Mercurial > hg > truffle
annotate src/share/vm/memory/blockOffsetTable.cpp @ 3746:537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
Summary: Do a one-step look-ahead, when sweeping free or garbage blocks, to avoid overstepping sweep limit, which may become a non-block-boundary because of a heap expansion delta coalescing with a previously co-terminal free block.
Reviewed-by: brutisso, tonyp
| author | ysr |
|---|---|
| date | Mon, 23 May 2011 16:42:14 -0700 |
| parents | 7d64aa23eb96 |
| children | d2a62e0f25eb |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved. |
| 0 | 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 * | |
|
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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. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "gc_interface/collectedHeap.inline.hpp" | |
| 27 #include "memory/blockOffsetTable.inline.hpp" | |
| 28 #include "memory/iterator.hpp" | |
| 29 #include "memory/space.inline.hpp" | |
| 30 #include "memory/universe.hpp" | |
| 31 #include "oops/oop.inline.hpp" | |
| 32 #include "runtime/java.hpp" | |
| 0 | 33 |
| 34 ////////////////////////////////////////////////////////////////////// | |
| 35 // BlockOffsetSharedArray | |
| 36 ////////////////////////////////////////////////////////////////////// | |
| 37 | |
| 38 BlockOffsetSharedArray::BlockOffsetSharedArray(MemRegion reserved, | |
| 39 size_t init_word_size): | |
| 40 _reserved(reserved), _end(NULL) | |
| 41 { | |
| 42 size_t size = compute_size(reserved.word_size()); | |
| 43 ReservedSpace rs(size); | |
| 44 if (!rs.is_reserved()) { | |
| 45 vm_exit_during_initialization("Could not reserve enough space for heap offset array"); | |
| 46 } | |
| 47 if (!_vs.initialize(rs, 0)) { | |
| 48 vm_exit_during_initialization("Could not reserve enough space for heap offset array"); | |
| 49 } | |
| 50 _offset_array = (u_char*)_vs.low_boundary(); | |
| 51 resize(init_word_size); | |
| 52 if (TraceBlockOffsetTable) { | |
| 53 gclog_or_tty->print_cr("BlockOffsetSharedArray::BlockOffsetSharedArray: "); | |
| 54 gclog_or_tty->print_cr(" " | |
| 55 " rs.base(): " INTPTR_FORMAT | |
| 56 " rs.size(): " INTPTR_FORMAT | |
| 57 " rs end(): " INTPTR_FORMAT, | |
| 58 rs.base(), rs.size(), rs.base() + rs.size()); | |
| 59 gclog_or_tty->print_cr(" " | |
| 60 " _vs.low_boundary(): " INTPTR_FORMAT | |
| 61 " _vs.high_boundary(): " INTPTR_FORMAT, | |
| 62 _vs.low_boundary(), | |
| 63 _vs.high_boundary()); | |
| 64 } | |
| 65 } | |
| 66 | |
| 67 void BlockOffsetSharedArray::resize(size_t new_word_size) { | |
| 68 assert(new_word_size <= _reserved.word_size(), "Resize larger than reserved"); | |
| 69 size_t new_size = compute_size(new_word_size); | |
| 70 size_t old_size = _vs.committed_size(); | |
| 71 size_t delta; | |
| 72 char* high = _vs.high(); | |
| 73 _end = _reserved.start() + new_word_size; | |
| 74 if (new_size > old_size) { | |
| 75 delta = ReservedSpace::page_align_size_up(new_size - old_size); | |
| 76 assert(delta > 0, "just checking"); | |
| 77 if (!_vs.expand_by(delta)) { | |
| 78 // Do better than this for Merlin | |
| 79 vm_exit_out_of_memory(delta, "offset table expansion"); | |
| 80 } | |
| 81 assert(_vs.high() == high + delta, "invalid expansion"); | |
| 82 } else { | |
| 83 delta = ReservedSpace::page_align_size_down(old_size - new_size); | |
| 84 if (delta == 0) return; | |
| 85 _vs.shrink_by(delta); | |
| 86 assert(_vs.high() == high - delta, "invalid expansion"); | |
| 87 } | |
| 88 } | |
| 89 | |
| 90 bool BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const { | |
| 91 assert(p >= _reserved.start(), "just checking"); | |
| 92 size_t delta = pointer_delta(p, _reserved.start()); | |
| 93 return (delta & right_n_bits(LogN_words)) == (size_t)NoBits; | |
| 94 } | |
| 95 | |
| 96 | |
| 97 void BlockOffsetSharedArray::serialize(SerializeOopClosure* soc, | |
| 98 HeapWord* start, HeapWord* end) { | |
| 99 assert(_offset_array[0] == 0, "objects can't cross covered areas"); | |
| 100 assert(start <= end, "bad address range"); | |
| 101 size_t start_index = index_for(start); | |
| 102 size_t end_index = index_for(end-1)+1; | |
| 103 soc->do_region(&_offset_array[start_index], | |
| 104 (end_index - start_index) * sizeof(_offset_array[0])); | |
| 105 } | |
| 106 | |
| 107 ////////////////////////////////////////////////////////////////////// | |
| 108 // BlockOffsetArray | |
| 109 ////////////////////////////////////////////////////////////////////// | |
| 110 | |
| 111 BlockOffsetArray::BlockOffsetArray(BlockOffsetSharedArray* array, | |
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112 MemRegion mr, bool init_to_zero_) : |
| 0 | 113 BlockOffsetTable(mr.start(), mr.end()), |
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114 _array(array) |
| 0 | 115 { |
