!_segmap.initialize(align_to_page_size(_number_of_reserved_segments), align_to_page_size(_number_of_committed_segments))) {
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128 return false;
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129 }
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130 assert(_segmap.committed_size() >= (size_t) _number_of_committed_segments, "could not commit enough space for segment map");
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131 assert(_segmap.reserved_size() >= (size_t) _number_of_reserved_segments , "could not reserve enough space for segment map");
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132 assert(_segmap.reserved_size() >= _segmap.committed_size() , "just checking");
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133
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134 // initialize remaining instance variables
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135 clear();
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136 return true;
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137 }
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138
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139
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140 void CodeHeap::release() {
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141 Unimplemented();
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142 }
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143
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144
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145 bool CodeHeap::expand_by(size_t size) {
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146 // expand _memory space
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147 size_t dm = align_to_page_size(_memory.committed_size() + size) - _memory.committed_size();
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148 if (dm > 0) {
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149 char* base = _memory.low() + _memory.committed_size();
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150 if (!_memory.expand_by(dm)) return false;
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151 on_code_mapping(base, dm);
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152 size_t i = _number_of_committed_segments;
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153 _number_of_committed_segments = number_of_segments(_memory.committed_size());
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154 assert(_number_of_reserved_segments == number_of_segments(_memory.reserved_size()), "number of reserved segments should not change");
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155 assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking");
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156 // expand _segmap space
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157 size_t ds = align_to_page_size(_number_of_committed_segments) - _segmap.committed_size();
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158 if (ds > 0) {
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159 if (!_segmap.expand_by(ds)) return false;
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160 }
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161 assert(_segmap.committed_size() >= (size_t) _number_of_committed_segments, "just checking");
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162 // initialize additional segmap entries
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163 mark_segmap_as_free(i, _number_of_committed_segments);
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164 }
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165 return true;
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166 }
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167
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168
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169 void CodeHeap::shrink_by(size_t size) {
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170 Unimplemented();
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171 }
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172
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173
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174 void CodeHeap::clear() {
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175 _next_segment = 0;
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176 mark_segmap_as_free(0, _number_of_committed_segments);
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177 }
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178
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179
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180 void* CodeHeap::allocate(size_t size) {
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181 size_t length = number_of_segments(size + sizeof(HeapBlock));
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182 assert(length *_segment_size >= sizeof(FreeBlock), "not enough room for FreeList");
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183
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184 // First check if we can satify request from freelist
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185 debug_only(verify());
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186 HeapBlock* block = search_freelist(length);
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187 debug_only(if (VerifyCodeCacheOften) verify());
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188 if (block != NULL) {
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189 assert(block->length() >= length && block->length() < length + CodeCacheMinBlockLength, "sanity check");
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190 assert(!block->free(), "must be marked free");
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191 #ifdef ASSERT
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192 memset((void *)block->allocated_space(), badCodeHeapNewVal, size);
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193 #endif
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194 return block->allocated_space();
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195 }
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196
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197 if (length < CodeCacheMinBlockLength) {
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198 length = CodeCacheMinBlockLength;
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199 }
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200 if (_next_segment + length <= _number_of_committed_segments) {
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201 mark_segmap_as_used(_next_segment, _next_segment + length);
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202 HeapBlock* b = block_at(_next_segment);
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203 b->initialize(length);
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204 _next_segment += length;
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205 #ifdef ASSERT
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206 memset((void *)b->allocated_space(), badCodeHeapNewVal, size);
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207 #endif
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208 return b->allocated_space();
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209 } else {
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210 return NULL;
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211 }
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212 }
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213
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214
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215 void CodeHeap::deallocate(void* p) {
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216 assert(p == find_start(p), "illegal deallocation");
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217 // Find start of HeapBlock
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218 HeapBlock* b = (((HeapBlock *)p) - 1);
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219 assert(b->allocated_space() == p, "sanity check");
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220 #ifdef ASSERT
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221 memset((void *)b->allocated_space(),
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222 badCodeHeapFreeVal,
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223 size(b->length()) - sizeof(HeapBlock));
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224 #endif
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225 add_to_freelist(b);
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226
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227 debug_only(if (VerifyCodeCacheOften) verify());
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228 }
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229
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230
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231 void* CodeHeap::find_start(void* p) const {
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232 if (!contains(p)) {
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233 return NULL;
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234 }
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235 size_t i = segment_for(p);
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236 address b = (address)_segmap.low();
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237 if (b[i] == 0xFF) {
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238 return NULL;
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239 }
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240 while (b[i] > 0) i -= (int)b[i];
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241 HeapBlock* h = block_at(i);
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242 if (h->free()) {
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243 return NULL;
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244 }
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245 return h->allocated_space();
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246 }
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247
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248
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249 size_t CodeHeap::alignment_unit() const {
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250 // this will be a power of two
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251 return _segment_size;
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252 }
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253
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254
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255 size_t CodeHeap::alignment_offset() const {
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256 // The lowest address in any allocated block will be
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257 // equal to alignment_offset (mod alignment_unit).
