Tue, 17 Oct 2017 12:58:25 +0800
merge
aoqi@0 | 1 | /* |
aoqi@0 | 2 | * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. |
aoqi@0 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
aoqi@0 | 4 | * |
aoqi@0 | 5 | * This code is free software; you can redistribute it and/or modify it |
aoqi@0 | 6 | * under the terms of the GNU General Public License version 2 only, as |
aoqi@0 | 7 | * published by the Free Software Foundation. |
aoqi@0 | 8 | * |
aoqi@0 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
aoqi@0 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
aoqi@0 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
aoqi@0 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
aoqi@0 | 13 | * accompanied this code). |
aoqi@0 | 14 | * |
aoqi@0 | 15 | * You should have received a copy of the GNU General Public License version |
aoqi@0 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
aoqi@0 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
aoqi@0 | 18 | * |
aoqi@0 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
aoqi@0 | 20 | * or visit www.oracle.com if you need additional information or have any |
aoqi@0 | 21 | * questions. |
aoqi@0 | 22 | * |
aoqi@0 | 23 | */ |
aoqi@0 | 24 | |
aoqi@0 | 25 | #include "precompiled.hpp" |
aoqi@0 | 26 | #include "memory/heap.hpp" |
aoqi@0 | 27 | #include "oops/oop.inline.hpp" |
aoqi@0 | 28 | #include "runtime/os.hpp" |
aoqi@0 | 29 | #include "services/memTracker.hpp" |
aoqi@0 | 30 | |
aoqi@0 | 31 | size_t CodeHeap::header_size() { |
aoqi@0 | 32 | return sizeof(HeapBlock); |
aoqi@0 | 33 | } |
aoqi@0 | 34 | |
aoqi@0 | 35 | |
aoqi@0 | 36 | // Implementation of Heap |
aoqi@0 | 37 | |
aoqi@0 | 38 | CodeHeap::CodeHeap() { |
aoqi@0 | 39 | _number_of_committed_segments = 0; |
aoqi@0 | 40 | _number_of_reserved_segments = 0; |
aoqi@0 | 41 | _segment_size = 0; |
aoqi@0 | 42 | _log2_segment_size = 0; |
aoqi@0 | 43 | _next_segment = 0; |
aoqi@0 | 44 | _freelist = NULL; |
aoqi@0 | 45 | _freelist_segments = 0; |
aoqi@0 | 46 | } |
aoqi@0 | 47 | |
aoqi@0 | 48 | |
aoqi@0 | 49 | void CodeHeap::mark_segmap_as_free(size_t beg, size_t end) { |
aoqi@0 | 50 | assert(0 <= beg && beg < _number_of_committed_segments, "interval begin out of bounds"); |
aoqi@0 | 51 | assert(beg < end && end <= _number_of_committed_segments, "interval end out of bounds"); |
aoqi@0 | 52 | // setup _segmap pointers for faster indexing |
aoqi@0 | 53 | address p = (address)_segmap.low() + beg; |
aoqi@0 | 54 | address q = (address)_segmap.low() + end; |
aoqi@0 | 55 | // initialize interval |
aoqi@0 | 56 | while (p < q) *p++ = 0xFF; |
aoqi@0 | 57 | } |
aoqi@0 | 58 | |
aoqi@0 | 59 | |
aoqi@0 | 60 | void CodeHeap::mark_segmap_as_used(size_t beg, size_t end) { |
aoqi@0 | 61 | assert(0 <= beg && beg < _number_of_committed_segments, "interval begin out of bounds"); |
aoqi@0 | 62 | assert(beg < end && end <= _number_of_committed_segments, "interval end out of bounds"); |