| 116 assert(_bottom <= _end, "arguments out of order"); | |
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117 set_init_to_zero(init_to_zero_); |
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118 if (!init_to_zero_) { |
| 0 | 119 // initialize cards to point back to mr.start() |
| 120 set_remainder_to_point_to_start(mr.start() + N_words, mr.end()); | |
| 121 _array->set_offset_array(0, 0); // set first card to 0 | |
| 122 } | |
| 123 } | |
| 124 | |
| 125 | |
| 126 // The arguments follow the normal convention of denoting | |
| 127 // a right-open interval: [start, end) | |
| 128 void | |
| 129 BlockOffsetArray:: | |
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130 set_remainder_to_point_to_start(HeapWord* start, HeapWord* end, bool reducing) { |
| 0 | 131 |
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132 check_reducing_assertion(reducing); |
| 0 | 133 if (start >= end) { |
| 134 // The start address is equal to the end address (or to | |
| 135 // the right of the end address) so there are not cards | |
| 136 // that need to be updated.. | |
| 137 return; | |
| 138 } | |
| 139 | |
| 140 // Write the backskip value for each region. | |
| 141 // | |
| 142 // offset | |
| 143 // card 2nd 3rd | |
| 144 // | +- 1st | | | |
| 145 // v v v v | |
| 146 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+- | |
| 147 // |x|0|0|0|0|0|0|0|1|1|1|1|1|1| ... |1|1|1|1|2|2|2|2|2|2| ... | |
| 148 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+- | |
| 149 // 11 19 75 | |
| 150 // 12 | |
| 151 // | |
| 152 // offset card is the card that points to the start of an object | |
| 153 // x - offset value of offset card | |
| 154 // 1st - start of first logarithmic region | |
| 155 // 0 corresponds to logarithmic value N_words + 0 and 2**(3 * 0) = 1 | |
| 156 // 2nd - start of second logarithmic region | |
| 157 // 1 corresponds to logarithmic value N_words + 1 and 2**(3 * 1) = 8 | |
| 158 // 3rd - start of third logarithmic region | |
| 159 // 2 corresponds to logarithmic value N_words + 2 and 2**(3 * 2) = 64 | |
| 160 // | |
| 161 // integer below the block offset entry is an example of | |
| 162 // the index of the entry | |
| 163 // | |
| 164 // Given an address, | |
| 165 // Find the index for the address | |
| 166 // Find the block offset table entry | |
| 167 // Convert the entry to a back slide | |
| 168 // (e.g., with today's, offset = 0x81 => | |
| 169 // back slip = 2**(3*(0x81 - N_words)) = 2**3) = 8 | |
| 170 // Move back N (e.g., 8) entries and repeat with the | |
| 171 // value of the new entry | |
| 172 // | |
| 173 size_t start_card = _array->index_for(start); | |
| 174 size_t end_card = _array->index_for(end-1); | |
| 175 assert(start ==_array->address_for_index(start_card), "Precondition"); | |
| 176 assert(end ==_array->address_for_index(end_card)+N_words, "Precondition"); | |
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177 set_remainder_to_point_to_start_incl(start_card, end_card, reducing); // closed interval |
| 0 | 178 } |
| 179 | |
| 180 | |
| 181 // Unlike the normal convention in this code, the argument here denotes | |
| 182 // a closed, inclusive interval: [start_card, end_card], cf set_remainder_to_point_to_start() | |
| 183 // above. | |
| 184 void | |
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185 BlockOffsetArray::set_remainder_to_point_to_start_incl(size_t start_card, size_t end_card, bool reducing) { |
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186 |
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187 check_reducing_assertion(reducing); |
| 0 | 188 if (start_card > end_card) { |
| 189 return; | |
| 190 } | |
| 191 assert(start_card > _array->index_for(_bottom), "Cannot be first card"); | |
| 192 assert(_array->offset_array(start_card-1) <= N_words, | |
| 193 "Offset card has an unexpected value"); | |
| 194 size_t start_card_for_region = start_card; | |
| 195 u_char offset = max_jubyte; | |
| 342 | 196 for (int i = 0; i < N_powers; i++) { |
| 0 | 197 // -1 so that the the card with the actual offset is counted. Another -1 |
| 198 // so that the reach ends in this region and not at the start | |
| 199 // of the next. | |
| 200 size_t reach = start_card - 1 + (power_to_cards_back(i+1) - 1); | |
| 201 offset = N_words + i; | |
| 202 if (reach >= end_card) { | |
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203 _array->set_offset_array(start_card_for_region, end_card, offset, reducing); |
| 0 | 204 start_card_for_region = reach + 1; |
| 205 break; | |
| 206 } | |
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207 _array->set_offset_array(start_card_for_region, reach, offset, reducing); |
| 0 | 208 start_card_for_region = reach + 1; |
| 209 } | |
| 210 assert(start_card_for_region > end_card, "Sanity check"); | |
