Wed, 26 Jun 2013 16:58:37 +0200
8013590: NPG: Add a memory pool MXBean for Metaspace
Reviewed-by: jmasa, mgerdin
duke@435 | 1 | /* |
coleenp@4037 | 2 | * Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
stefank@2314 | 25 | #include "precompiled.hpp" |
stefank@2314 | 26 | #include "gc_interface/collectedHeap.inline.hpp" |
stefank@2314 | 27 | #include "memory/blockOffsetTable.inline.hpp" |
stefank@2314 | 28 | #include "memory/iterator.hpp" |
stefank@2314 | 29 | #include "memory/space.inline.hpp" |
stefank@2314 | 30 | #include "memory/universe.hpp" |
stefank@2314 | 31 | #include "oops/oop.inline.hpp" |
stefank@2314 | 32 | #include "runtime/java.hpp" |
zgu@3900 | 33 | #include "services/memTracker.hpp" |
duke@435 | 34 | |
duke@435 | 35 | ////////////////////////////////////////////////////////////////////// |
duke@435 | 36 | // BlockOffsetSharedArray |
duke@435 | 37 | ////////////////////////////////////////////////////////////////////// |
duke@435 | 38 | |
duke@435 | 39 | BlockOffsetSharedArray::BlockOffsetSharedArray(MemRegion reserved, |
duke@435 | 40 | size_t init_word_size): |
duke@435 | 41 | _reserved(reserved), _end(NULL) |
duke@435 | 42 | { |
duke@435 | 43 | size_t size = compute_size(reserved.word_size()); |
duke@435 | 44 | ReservedSpace rs(size); |
duke@435 | 45 | if (!rs.is_reserved()) { |
duke@435 | 46 | vm_exit_during_initialization("Could not reserve enough space for heap offset array"); |
duke@435 | 47 | } |
zgu@3900 | 48 | |
zgu@3900 | 49 | MemTracker::record_virtual_memory_type((address)rs.base(), mtGC); |
zgu@3900 | 50 | |
duke@435 | 51 | if (!_vs.initialize(rs, 0)) { |
duke@435 | 52 | vm_exit_during_initialization("Could not reserve enough space for heap offset array"); |
duke@435 | 53 | } |
duke@435 | 54 | _offset_array = (u_char*)_vs.low_boundary(); |
duke@435 | 55 | resize(init_word_size); |
duke@435 | 56 | if (TraceBlockOffsetTable) { |
duke@435 | 57 | gclog_or_tty->print_cr("BlockOffsetSharedArray::BlockOffsetSharedArray: "); |
duke@435 | 58 | gclog_or_tty->print_cr(" " |
duke@435 | 59 | " rs.base(): " INTPTR_FORMAT |
duke@435 | 60 | " rs.size(): " INTPTR_FORMAT |
duke@435 | 61 | " rs end(): " INTPTR_FORMAT, |
duke@435 | 62 | rs.base(), rs.size(), rs.base() + rs.size()); |
duke@435 | 63 | gclog_or_tty->print_cr(" " |
duke@435 | 64 | " _vs.low_boundary(): " INTPTR_FORMAT |
duke@435 | 65 | " _vs.high_boundary(): " INTPTR_FORMAT, |
duke@435 | 66 | _vs.low_boundary(), |
duke@435 | 67 | _vs.high_boundary()); |
duke@435 | 68 | } |
duke@435 | 69 | } |
duke@435 | 70 | |
duke@435 | 71 | void BlockOffsetSharedArray::resize(size_t new_word_size) { |
duke@435 | 72 | assert(new_word_size <= _reserved.word_size(), "Resize larger than reserved"); |
duke@435 | 73 | size_t new_size = compute_size(new_word_size); |
duke@435 | 74 | size_t old_size = _vs.committed_size(); |
duke@435 | 75 | size_t delta; |
duke@435 | 76 | char* high = _vs.high(); |
duke@435 | 77 | _end = _reserved.start() + new_word_size; |
duke@435 | 78 | if (new_size > old_size) { |
duke@435 | 79 | delta = ReservedSpace::page_align_size_up(new_size - old_size); |
duke@435 | 80 | assert(delta > 0, "just checking"); |
duke@435 | 81 | if (!_vs.expand_by(delta)) { |
duke@435 | 82 | // Do better than this for Merlin |
ccheung@4993 | 83 | vm_exit_out_of_memory(delta, OOM_MMAP_ERROR, "offset table expansion"); |
duke@435 | 84 | } |
duke@435 | 85 | assert(_vs.high() == high + delta, "invalid expansion"); |
duke@435 | 86 | } else { |
duke@435 | 87 | delta = ReservedSpace::page_align_size_down(old_size - new_size); |
duke@435 | 88 | if (delta == 0) return; |
duke@435 | 89 | _vs.shrink_by(delta); |
duke@435 | 90 | assert(_vs.high() == high - delta, "invalid expansion"); |
duke@435 | 91 | } |
duke@435 | 92 | } |
duke@435 | 93 | |
duke@435 | 94 | bool BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const { |
duke@435 | 95 | assert(p >= _reserved.start(), "just checking"); |