aoqi@0 | 63 | // setup _segmap pointers for faster indexing |
aoqi@0 | 64 | address p = (address)_segmap.low() + beg; |
aoqi@0 | 65 | address q = (address)_segmap.low() + end; |
aoqi@0 | 66 | // initialize interval |
aoqi@0 | 67 | int i = 0; |
aoqi@0 | 68 | while (p < q) { |
aoqi@0 | 69 | *p++ = i++; |
aoqi@0 | 70 | if (i == 0xFF) i = 1; |
aoqi@0 | 71 | } |
aoqi@0 | 72 | } |
aoqi@0 | 73 | |
aoqi@0 | 74 | |
aoqi@0 | 75 | static size_t align_to_page_size(size_t size) { |
aoqi@0 | 76 | const size_t alignment = (size_t)os::vm_page_size(); |
aoqi@0 | 77 | assert(is_power_of_2(alignment), "no kidding ???"); |
aoqi@0 | 78 | return (size + alignment - 1) & ~(alignment - 1); |
aoqi@0 | 79 | } |
aoqi@0 | 80 | |
aoqi@0 | 81 | |
aoqi@0 | 82 | void CodeHeap::on_code_mapping(char* base, size_t size) { |
aoqi@0 | 83 | #ifdef LINUX |
aoqi@0 | 84 | extern void linux_wrap_code(char* base, size_t size); |
aoqi@0 | 85 | linux_wrap_code(base, size); |
aoqi@0 | 86 | #endif |
aoqi@0 | 87 | } |
aoqi@0 | 88 | |
aoqi@0 | 89 | |
aoqi@0 | 90 | bool CodeHeap::reserve(size_t reserved_size, size_t committed_size, |
aoqi@0 | 91 | size_t segment_size) { |
aoqi@0 | 92 | assert(reserved_size >= committed_size, "reserved < committed"); |
aoqi@0 | 93 | assert(segment_size >= sizeof(FreeBlock), "segment size is too small"); |
aoqi@0 | 94 | assert(is_power_of_2(segment_size), "segment_size must be a power of 2"); |
aoqi@0 | 95 | |
aoqi@0 | 96 | _segment_size = segment_size; |
aoqi@0 | 97 | _log2_segment_size = exact_log2(segment_size); |
aoqi@0 | 98 | |
aoqi@0 | 99 | // Reserve and initialize space for _memory. |
ehelin@7778 | 100 | size_t page_size = os::vm_page_size(); |
ehelin@7778 | 101 | if (os::can_execute_large_page_memory()) { |
ehelin@7880 | 102 | page_size = os::page_size_for_region_unaligned(reserved_size, 8); |
ehelin@7778 | 103 | } |
ehelin@7778 | 104 | |
aoqi@0 | 105 | const size_t granularity = os::vm_allocation_granularity(); |
aoqi@0 | 106 | const size_t r_align = MAX2(page_size, granularity); |
aoqi@0 | 107 | const size_t r_size = align_size_up(reserved_size, r_align); |
aoqi@0 | 108 | const size_t c_size = align_size_up(committed_size, page_size); |
aoqi@0 | 109 | |
aoqi@0 | 110 | const size_t rs_align = page_size == (size_t) os::vm_page_size() ? 0 : |
aoqi@0 | 111 | MAX2(page_size, granularity); |
aoqi@0 | 112 | ReservedCodeSpace rs(r_size, rs_align, rs_align > 0); |
aoqi@0 | 113 | os::trace_page_sizes("code heap", committed_size, reserved_size, page_size, |
aoqi@0 | 114 | rs.base(), rs.size()); |
aoqi@0 | 115 | if (!_memory.initialize(rs, c_size)) { |
aoqi@0 | 116 | return false; |
aoqi@0 | 117 | } |
aoqi@0 | 118 | |
aoqi@0 | 119 | on_code_mapping(_memory.low(), _memory.committed_size()); |
aoqi@0 | 120 | _number_of_committed_segments = size_to_segments(_memory.committed_size()); |
aoqi@0 | 121 | _number_of_reserved_segments = size_to_segments(_memory.reserved_size()); |