| 211 DEBUG_ONLY(check_all_cards(start_card, end_card);) | |
| 212 } | |
| 213 | |
| 214 // The card-interval [start_card, end_card] is a closed interval; this | |
| 215 // is an expensive check -- use with care and only under protection of | |
| 216 // suitable flag. | |
| 217 void BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const { | |
| 218 | |
| 219 if (end_card < start_card) { | |
| 220 return; | |
| 221 } | |
| 222 guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card"); | |
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223 u_char last_entry = N_words; |
| 0 | 224 for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) { |
| 225 u_char entry = _array->offset_array(c); | |
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226 guarantee(entry >= last_entry, "Monotonicity"); |
| 0 | 227 if (c - start_card > power_to_cards_back(1)) { |
| 228 guarantee(entry > N_words, "Should be in logarithmic region"); | |
| 229 } | |
| 230 size_t backskip = entry_to_cards_back(entry); | |
| 231 size_t landing_card = c - backskip; | |
| 232 guarantee(landing_card >= (start_card - 1), "Inv"); | |
| 233 if (landing_card >= start_card) { | |
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234 guarantee(_array->offset_array(landing_card) <= entry, "Monotonicity"); |
| 0 | 235 } else { |
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236 guarantee(landing_card == (start_card - 1), "Tautology"); |
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237 // Note that N_words is the maximum offset value |
| 0 | 238 guarantee(_array->offset_array(landing_card) <= N_words, "Offset value"); |
| 239 } | |
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240 last_entry = entry; // remember for monotonicity test |
| 0 | 241 } |
| 242 } | |
| 243 | |
| 244 | |
| 245 void | |
| 246 BlockOffsetArray::alloc_block(HeapWord* blk_start, HeapWord* blk_end) { | |
| 247 assert(blk_start != NULL && blk_end > blk_start, | |
| 248 "phantom block"); | |
| 249 single_block(blk_start, blk_end); | |
| 250 } | |
| 251 | |
| 252 // Action_mark - update the BOT for the block [blk_start, blk_end). | |
| 253 // Current typical use is for splitting a block. | |
| 254 // Action_single - udpate the BOT for an allocation. | |
| 255 // Action_verify - BOT verification. | |
| 256 void | |
| 257 BlockOffsetArray::do_block_internal(HeapWord* blk_start, | |
| 258 HeapWord* blk_end, | |
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259 Action action, bool reducing) { |
| 0 | 260 assert(Universe::heap()->is_in_reserved(blk_start), |
| 261 "reference must be into the heap"); | |
| 262 assert(Universe::heap()->is_in_reserved(blk_end-1), | |
| 263 "limit must be within the heap"); | |
| 264 // This is optimized to make the test fast, assuming we only rarely | |
| 265 // cross boundaries. | |
| 266 uintptr_t end_ui = (uintptr_t)(blk_end - 1); | |
| 267 uintptr_t start_ui = (uintptr_t)blk_start; | |
| 268 // Calculate the last card boundary preceding end of blk | |
| 269 intptr_t boundary_before_end = (intptr_t)end_ui; | |
| 270 clear_bits(boundary_before_end, right_n_bits(LogN)); | |
| 271 if (start_ui <= (uintptr_t)boundary_before_end) { | |
| 272 // blk starts at or crosses a boundary | |
| 273 // Calculate index of card on which blk begins | |
| 274 size_t start_index = _array->index_for(blk_start); | |
| 275 // Index of card on which blk ends | |
| 276 size_t end_index = _array->index_for(blk_end - 1); | |
| 277 // Start address of card on which blk begins | |
| 278 HeapWord* boundary = _array->address_for_index(start_index); | |
| 279 assert(boundary <= blk_start, "blk should start at or after boundary"); | |
| 280 if (blk_start != boundary) { | |
| 281 // blk starts strictly after boundary | |
| 282 // adjust card boundary and start_index forward to next card | |
| 283 boundary += N_words; | |
| 284 start_index++; | |
| 285 } | |
| 286 assert(start_index <= end_index, "monotonicity of index_for()"); | |
| 287 assert(boundary <= (HeapWord*)boundary_before_end, "tautology"); | |
| 288 switch (action) { | |
| 289 case Action_mark: { | |
| 290 if (init_to_zero()) { | |
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291 _array->set_offset_array(start_index, boundary, blk_start, reducing); |
| 0 | 292 break; |
| 293 } // Else fall through to the next case | |
| 294 } | |
| 295 case Action_single: { | |
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296 _array->set_offset_array(start_index, boundary, blk_start, reducing); |
| 0 | 297 // We have finished marking the "offset card". We need to now |
| 298 // mark the subsequent cards that this blk spans. | |
| 299 if (start_index < end_index) { | |
| 300 HeapWord* rem_st = _array->address_for_index(start_index) + N_words; | |
| 301 HeapWord* rem_end = _array->address_for_index(end_index) + N_words; | |