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258 return sizeof(HeapBlock) & (_segment_size - 1);
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259 }
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260
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261 // Finds the next free heapblock. If the current one is free, that it returned
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262 void* CodeHeap::next_free(HeapBlock *b) const {
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263 // Since free blocks are merged, there is max. on free block
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264 // between two used ones
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265 if (b != NULL && b->free()) b = next_block(b);
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266 assert(b == NULL || !b->free(), "must be in use or at end of heap");
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267 return (b == NULL) ? NULL : b->allocated_space();
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268 }
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269
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270 // Returns the first used HeapBlock
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271 HeapBlock* CodeHeap::first_block() const {
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272 if (_next_segment > 0)
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273 return block_at(0);
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274 return NULL;
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275 }
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276
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277 HeapBlock *CodeHeap::block_start(void *q) const {
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278 HeapBlock* b = (HeapBlock*)find_start(q);
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279 if (b == NULL) return NULL;
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280 return b - 1;
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281 }
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282
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283 // Returns the next Heap block an offset into one
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284 HeapBlock* CodeHeap::next_block(HeapBlock *b) const {
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285 if (b == NULL) return NULL;
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286 size_t i = segment_for(b) + b->length();
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287 if (i < _next_segment)
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288 return block_at(i);
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289 return NULL;
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290 }
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291
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292
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293 // Returns current capacity
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294 size_t CodeHeap::capacity() const {
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295 return _memory.committed_size();
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296 }
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297
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298 size_t CodeHeap::max_capacity() const {
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299 return _memory.reserved_size();
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300 }
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301
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302 size_t CodeHeap::allocated_capacity() const {
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303 // Start with the committed size in _memory;
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304 size_t l = _memory.committed_size();
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305
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306 // Subtract the committed, but unused, segments
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307 l -= size(_number_of_committed_segments - _next_segment);
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308
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309 // Subtract the size of the freelist
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310 l -= size(_free_segments);
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311
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312 return l;
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313 }
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314
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315 // Free list management
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316
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317 FreeBlock *CodeHeap::following_block(FreeBlock *b) {
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318 return (FreeBlock*)(((address)b) + _segment_size * b->length());
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319 }
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320
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321 // Inserts block b after a
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322 void CodeHeap::insert_after(FreeBlock* a, FreeBlock* b) {
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323 assert(a != NULL && b != NULL, "must be real pointers");
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324
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325 // Link b into the list after a
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326 b->set_link(a->link());
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327 a->set_link(b);
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328
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329 // See if we can merge blocks
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330 merge_right(b); // Try to make b bigger
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331 merge_right(a); // Try to make a include b
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332 }
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333
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334 // Try to merge this block with the following block
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335 void CodeHeap::merge_right(FreeBlock *a) {
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336 assert(a->free(), "must be a free block");
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337 if (following_block(a) == a->link()) {
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338 assert(a->link() != NULL && a->link()->free(), "must be free too");
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339 // Update block a to include the following block
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340 a->set_length(a->length() + a->link()->length());
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341 a->set_link(a->link()->link());
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342 // Update find_start map
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343 size_t beg = segment_for(a);
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344 mark_segmap_as_used(beg, beg + a->length());
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345 }
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346 }
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347
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348 void CodeHeap::add_to_freelist(HeapBlock *a) {
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349 FreeBlock* b = (FreeBlock*)a;
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350 assert(b != _freelist, "cannot be removed twice");
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351
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352 // Mark as free and update free space count
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353 _free_segments += b->length();
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354 b->set_free();
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355
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356 // First element in list?