aoqi@0 | 122 | assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking"); |
aoqi@0 | 123 | const size_t reserved_segments_alignment = MAX2((size_t)os::vm_page_size(), granularity); |
aoqi@0 | 124 | const size_t reserved_segments_size = align_size_up(_number_of_reserved_segments, reserved_segments_alignment); |
aoqi@0 | 125 | const size_t committed_segments_size = align_to_page_size(_number_of_committed_segments); |
aoqi@0 | 126 | |
aoqi@0 | 127 | // reserve space for _segmap |
aoqi@0 | 128 | if (!_segmap.initialize(reserved_segments_size, committed_segments_size)) { |
aoqi@0 | 129 | return false; |
aoqi@0 | 130 | } |
aoqi@0 | 131 | |
aoqi@0 | 132 | MemTracker::record_virtual_memory_type((address)_segmap.low_boundary(), mtCode); |
aoqi@0 | 133 | |
aoqi@0 | 134 | assert(_segmap.committed_size() >= (size_t) _number_of_committed_segments, "could not commit enough space for segment map"); |
aoqi@0 | 135 | assert(_segmap.reserved_size() >= (size_t) _number_of_reserved_segments , "could not reserve enough space for segment map"); |
aoqi@0 | 136 | assert(_segmap.reserved_size() >= _segmap.committed_size() , "just checking"); |
aoqi@0 | 137 | |
aoqi@0 | 138 | // initialize remaining instance variables |
aoqi@0 | 139 | clear(); |
aoqi@0 | 140 | return true; |
aoqi@0 | 141 | } |
aoqi@0 | 142 | |
aoqi@0 | 143 | |
aoqi@0 | 144 | void CodeHeap::release() { |
aoqi@0 | 145 | Unimplemented(); |
aoqi@0 | 146 | } |
aoqi@0 | 147 | |
aoqi@0 | 148 | |
aoqi@0 | 149 | bool CodeHeap::expand_by(size_t size) { |
aoqi@0 | 150 | // expand _memory space |
aoqi@0 | 151 | size_t dm = align_to_page_size(_memory.committed_size() + size) - _memory.committed_size(); |
aoqi@0 | 152 | if (dm > 0) { |
aoqi@0 | 153 | char* base = _memory.low() + _memory.committed_size(); |
aoqi@0 | 154 | if (!_memory.expand_by(dm)) return false; |
aoqi@0 | 155 | on_code_mapping(base, dm); |
aoqi@0 | 156 | size_t i = _number_of_committed_segments; |
aoqi@0 | 157 | _number_of_committed_segments = size_to_segments(_memory.committed_size()); |
aoqi@0 | 158 | assert(_number_of_reserved_segments == size_to_segments(_memory.reserved_size()), "number of reserved segments should not change"); |
aoqi@0 | 159 | assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking"); |
aoqi@0 | 160 | // expand _segmap space |
aoqi@0 | 161 | size_t ds = align_to_page_size(_number_of_committed_segments) - _segmap.committed_size(); |
aoqi@0 | 162 | if (ds > 0) { |
aoqi@0 | 163 | if (!_segmap.expand_by(ds)) return false; |
aoqi@0 | 164 | } |
aoqi@0 | 165 | assert(_segmap.committed_size() >= (size_t) _number_of_committed_segments, "just checking"); |
aoqi@0 | 166 | // initialize additional segmap entries |
aoqi@0 | 167 | mark_segmap_as_free(i, _number_of_committed_segments); |
aoqi@0 | 168 | } |
aoqi@0 | 169 | return true; |
aoqi@0 | 170 | } |
aoqi@0 | 171 | |
aoqi@0 | 172 | |
aoqi@0 | 173 | void CodeHeap::shrink_by(size_t size) { |
aoqi@0 | 174 | Unimplemented(); |