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302 set_remainder_to_point_to_start(rem_st, rem_end, reducing); |
| 0 | 303 } |
| 304 break; | |
| 305 } | |
| 306 case Action_check: { | |
| 307 _array->check_offset_array(start_index, boundary, blk_start); | |
| 308 // We have finished checking the "offset card". We need to now | |
| 309 // check the subsequent cards that this blk spans. | |
| 310 check_all_cards(start_index + 1, end_index); | |
| 311 break; | |
| 312 } | |
| 313 default: | |
| 314 ShouldNotReachHere(); | |
| 315 } | |
| 316 } | |
| 317 } | |
| 318 | |
| 319 // The range [blk_start, blk_end) represents a single contiguous block | |
| 320 // of storage; modify the block offset table to represent this | |
| 321 // information; Right-open interval: [blk_start, blk_end) | |
| 322 // NOTE: this method does _not_ adjust _unallocated_block. | |
| 323 void | |
| 324 BlockOffsetArray::single_block(HeapWord* blk_start, | |
| 325 HeapWord* blk_end) { | |
| 326 do_block_internal(blk_start, blk_end, Action_single); | |
| 327 } | |
| 328 | |
| 329 void BlockOffsetArray::verify() const { | |
| 330 // For each entry in the block offset table, verify that | |
| 331 // the entry correctly finds the start of an object at the | |
| 332 // first address covered by the block or to the left of that | |
| 333 // first address. | |
| 334 | |
| 335 size_t next_index = 1; | |
| 336 size_t last_index = last_active_index(); | |
| 337 | |
| 338 // Use for debugging. Initialize to NULL to distinguish the | |
| 339 // first iteration through the while loop. | |
| 340 HeapWord* last_p = NULL; | |
| 341 HeapWord* last_start = NULL; | |
| 342 oop last_o = NULL; | |
| 343 | |
| 344 while (next_index <= last_index) { | |
| 345 // Use an address past the start of the address for | |
| 346 // the entry. | |
| 347 HeapWord* p = _array->address_for_index(next_index) + 1; | |
| 348 if (p >= _end) { | |
| 349 // That's all of the allocated block table. | |
| 350 return; | |
| 351 } | |
| 352 // block_start() asserts that start <= p. | |
| 353 HeapWord* start = block_start(p); | |
| 354 // First check if the start is an allocated block and only | |
| 355 // then if it is a valid object. | |
| 356 oop o = oop(start); | |
| 357 assert(!Universe::is_fully_initialized() || | |
| 358 _sp->is_free_block(start) || | |
| 359 o->is_oop_or_null(), "Bad object was found"); | |
| 360 next_index++; | |
| 361 last_p = p; | |
| 362 last_start = start; | |
| 363 last_o = o; | |
| 364 } | |
| 365 } | |
| 366 | |
| 367 ////////////////////////////////////////////////////////////////////// | |
| 368 // BlockOffsetArrayNonContigSpace | |
| 369 ////////////////////////////////////////////////////////////////////// | |
| 370 | |
| 371 // The block [blk_start, blk_end) has been allocated; | |
| 372 // adjust the block offset table to represent this information; | |
| 373 // NOTE: Clients of BlockOffsetArrayNonContigSpace: consider using | |
| 374 // the somewhat more lightweight split_block() or | |
| 375 // (when init_to_zero()) mark_block() wherever possible. | |
| 376 // right-open interval: [blk_start, blk_end) | |
| 377 void | |
| 378 BlockOffsetArrayNonContigSpace::alloc_block(HeapWord* blk_start, | |
| 379 HeapWord* blk_end) { | |
| 380 assert(blk_start != NULL && blk_end > blk_start, | |
| 381 "phantom block"); | |
| 382 single_block(blk_start, blk_end); | |
| 383 allocated(blk_start, blk_end); | |
| 384 } | |
| 385 | |
| 386 // Adjust BOT to show that a previously whole block has been split | |
| 387 // into two. We verify the BOT for the first part (prefix) and | |
| 388 // update the BOT for the second part (suffix). | |
| 389 // blk is the start of the block | |
| 390 // blk_size is the size of the original block | |
| 391 // left_blk_size is the size of the first part of the split | |
| 392 void BlockOffsetArrayNonContigSpace::split_block(HeapWord* blk, | |
| 393 size_t blk_size, | |
| 394 size_t left_blk_size) { | |
| 395 // Verify that the BOT shows [blk, blk + blk_size) to be one block. | |
| 396 verify_single_block(blk, blk_size); | |
| 397 // Update the BOT to indicate that [blk + left_blk_size, blk + blk_size) | |
| 398 // is one single block. | |
| 399 assert(blk_size > 0, "Should be positive"); | |
| 400 assert(left_blk_size > 0, "Should be positive"); | |
| 401 assert(left_blk_size < blk_size, "Not a split"); | |
| 402 | |
| 403 // Start addresses of prefix block and suffix block. | |
| 404 HeapWord* pref_addr = blk; | |
| 405 HeapWord* suff_addr = blk + left_blk_size; | |
| 406 HeapWord* end_addr = blk + blk_size; | |
| 407 | |
| 408 // Indices for starts of prefix block and suffix block. | |
| 409 size_t pref_index = _array->index_for(pref_addr); | |
| 410 if (_array->address_for_index(pref_index) != pref_addr) { | |