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357 if (_freelist == NULL) {
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358 _freelist = b;
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359 b->set_link(NULL);
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360 return;
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361 }
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362
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363 // Scan for right place to put into list. List
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364 // is sorted by increasing addresseses
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365 FreeBlock* prev = NULL;
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366 FreeBlock* cur = _freelist;
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367 while(cur != NULL && cur < b) {
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368 assert(prev == NULL || prev < cur, "must be ordered");
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369 prev = cur;
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370 cur = cur->link();
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371 }
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372
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373 assert( (prev == NULL && b < _freelist) ||
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374 (prev < b && (cur == NULL || b < cur)), "list must be ordered");
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375
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376 if (prev == NULL) {
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377 // Insert first in list
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378 b->set_link(_freelist);
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379 _freelist = b;
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380 merge_right(_freelist);
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381 } else {
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382 insert_after(prev, b);
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383 }
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384 }
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385
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386 // Search freelist for an entry on the list with the best fit
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387 // Return NULL if no one was found
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388 FreeBlock* CodeHeap::search_freelist(size_t length) {
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389 FreeBlock *best_block = NULL;
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390 FreeBlock *best_prev = NULL;
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391 size_t best_length = 0;
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392
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393 // Search for smallest block which is bigger than length
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394 FreeBlock *prev = NULL;
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395 FreeBlock *cur = _freelist;
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396 while(cur != NULL) {
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397 size_t l = cur->length();
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398 if (l >= length && (best_block == NULL || best_length > l)) {
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|
|
399 // Remember best block, its previous element, and its length
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400 best_block = cur;
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401 best_prev = prev;
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402 best_length = best_block->length();
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403 }
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404
|
|
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405 // Next element in list
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406 prev = cur;
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407 cur = cur->link();
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408 }
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409
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410 if (best_block == NULL) {
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|
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411 // None found
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412 return NULL;
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|
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413 }
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|
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414
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|
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415 assert((best_prev == NULL && _freelist == best_block ) ||
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416 (best_prev != NULL && best_prev->link() == best_block), "sanity check");
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417
|
|
|
418 // Exact (or at least good enough) fit. Remove from list.
|
|
|
419 // Don't leave anything on the freelist smaller than CodeCacheMinBlockLength.
|
|
|
420 if (best_length < length + CodeCacheMinBlockLength) {
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|
|
421 length = best_length;
|
|
|
422 if (best_prev == NULL) {
|
|
|
423 assert(_freelist == best_block, "sanity check");
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|
|
424 _freelist = _freelist->link();
|
|
|
425 } else {
|
|
|
426 // Unmap element
|
|
|
427 best_prev->set_link(best_block->link());
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|
|
428 }
|
|
|
429 } else {
|
|
|
430 // Truncate block and return a pointer to the following block
|
|
|
431 best_block->set_length(best_length - length);
|
|
|
432 best_block = following_block(best_block);
|
|
|
433 // Set used bit and length on new block
|
|
|
434 size_t beg = segment_for(best_block);
|
|
|
435 mark_segmap_as_used(beg, beg + length);
|
|
|
436 best_block->set_length(length);
|
|
|
437 }
|
|
|
438
|
|
|
439 best_block->set_used();
|
|
|
440 _free_segments -= length;
|
|
|
441 return best_block;
|
|
|
442 }
|
|
|
443
|
|
|
444 //----------------------------------------------------------------------------
|
|
|
445 // Non-product code
|
|
|
446
|
|
|
447 #ifndef PRODUCT
|
|
|
448
|
|
|
449 void CodeHeap::print() {
|
|
|
450 tty->print_cr("The Heap");
|
|
|
451 }
|
|
|
452
|
|
|
453 #endif
|
|
|
454
|
|
|
455 void CodeHeap::verify() {
|
|
|
456 // Count the number of blocks on the freelist, and the amount of space
|
|
|
457 // represented.
|
|
|
458 int count = 0;
|
|
|
459 size_t len = 0;
|
|
|
460 for(FreeBlock* b = _freelist; b != NULL; b = b->link()) {
|
|
|
461 len += b->length();
|
|
|
462 count++;
|
|
|
463 }
|
|
|
464
|
|
|
465 // Verify that freelist contains the right amount of free space
|
|
|
466 guarantee(len == _free_segments, "wrong freelist");
|
|
|
467
|
|
|
468 // Verify that the number of free blocks is not out of hand.
|
|
|
469 static int free_block_threshold = 10000;
|
|
|
470 if (count > free_block_threshold) {
|
|
|
471 warning("CodeHeap: # of free blocks > %d", free_block_threshold);
|
|
|
472 // Double the warning limit
|
|
|
473 free_block_threshold *= 2;
|
|
|
474 }
|
|
|
475
|
|
|
476 // Verify that the freelist contains the same number of free blocks that is
|
|
|
477 // found on the full list.
|
|
|
478 for(HeapBlock *h = first_block(); h != NULL; h = next_block(h)) {
|
|
|
479 if (h->free()) count--;
|
|
|
480 }
|
|
|
481 guarantee(count == 0, "missing free blocks");
|
|
|
482 }
|