aoqi@0 | 175 | } |
aoqi@0 | 176 | |
aoqi@0 | 177 | |
aoqi@0 | 178 | void CodeHeap::clear() { |
aoqi@0 | 179 | _next_segment = 0; |
aoqi@0 | 180 | mark_segmap_as_free(0, _number_of_committed_segments); |
aoqi@0 | 181 | } |
aoqi@0 | 182 | |
aoqi@0 | 183 | |
aoqi@0 | 184 | void* CodeHeap::allocate(size_t instance_size, bool is_critical) { |
aoqi@0 | 185 | size_t number_of_segments = size_to_segments(instance_size + sizeof(HeapBlock)); |
aoqi@0 | 186 | assert(segments_to_size(number_of_segments) >= sizeof(FreeBlock), "not enough room for FreeList"); |
aoqi@0 | 187 | |
aoqi@0 | 188 | // First check if we can satify request from freelist |
aoqi@0 | 189 | debug_only(verify()); |
aoqi@0 | 190 | HeapBlock* block = search_freelist(number_of_segments, is_critical); |
aoqi@0 | 191 | debug_only(if (VerifyCodeCacheOften) verify()); |
aoqi@0 | 192 | if (block != NULL) { |
aoqi@0 | 193 | assert(block->length() >= number_of_segments && block->length() < number_of_segments + CodeCacheMinBlockLength, "sanity check"); |
aoqi@0 | 194 | assert(!block->free(), "must be marked free"); |
aoqi@0 | 195 | #ifdef ASSERT |
aoqi@0 | 196 | memset((void *)block->allocated_space(), badCodeHeapNewVal, instance_size); |
aoqi@0 | 197 | #endif |
aoqi@0 | 198 | return block->allocated_space(); |
aoqi@0 | 199 | } |
aoqi@0 | 200 | |
aoqi@0 | 201 | // Ensure minimum size for allocation to the heap. |
aoqi@0 | 202 | if (number_of_segments < CodeCacheMinBlockLength) { |
aoqi@0 | 203 | number_of_segments = CodeCacheMinBlockLength; |
aoqi@0 | 204 | } |
aoqi@0 | 205 | |
aoqi@0 | 206 | if (!is_critical) { |
aoqi@0 | 207 | // Make sure the allocation fits in the unallocated heap without using |
aoqi@0 | 208 | // the CodeCacheMimimumFreeSpace that is reserved for critical allocations. |
aoqi@0 | 209 | if (segments_to_size(number_of_segments) > (heap_unallocated_capacity() - CodeCacheMinimumFreeSpace)) { |
aoqi@0 | 210 | // Fail allocation |
aoqi@0 | 211 | return NULL; |
aoqi@0 | 212 | } |
aoqi@0 | 213 | } |
aoqi@0 | 214 | |
aoqi@0 | 215 | if (_next_segment + number_of_segments <= _number_of_committed_segments) { |
aoqi@0 | 216 | mark_segmap_as_used(_next_segment, _next_segment + number_of_segments); |
aoqi@0 | 217 | HeapBlock* b = block_at(_next_segment); |
aoqi@0 | 218 | b->initialize(number_of_segments); |
aoqi@0 | 219 | _next_segment += number_of_segments; |
aoqi@0 | 220 | #ifdef ASSERT |
aoqi@0 | 221 | memset((void *)b->allocated_space(), badCodeHeapNewVal, instance_size); |
aoqi@0 | 222 | #endif |
aoqi@0 | 223 | return b->allocated_space(); |
aoqi@0 | 224 | } else { |
aoqi@0 | 225 | return NULL; |
aoqi@0 | 226 | } |
aoqi@0 | 227 | } |
aoqi@0 | 228 | |
aoqi@0 | 229 | |
aoqi@0 | 230 | void CodeHeap::deallocate(void* p) { |
aoqi@0 | 231 | assert(p == find_start(p), "illegal deallocation"); |
aoqi@0 | 232 | // Find start of HeapBlock |
aoqi@0 | 233 | HeapBlock* b = (((HeapBlock *)p) - 1); |