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411 // pref_addr does not begin pref_index |
| 0 | 412 pref_index++; |
| 413 } | |
| 414 | |
| 415 size_t suff_index = _array->index_for(suff_addr); | |
| 416 if (_array->address_for_index(suff_index) != suff_addr) { | |
| 417 // suff_addr does not begin suff_index | |
| 418 suff_index++; | |
| 419 } | |
| 420 | |
| 421 // Definition: A block B, denoted [B_start, B_end) __starts__ | |
| 422 // a card C, denoted [C_start, C_end), where C_start and C_end | |
| 423 // are the heap addresses that card C covers, iff | |
| 424 // B_start <= C_start < B_end. | |
| 425 // | |
| 426 // We say that a card C "is started by" a block B, iff | |
| 427 // B "starts" C. | |
| 428 // | |
| 429 // Note that the cardinality of the set of cards {C} | |
| 430 // started by a block B can be 0, 1, or more. | |
| 431 // | |
| 432 // Below, pref_index and suff_index are, respectively, the | |
| 433 // first (least) card indices that the prefix and suffix of | |
| 434 // the split start; end_index is one more than the index of | |
| 435 // the last (greatest) card that blk starts. | |
| 436 size_t end_index = _array->index_for(end_addr - 1) + 1; | |
| 437 | |
| 438 // Calculate the # cards that the prefix and suffix affect. | |
| 439 size_t num_pref_cards = suff_index - pref_index; | |
| 440 | |
| 441 size_t num_suff_cards = end_index - suff_index; | |
| 442 // Change the cards that need changing | |
| 443 if (num_suff_cards > 0) { | |
| 444 HeapWord* boundary = _array->address_for_index(suff_index); | |
| 445 // Set the offset card for suffix block | |
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446 _array->set_offset_array(suff_index, boundary, suff_addr, true /* reducing */); |
| 0 | 447 // Change any further cards that need changing in the suffix |
| 448 if (num_pref_cards > 0) { | |
| 449 if (num_pref_cards >= num_suff_cards) { | |
| 450 // Unilaterally fix all of the suffix cards: closed card | |
| 451 // index interval in args below. | |
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452 set_remainder_to_point_to_start_incl(suff_index + 1, end_index - 1, true /* reducing */); |
| 0 | 453 } else { |
| 454 // Unilaterally fix the first (num_pref_cards - 1) following | |
| 455 // the "offset card" in the suffix block. | |
| 456 set_remainder_to_point_to_start_incl(suff_index + 1, | |
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457 suff_index + num_pref_cards - 1, true /* reducing */); |
| 0 | 458 // Fix the appropriate cards in the remainder of the |
| 459 // suffix block -- these are the last num_pref_cards | |
| 460 // cards in each power block of the "new" range plumbed | |
| 461 // from suff_addr. | |
| 462 bool more = true; | |
| 463 uint i = 1; | |
| 464 while (more && (i < N_powers)) { | |
| 465 size_t back_by = power_to_cards_back(i); | |
| 466 size_t right_index = suff_index + back_by - 1; | |
| 467 size_t left_index = right_index - num_pref_cards + 1; | |
| 468 if (right_index >= end_index - 1) { // last iteration | |
| 469 right_index = end_index - 1; | |
| 470 more = false; | |
| 471 } | |
| 472 if (back_by > num_pref_cards) { | |
| 473 // Fill in the remainder of this "power block", if it | |
| 474 // is non-null. | |
| 475 if (left_index <= right_index) { | |
| 476 _array->set_offset_array(left_index, right_index, | |
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477 N_words + i - 1, true /* reducing */); |
| 0 | 478 } else { |
| 479 more = false; // we are done | |
| 480 } | |
| 481 i++; | |
| 482 break; | |
| 483 } | |
| 484 i++; | |
| 485 } | |
| 486 while (more && (i < N_powers)) { | |
| 487 size_t back_by = power_to_cards_back(i); | |
| 488 size_t right_index = suff_index + back_by - 1; | |
| 489 size_t left_index = right_index - num_pref_cards + 1; | |
| 490 if (right_index >= end_index - 1) { // last iteration | |
| 491 right_index = end_index - 1; | |
| 492 if (left_index > right_index) { | |
| 493 break; | |
| 494 } | |
| 495 more = false; | |
| 496 } | |
| 497 assert(left_index <= right_index, "Error"); | |
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498 _array->set_offset_array(left_index, right_index, N_words + i - 1, true /* reducing */); |
| 0 | 499 i++; |
| 500 } | |
| 501 } | |
| 502 } // else no more cards to fix in suffix | |
| 503 } // else nothing needs to be done | |
| 504 // Verify that we did the right thing | |
| 505 verify_single_block(pref_addr, left_blk_size); | |
| 506 verify_single_block(suff_addr, blk_size - left_blk_size); | |
| 507 } | |
| 508 | |
| 509 | |
| 510 // Mark the BOT such that if [blk_start, blk_end) straddles a card | |
| 511 // boundary, the card following the first such boundary is marked | |
| 512 // with the appropriate offset. | |
| 513 // NOTE: this method does _not_ adjust _unallocated_block or | |
| 514 // any cards subsequent to the first one. | |
| 515 void | |
| 516 BlockOffsetArrayNonContigSpace::mark_block(HeapWord* blk_start, | |
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517 HeapWord* blk_end, bool reducing) { |
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518 do_block_internal(blk_start, blk_end, Action_mark, reducing); |
| 0 | 519 } |
| 520 | |
| 521 HeapWord* BlockOffsetArrayNonContigSpace::block_start_unsafe( | |
| 522 const void* addr) const { | |
| 523 assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); | |
| 524 assert(_bottom <= addr && addr < _end, | |
| 525 "addr must be covered by this Array"); | |
| 526 // Must read this exactly once because it can be modified by parallel | |
| 527 // allocation. | |
| 528 HeapWord* ub = _unallocated_block; | |
| 529 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { | |
| 530 assert(ub < _end, "tautology (see above)"); | |
| 531 return ub; | |
| 532 } | |
| 533 | |
| 534 // Otherwise, find the block start using the table. | |
| 535 size_t index = _array->index_for(addr); | |
| 536 HeapWord* q = _array->address_for_index(index); | |
| 537 | |
| 538 uint offset = _array->offset_array(index); // Extend u_char to uint. | |
| 539 while (offset >= N_words) { | |
| 540 // The excess of the offset from N_words indicates a power of Base | |
| 541 // to go back by. | |
| 542 size_t n_cards_back = entry_to_cards_back(offset); | |
| 543 q -= (N_words * n_cards_back); | |
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544 assert(q >= _sp->bottom(), |
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545 err_msg("q = " PTR_FORMAT " crossed below bottom = " PTR_FORMAT, |
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546 q, _sp->bottom())); |
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547 assert(q < _sp->end(), |
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548 err_msg("q = " PTR_FORMAT " crossed above end = " PTR_FORMAT, |
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549 q, _sp->end())); |
| 0 | 550 index -= n_cards_back; |
| 551 offset = _array->offset_array(index); | |
| 552 } | |
| 553 assert(offset < N_words, "offset too large"); | |
| 554 index--; | |
| 555 q -= offset; | |
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556 assert(q >= _sp->bottom(), |
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557 err_msg("q = " PTR_FORMAT " crossed below bottom = " PTR_FORMAT, |
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558 q, _sp->bottom())); |
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559 assert(q < _sp->end(), |
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560 err_msg("q = " PTR_FORMAT " crossed above end = " PTR_FORMAT, |
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561 q, _sp->end())); |
| 0 | 562 HeapWord* n = q; |
| 563 | |
| 564 while (n <= addr) { | |
| 565 debug_only(HeapWord* last = q); // for debugging | |
| 566 q = n; | |
| 567 n += _sp->block_size(n); | |
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568 assert(n > q, |
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569 err_msg("Looping at n = " PTR_FORMAT " with last = " PTR_FORMAT"," |
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570 " while querying blk_start(" PTR_FORMAT ")" |
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571 " on _sp = [" PTR_FORMAT "," PTR_FORMAT ")", |
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572 n, last, addr, _sp->bottom(), _sp->end())); |
| 0 | 573 } |
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574 assert(q <= addr, |
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575 err_msg("wrong order for current (" INTPTR_FORMAT ")" " <= arg (" INTPTR_FORMAT ")", |
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576 q, addr)); |
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577 assert(addr <= n, |
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578 err_msg("wrong order for arg (" INTPTR_FORMAT ") <= next (" INTPTR_FORMAT ")", |
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579 addr, n)); |
| 0 | 580 return q; |
| 581 } | |
| 582 | |
| 583 HeapWord* BlockOffsetArrayNonContigSpace::block_start_careful( | |
| 584 const void* addr) const { | |
| 585 assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); | |
| 586 | |
| 587 assert(_bottom <= addr && addr < _end, | |
| 588 "addr must be covered by this Array"); | |
| 589 // Must read this exactly once because it can be modified by parallel | |
| 590 // allocation. | |
| 591 HeapWord* ub = _unallocated_block; | |
| 592 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { | |
| 593 assert(ub < _end, "tautology (see above)"); | |
| 594 return ub; | |
| 595 } | |
| 596 | |