aoqi@0 | 234 | assert(b->allocated_space() == p, "sanity check"); |
aoqi@0 | 235 | #ifdef ASSERT |
aoqi@0 | 236 | memset((void *)b->allocated_space(), |
aoqi@0 | 237 | badCodeHeapFreeVal, |
aoqi@0 | 238 | segments_to_size(b->length()) - sizeof(HeapBlock)); |
aoqi@0 | 239 | #endif |
aoqi@0 | 240 | add_to_freelist(b); |
aoqi@0 | 241 | |
aoqi@0 | 242 | debug_only(if (VerifyCodeCacheOften) verify()); |
aoqi@0 | 243 | } |
aoqi@0 | 244 | |
aoqi@0 | 245 | |
aoqi@0 | 246 | void* CodeHeap::find_start(void* p) const { |
aoqi@0 | 247 | if (!contains(p)) { |
aoqi@0 | 248 | return NULL; |
aoqi@0 | 249 | } |
aoqi@0 | 250 | size_t i = segment_for(p); |
aoqi@0 | 251 | address b = (address)_segmap.low(); |
aoqi@0 | 252 | if (b[i] == 0xFF) { |
aoqi@0 | 253 | return NULL; |
aoqi@0 | 254 | } |
aoqi@0 | 255 | while (b[i] > 0) i -= (int)b[i]; |
aoqi@0 | 256 | HeapBlock* h = block_at(i); |
aoqi@0 | 257 | if (h->free()) { |
aoqi@0 | 258 | return NULL; |
aoqi@0 | 259 | } |
aoqi@0 | 260 | return h->allocated_space(); |
aoqi@0 | 261 | } |
aoqi@0 | 262 | |
aoqi@0 | 263 | |
aoqi@0 | 264 | size_t CodeHeap::alignment_unit() const { |
aoqi@0 | 265 | // this will be a power of two |
aoqi@0 | 266 | return _segment_size; |
aoqi@0 | 267 | } |
aoqi@0 | 268 | |
aoqi@0 | 269 | |
aoqi@0 | 270 | size_t CodeHeap::alignment_offset() const { |
aoqi@0 | 271 | // The lowest address in any allocated block will be |
aoqi@0 | 272 | // equal to alignment_offset (mod alignment_unit). |
aoqi@0 | 273 | return sizeof(HeapBlock) & (_segment_size - 1); |
aoqi@0 | 274 | } |
aoqi@0 | 275 | |
aoqi@0 | 276 | // Finds the next free heapblock. If the current one is free, that it returned |
aoqi@0 | 277 | void* CodeHeap::next_free(HeapBlock *b) const { |
aoqi@0 | 278 | // Since free blocks are merged, there is max. on free block |
aoqi@0 | 279 | // between two used ones |
aoqi@0 | 280 | if (b != NULL && b->free()) b = next_block(b); |
aoqi@0 | 281 | assert(b == NULL || !b->free(), "must be in use or at end of heap"); |
aoqi@0 | 282 | return (b == NULL) ? NULL : b->allocated_space(); |
aoqi@0 | 283 | } |
aoqi@0 | 284 | |
aoqi@0 | 285 | // Returns the first used HeapBlock |
aoqi@0 | 286 | HeapBlock* CodeHeap::first_block() const { |
aoqi@0 | 287 | if (_next_segment > 0) |
aoqi@0 | 288 | return block_at(0); |
aoqi@0 | 289 | return NULL; |
aoqi@0 | 290 | } |
aoqi@0 | 291 | |
aoqi@0 | 292 | HeapBlock *CodeHeap::block_start(void *q) const { |
aoqi@0 | 293 | HeapBlock* b = (HeapBlock*)find_start(q); |
aoqi@0 | 294 | if (b == NULL) return NULL; |
aoqi@0 | 295 | return b - 1; |
aoqi@0 | 296 | } |
aoqi@0 | 297 | |
aoqi@0 | 298 | // Returns the next Heap block an offset into one |
aoqi@0 | 299 | HeapBlock* CodeHeap::next_block(HeapBlock *b) const { |
aoqi@0 | 300 | if (b == NULL) return NULL; |
aoqi@0 | 301 | size_t i = segment_for(b) + b->length(); |
aoqi@0 | 302 | if (i < _next_segment) |
aoqi@0 | 303 | return block_at(i); |
aoqi@0 | 304 | return NULL; |