| 597 // Otherwise, find the block start using the table, but taking | |
| 598 // care (cf block_start_unsafe() above) not to parse any objects/blocks | |
| 599 // on the cards themsleves. | |
| 600 size_t index = _array->index_for(addr); | |
| 601 assert(_array->address_for_index(index) == addr, | |
| 602 "arg should be start of card"); | |
| 603 | |
| 604 HeapWord* q = (HeapWord*)addr; | |
| 605 uint offset; | |
| 606 do { | |
| 607 offset = _array->offset_array(index); | |
| 608 if (offset < N_words) { | |
| 609 q -= offset; | |
| 610 } else { | |
| 611 size_t n_cards_back = entry_to_cards_back(offset); | |
| 612 q -= (n_cards_back * N_words); | |
| 613 index -= n_cards_back; | |
| 614 } | |
| 615 } while (offset >= N_words); | |
| 616 assert(q <= addr, "block start should be to left of arg"); | |
| 617 return q; | |
| 618 } | |
| 619 | |
| 620 #ifndef PRODUCT | |
| 621 // Verification & debugging - ensure that the offset table reflects the fact | |
| 622 // that the block [blk_start, blk_end) or [blk, blk + size) is a | |
| 623 // single block of storage. NOTE: can't const this because of | |
| 624 // call to non-const do_block_internal() below. | |
| 625 void BlockOffsetArrayNonContigSpace::verify_single_block( | |
| 626 HeapWord* blk_start, HeapWord* blk_end) { | |
| 627 if (VerifyBlockOffsetArray) { | |
| 628 do_block_internal(blk_start, blk_end, Action_check); | |
| 629 } | |
| 630 } | |
| 631 | |
| 632 void BlockOffsetArrayNonContigSpace::verify_single_block( | |
| 633 HeapWord* blk, size_t size) { | |
| 634 verify_single_block(blk, blk + size); | |
| 635 } | |
| 636 | |
| 637 // Verify that the given block is before _unallocated_block | |
| 638 void BlockOffsetArrayNonContigSpace::verify_not_unallocated( | |
| 639 HeapWord* blk_start, HeapWord* blk_end) const { | |
| 640 if (BlockOffsetArrayUseUnallocatedBlock) { | |
| 641 assert(blk_start < blk_end, "Block inconsistency?"); | |
| 642 assert(blk_end <= _unallocated_block, "_unallocated_block problem"); | |
| 643 } | |
| 644 } | |
| 645 | |
| 646 void BlockOffsetArrayNonContigSpace::verify_not_unallocated( | |
| 647 HeapWord* blk, size_t size) const { | |
| 648 verify_not_unallocated(blk, blk + size); | |
| 649 } | |
| 650 #endif // PRODUCT | |
| 651 | |
| 652 size_t BlockOffsetArrayNonContigSpace::last_active_index() const { | |
| 653 if (_unallocated_block == _bottom) { | |
| 654 return 0; | |
| 655 } else { | |
| 656 return _array->index_for(_unallocated_block - 1); | |
| 657 } | |
| 658 } | |
| 659 | |
| 660 ////////////////////////////////////////////////////////////////////// | |
| 661 // BlockOffsetArrayContigSpace | |
| 662 ////////////////////////////////////////////////////////////////////// | |
| 663 | |
| 664 HeapWord* BlockOffsetArrayContigSpace::block_start_unsafe(const void* addr) const { | |
| 665 assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); | |
| 666 | |
| 667 // Otherwise, find the block start using the table. | |
| 668 assert(_bottom <= addr && addr < _end, | |
| 669 "addr must be covered by this Array"); | |
| 670 size_t index = _array->index_for(addr); | |
| 671 // We must make sure that the offset table entry we use is valid. If | |
| 672 // "addr" is past the end, start at the last known one and go forward. | |
| 673 index = MIN2(index, _next_offset_index-1); | |
| 674 HeapWord* q = _array->address_for_index(index); | |
| 675 | |
| 676 uint offset = _array->offset_array(index); // Extend u_char to uint. | |
| 677 while (offset > N_words) { | |
| 678 // The excess of the offset from N_words indicates a power of Base | |
| 679 // to go back by. | |
| 680 size_t n_cards_back = entry_to_cards_back(offset); | |
| 681 q -= (N_words * n_cards_back); | |
| 682 assert(q >= _sp->bottom(), "Went below bottom!"); | |
| 683 index -= n_cards_back; | |
| 684 offset = _array->offset_array(index); | |
| 685 } | |
| 686 while (offset == N_words) { | |
| 687 assert(q >= _sp->bottom(), "Went below bottom!"); | |
| 688 q -= N_words; | |
| 689 index--; | |
| 690 offset = _array->offset_array(index); | |
| 691 } | |
| 692 assert(offset < N_words, "offset too large"); | |
| 693 q -= offset; | |
| 694 HeapWord* n = q; | |
| 695 | |
| 696 while (n <= addr) { | |
| 697 debug_only(HeapWord* last = q); // for debugging | |
| 698 q = n; | |
| 699 n += _sp->block_size(n); | |
| 700 } | |
| 701 assert(q <= addr, "wrong order for current and arg"); | |
| 702 assert(addr <= n, "wrong order for arg and next"); | |
| 703 return q; | |
| 704 } | |
| 705 | |
| 706 // | |
| 707 // _next_offset_threshold | |
| 708 // | _next_offset_index | |
| 709 // v v | |
| 710 // +-------+-------+-------+-------+-------+ | |
| 711 // | i-1 | i | i+1 | i+2 | i+3 | | |
| 712 // +-------+-------+-------+-------+-------+ | |
| 713 // ( ^ ] | |
| 714 // block-start | |
| 715 // | |
| 716 | |
| 717 void BlockOffsetArrayContigSpace::alloc_block_work(HeapWord* blk_start, | |
| 718 HeapWord* blk_end) { | |
| 719 assert(blk_start != NULL && blk_end > blk_start, | |
| 720 "phantom block"); | |
| 721 assert(blk_end > _next_offset_threshold, | |
| 722 "should be past threshold"); | |
| 723 assert(blk_start <= _next_offset_threshold, | |
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724 "blk_start should be at or before threshold"); |
| 0 | 725 assert(pointer_delta(_next_offset_threshold, blk_start) <= N_words, |
| 726 "offset should be <= BlockOffsetSharedArray::N"); | |
| 727 assert(Universe::heap()->is_in_reserved(blk_start), | |
| 728 "reference must be into the heap"); | |
| 729 assert(Universe::heap()->is_in_reserved(blk_end-1), | |
| 730 "limit must be within the heap"); | |
| 731 assert(_next_offset_threshold == | |
| 732 _array->_reserved.start() + _next_offset_index*N_words, | |
| 733 "index must agree with threshold"); | |
| 734 | |
| 735 debug_only(size_t orig_next_offset_index = _next_offset_index;) | |
| 736 | |
| 737 // Mark the card that holds the offset into the block. Note | |
| 738 // that _next_offset_index and _next_offset_threshold are not | |
| 739 // updated until the end of this method. | |
| 740 _array->set_offset_array(_next_offset_index, | |
| 741 _next_offset_threshold, | |
| 742 blk_start); | |
| 743 | |
| 744 // We need to now mark the subsequent cards that this blk spans. | |
| 745 | |
| 746 // Index of card on which blk ends. | |
| 747 size_t end_index = _array->index_for(blk_end - 1); | |
| 748 | |
| 749 // Are there more cards left to be updated? | |
| 750 if (_next_offset_index + 1 <= end_index) { | |
| 751 HeapWord* rem_st = _array->address_for_index(_next_offset_index + 1); | |
| 752 // Calculate rem_end this way because end_index | |
| 753 // may be the last valid index in the covered region. | |
| 754 HeapWord* rem_end = _array->address_for_index(end_index) + N_words; | |
| 755 set_remainder_to_point_to_start(rem_st, rem_end); | |
| 756 } | |
| 757 | |
| 758 // _next_offset_index and _next_offset_threshold updated here. | |
| 759 _next_offset_index = end_index + 1; | |
| 760 // Calculate _next_offset_threshold this way because end_index | |
| 761 // may be the last valid index in the covered region. | |
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762 _next_offset_threshold = _array->address_for_index(end_index) + N_words; |
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changeset
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763 assert(_next_offset_threshold >= blk_end, "Incorrect offset threshold"); |
| 0 | 764 |
| 765 #ifdef ASSERT | |
| 766 // The offset can be 0 if the block starts on a boundary. That | |
| 767 // is checked by an assertion above. | |
| 768 size_t start_index = _array->index_for(blk_start); | |
| 769 HeapWord* boundary = _array->address_for_index(start_index); | |
| 770 assert((_array->offset_array(orig_next_offset_index) == 0 && | |
| 771 blk_start == boundary) || | |
| 772 (_array->offset_array(orig_next_offset_index) > 0 && | |
| 773 _array->offset_array(orig_next_offset_index) <= N_words), | |
| 774 "offset array should have been set"); | |
| 775 for (size_t j = orig_next_offset_index + 1; j <= end_index; j++) { | |
| 776 assert(_array->offset_array(j) > 0 && | |
| 777 _array->offset_array(j) <= (u_char) (N_words+N_powers-1), | |
| 778 "offset array should have been set"); | |
| 779 } | |
| 780 #endif | |
| 781 } | |
| 782 | |
| 783 HeapWord* BlockOffsetArrayContigSpace::initialize_threshold() { | |
| 784 assert(!Universe::heap()->is_in_reserved(_array->_offset_array), | |
| 785 "just checking"); | |
| 786 _next_offset_index = _array->index_for(_bottom); | |
| 787 _next_offset_index++; | |
| 788 _next_offset_threshold = | |
| 789 _array->address_for_index(_next_offset_index); | |
| 790 return _next_offset_threshold; | |
| 791 } | |
| 792 | |
| 793 void BlockOffsetArrayContigSpace::zero_bottom_entry() { | |
| 794 assert(!Universe::heap()->is_in_reserved(_array->_offset_array), | |
| 795 "just checking"); | |
| 796 size_t bottom_index = _array->index_for(_bottom); | |
| 797 _array->set_offset_array(bottom_index, 0); | |
| 798 } | |
| 799 | |
| 800 | |
| 801 void BlockOffsetArrayContigSpace::serialize(SerializeOopClosure* soc) { | |
| 802 if (soc->reading()) { | |
| 803 // Null these values so that the serializer won't object to updating them. | |
| 804 _next_offset_threshold = NULL; | |
| 805 _next_offset_index = 0; | |
| 806 } | |
| 807 soc->do_ptr(&_next_offset_threshold); | |
| 808 soc->do_size_t(&_next_offset_index); | |
| 809 } | |
| 810 | |
| 811 size_t BlockOffsetArrayContigSpace::last_active_index() const { | |
| 812 size_t result = _next_offset_index - 1; | |
| 813 return result >= 0 ? result : 0; | |
| 814 } |