aoqi@0 | 305 | } |
aoqi@0 | 306 | |
aoqi@0 | 307 | |
aoqi@0 | 308 | // Returns current capacity |
aoqi@0 | 309 | size_t CodeHeap::capacity() const { |
aoqi@0 | 310 | return _memory.committed_size(); |
aoqi@0 | 311 | } |
aoqi@0 | 312 | |
aoqi@0 | 313 | size_t CodeHeap::max_capacity() const { |
aoqi@0 | 314 | return _memory.reserved_size(); |
aoqi@0 | 315 | } |
aoqi@0 | 316 | |
aoqi@0 | 317 | size_t CodeHeap::allocated_capacity() const { |
aoqi@0 | 318 | // size of used heap - size on freelist |
aoqi@0 | 319 | return segments_to_size(_next_segment - _freelist_segments); |
aoqi@0 | 320 | } |
aoqi@0 | 321 | |
aoqi@0 | 322 | // Returns size of the unallocated heap block |
aoqi@0 | 323 | size_t CodeHeap::heap_unallocated_capacity() const { |
aoqi@0 | 324 | // Total number of segments - number currently used |
aoqi@0 | 325 | return segments_to_size(_number_of_reserved_segments - _next_segment); |
aoqi@0 | 326 | } |
aoqi@0 | 327 | |
aoqi@0 | 328 | // Free list management |
aoqi@0 | 329 | |
aoqi@0 | 330 | FreeBlock *CodeHeap::following_block(FreeBlock *b) { |
aoqi@0 | 331 | return (FreeBlock*)(((address)b) + _segment_size * b->length()); |
aoqi@0 | 332 | } |
aoqi@0 | 333 | |
aoqi@0 | 334 | // Inserts block b after a |
aoqi@0 | 335 | void CodeHeap::insert_after(FreeBlock* a, FreeBlock* b) { |
aoqi@0 | 336 | assert(a != NULL && b != NULL, "must be real pointers"); |
aoqi@0 | 337 | |
aoqi@0 | 338 | // Link b into the list after a |
aoqi@0 | 339 | b->set_link(a->link()); |
aoqi@0 | 340 | a->set_link(b); |
aoqi@0 | 341 | |
aoqi@0 | 342 | // See if we can merge blocks |
aoqi@0 | 343 | merge_right(b); // Try to make b bigger |
aoqi@0 | 344 | merge_right(a); // Try to make a include b |
aoqi@0 | 345 | } |
aoqi@0 | 346 | |
aoqi@0 | 347 | // Try to merge this block with the following block |
aoqi@0 | 348 | void CodeHeap::merge_right(FreeBlock *a) { |
aoqi@0 | 349 | assert(a->free(), "must be a free block"); |
aoqi@0 | 350 | if (following_block(a) == a->link()) { |
aoqi@0 | 351 | assert(a->link() != NULL && a->link()->free(), "must be free too"); |
aoqi@0 | 352 | // Update block a to include the following block |
aoqi@0 | 353 | a->set_length(a->length() + a->link()->length()); |
aoqi@0 | 354 | a->set_link(a->link()->link()); |
aoqi@0 | 355 | // Update find_start map |
aoqi@0 | 356 | size_t beg = segment_for(a); |
aoqi@0 | 357 | mark_segmap_as_used(beg, beg + a->length()); |
aoqi@0 | 358 | } |
aoqi@0 | 359 | } |
aoqi@0 | 360 | |
aoqi@0 | 361 | void CodeHeap::add_to_freelist(HeapBlock *a) { |
aoqi@0 | 362 | FreeBlock* b = (FreeBlock*)a; |
aoqi@0 | 363 | assert(b != _freelist, "cannot be removed twice"); |
aoqi@0 | 364 | |
aoqi@0 | 365 | // Mark as free and update free space count |
aoqi@0 | 366 | _freelist_segments += b->length(); |
aoqi@0 | 367 | b->set_free(); |
aoqi@0 | 368 | |
aoqi@0 | 369 | // First element in list? |
aoqi@0 | 370 | if (_freelist == NULL) { |
aoqi@0 | 371 | _freelist = b; |
aoqi@0 | 372 | b->set_link(NULL); |
aoqi@0 | 373 | return; |
aoqi@0 | 374 | } |
aoqi@0 | 375 | |
aoqi@0 | 376 | // Scan for right place to put into list. List |
aoqi@0 | 377 | // is sorted by increasing addresseses |
aoqi@0 | 378 | FreeBlock* prev = NULL; |
aoqi@0 | 379 | FreeBlock* cur = _freelist; |
aoqi@0 | 380 | while(cur != NULL && cur < b) { |
aoqi@0 | 381 | assert(prev == NULL || prev < cur, "must be ordered"); |
aoqi@0 | 382 | prev = cur; |
aoqi@0 | 383 | cur = cur->link(); |
aoqi@0 | 384 | } |
aoqi@0 | 385 | |
aoqi@0 | 386 | assert( (prev == NULL && b < _freelist) || |
aoqi@0 | 387 | (prev < b && (cur == NULL || b < cur)), "list must be ordered"); |
aoqi@0 | 388 | |
aoqi@0 | 389 | if (prev == NULL) { |
aoqi@0 | 390 | // Insert first in list |
aoqi@0 | 391 | b->set_link(_freelist); |
aoqi@0 | 392 | _freelist = b; |
aoqi@0 | 393 | merge_right(_freelist); |
aoqi@0 | 394 | } else { |
aoqi@0 | 395 | insert_after(prev, b); |
aoqi@0 | 396 | } |
aoqi@0 | 397 | } |
aoqi@0 | 398 | |
aoqi@0 | 399 | // Search freelist for an entry on the list with the best fit |
aoqi@0 | 400 | // Return NULL if no one was found |
aoqi@0 | 401 | FreeBlock* CodeHeap::search_freelist(size_t length, bool is_critical) { |
aoqi@0 | 402 | FreeBlock *best_block = NULL; |
aoqi@0 | 403 | FreeBlock *best_prev = NULL; |
aoqi@0 | 404 | size_t best_length = 0; |
aoqi@0 | 405 | |
aoqi@0 | 406 | // Search for smallest block which is bigger than length |
aoqi@0 | 407 | FreeBlock *prev = NULL; |
aoqi@0 | 408 | FreeBlock *cur = _freelist; |
aoqi@0 | 409 | while(cur != NULL) { |
aoqi@0 | 410 | size_t l = cur->length(); |
aoqi@0 | 411 | if (l >= length && (best_block == NULL || best_length > l)) { |
aoqi@0 | 412 | |
aoqi@0 | 413 | // Non critical allocations are not allowed to use the last part of the code heap. |
aoqi@0 | 414 | if (!is_critical) { |
aoqi@0 | 415 | // Make sure the end of the allocation doesn't cross into the last part of the code heap |
aoqi@0 | 416 | if (((size_t)cur + length) > ((size_t)high_boundary() - CodeCacheMinimumFreeSpace)) { |
aoqi@0 | 417 | // the freelist is sorted by address - if one fails, all consecutive will also fail. |
aoqi@0 | 418 | break; |
aoqi@0 | 419 | } |
aoqi@0 | 420 | } |
aoqi@0 | 421 | |
aoqi@0 | 422 | // Remember best block, its previous element, and its length |
aoqi@0 | 423 | best_block = cur; |
aoqi@0 | 424 | best_prev = prev; |
aoqi@0 | 425 | best_length = best_block->length(); |
aoqi@0 | 426 | } |
aoqi@0 | 427 | |
aoqi@0 | 428 | // Next element in list |
aoqi@0 | 429 | prev = cur; |
aoqi@0 | 430 | cur = cur->link(); |
aoqi@0 | 431 | } |
aoqi@0 | 432 | |
aoqi@0 | 433 | if (best_block == NULL) { |
aoqi@0 | 434 | // None found |
aoqi@0 | 435 | return NULL; |
aoqi@0 | 436 | } |
aoqi@0 | 437 | |
aoqi@0 | 438 | assert((best_prev == NULL && _freelist == best_block ) || |
aoqi@0 | 439 | (best_prev != NULL && best_prev->link() == best_block), "sanity check"); |
aoqi@0 | 440 | |
aoqi@0 | 441 | // Exact (or at least good enough) fit. Remove from list. |
aoqi@0 | 442 | // Don't leave anything on the freelist smaller than CodeCacheMinBlockLength. |
aoqi@0 | 443 | if (best_length < length + CodeCacheMinBlockLength) { |
aoqi@0 | 444 | length = best_length; |
aoqi@0 | 445 | if (best_prev == NULL) { |
aoqi@0 | 446 | assert(_freelist == best_block, "sanity check"); |
aoqi@0 | 447 | _freelist = _freelist->link(); |
aoqi@0 | 448 | } else { |
aoqi@0 | 449 | // Unmap element |
aoqi@0 | 450 | best_prev->set_link(best_block->link()); |
aoqi@0 | 451 | } |
aoqi@0 | 452 | } else { |
aoqi@0 | 453 | // Truncate block and return a pointer to the following block |
aoqi@0 | 454 | best_block->set_length(best_length - length); |
aoqi@0 | 455 | best_block = following_block(best_block); |
aoqi@0 | 456 | // Set used bit and length on new block |
aoqi@0 | 457 | size_t beg = segment_for(best_block); |
aoqi@0 | 458 | mark_segmap_as_used(beg, beg + length); |
aoqi@0 | 459 | best_block->set_length(length); |
aoqi@0 | 460 | } |
aoqi@0 | 461 | |
aoqi@0 | 462 | best_block->set_used(); |
aoqi@0 | 463 | _freelist_segments -= length; |
aoqi@0 | 464 | return best_block; |
aoqi@0 | 465 | } |
aoqi@0 | 466 | |
aoqi@0 | 467 | //---------------------------------------------------------------------------- |
aoqi@0 | 468 | // Non-product code |
aoqi@0 | 469 | |
aoqi@0 | 470 | #ifndef PRODUCT |
aoqi@0 | 471 | |
aoqi@0 | 472 | void CodeHeap::print() { |
aoqi@0 | 473 | tty->print_cr("The Heap"); |
aoqi@0 | 474 | } |
aoqi@0 | 475 | |
aoqi@0 | 476 | #endif |
aoqi@0 | 477 | |
aoqi@0 | 478 | void CodeHeap::verify() { |
aoqi@0 | 479 | // Count the number of blocks on the freelist, and the amount of space |
aoqi@0 | 480 | // represented. |
aoqi@0 | 481 | int count = 0; |
aoqi@0 | 482 | size_t len = 0; |
aoqi@0 | 483 | for(FreeBlock* b = _freelist; b != NULL; b = b->link()) { |
aoqi@0 | 484 | len += b->length(); |
aoqi@0 | 485 | count++; |
aoqi@0 | 486 | } |
aoqi@0 | 487 | |
aoqi@0 | 488 | // Verify that freelist contains the right amount of free space |
aoqi@0 | 489 | // guarantee(len == _freelist_segments, "wrong freelist"); |
aoqi@0 | 490 | |
aoqi@0 | 491 | // Verify that the number of free blocks is not out of hand. |
aoqi@0 | 492 | static int free_block_threshold = 10000; |
aoqi@0 | 493 | if (count > free_block_threshold) { |
aoqi@0 | 494 | warning("CodeHeap: # of free blocks > %d", free_block_threshold); |
aoqi@0 | 495 | // Double the warning limit |
aoqi@0 | 496 | free_block_threshold *= 2; |
aoqi@0 | 497 | } |
aoqi@0 | 498 | |
aoqi@0 | 499 | // Verify that the freelist contains the same number of free blocks that is |
aoqi@0 | 500 | // found on the full list. |
aoqi@0 | 501 | for(HeapBlock *h = first_block(); h != NULL; h = next_block(h)) { |
aoqi@0 | 502 | if (h->free()) count--; |
aoqi@0 | 503 | } |
aoqi@0 | 504 | // guarantee(count == 0, "missing free blocks"); |
aoqi@0 | 505 | } |