duke@435 | 96 | size_t delta = pointer_delta(p, _reserved.start()); |
duke@435 | 97 | return (delta & right_n_bits(LogN_words)) == (size_t)NoBits; |
duke@435 | 98 | } |
duke@435 | 99 | |
duke@435 | 100 | |
duke@435 | 101 | ////////////////////////////////////////////////////////////////////// |
duke@435 | 102 | // BlockOffsetArray |
duke@435 | 103 | ////////////////////////////////////////////////////////////////////// |
duke@435 | 104 | |
duke@435 | 105 | BlockOffsetArray::BlockOffsetArray(BlockOffsetSharedArray* array, |
ysr@2071 | 106 | MemRegion mr, bool init_to_zero_) : |
duke@435 | 107 | BlockOffsetTable(mr.start(), mr.end()), |
ysr@2071 | 108 | _array(array) |
duke@435 | 109 | { |
duke@435 | 110 | assert(_bottom <= _end, "arguments out of order"); |
ysr@2071 | 111 | set_init_to_zero(init_to_zero_); |
ysr@2071 | 112 | if (!init_to_zero_) { |
duke@435 | 113 | // initialize cards to point back to mr.start() |
duke@435 | 114 | set_remainder_to_point_to_start(mr.start() + N_words, mr.end()); |
duke@435 | 115 | _array->set_offset_array(0, 0); // set first card to 0 |
duke@435 | 116 | } |
duke@435 | 117 | } |
duke@435 | 118 | |
duke@435 | 119 | |
duke@435 | 120 | // The arguments follow the normal convention of denoting |
duke@435 | 121 | // a right-open interval: [start, end) |
duke@435 | 122 | void |
duke@435 | 123 | BlockOffsetArray:: |
ysr@2071 | 124 | set_remainder_to_point_to_start(HeapWord* start, HeapWord* end, bool reducing) { |
duke@435 | 125 | |
ysr@2071 | 126 | check_reducing_assertion(reducing); |
duke@435 | 127 | if (start >= end) { |
duke@435 | 128 | // The start address is equal to the end address (or to |
duke@435 | 129 | // the right of the end address) so there are not cards |
duke@435 | 130 | // that need to be updated.. |
duke@435 | 131 | return; |
duke@435 | 132 | } |
duke@435 | 133 | |
duke@435 | 134 | // Write the backskip value for each region. |
duke@435 | 135 | // |
duke@435 | 136 | // offset |
duke@435 | 137 | // card 2nd 3rd |
duke@435 | 138 | // | +- 1st | | |
duke@435 | 139 | // v v v v |
duke@435 | 140 | // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+- |
duke@435 | 141 | // |x|0|0|0|0|0|0|0|1|1|1|1|1|1| ... |1|1|1|1|2|2|2|2|2|2| ... |
duke@435 | 142 | // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+- |
duke@435 | 143 | // 11 19 75 |
duke@435 | 144 | // 12 |
duke@435 | 145 | // |
duke@435 | 146 | // offset card is the card that points to the start of an object |
duke@435 | 147 | // x - offset value of offset card |
duke@435 | 148 | // 1st - start of first logarithmic region |
duke@435 | 149 | // 0 corresponds to logarithmic value N_words + 0 and 2**(3 * 0) = 1 |
duke@435 | 150 | // 2nd - start of second logarithmic region |
duke@435 | 151 | // 1 corresponds to logarithmic value N_words + 1 and 2**(3 * 1) = 8 |
duke@435 | 152 | // 3rd - start of third logarithmic region |
duke@435 | 153 | // 2 corresponds to logarithmic value N_words + 2 and 2**(3 * 2) = 64 |
duke@435 | 154 | // |
duke@435 | 155 | // integer below the block offset entry is an example of |
duke@435 | 156 | // the index of the entry |
duke@435 | 157 | // |
duke@435 | 158 | // Given an address, |
duke@435 | 159 | // Find the index for the address |
duke@435 | 160 | // Find the block offset table entry |
duke@435 | 161 | // Convert the entry to a back slide |
duke@435 | 162 | // (e.g., with today's, offset = 0x81 => |
duke@435 | 163 | // back slip = 2**(3*(0x81 - N_words)) = 2**3) = 8 |
duke@435 | 164 | // Move back N (e.g., 8) entries and repeat with the |
duke@435 | 165 | // value of the new entry |
duke@435 | 166 | // |
duke@435 | 167 | size_t start_card = _array->index_for(start); |
duke@435 | 168 | size_t end_card = _array->index_for(end-1); |
duke@435 | 169 | assert(start ==_array->address_for_index(start_card), "Precondition"); |
duke@435 | 170 | assert(end ==_array->address_for_index(end_card)+N_words, "Precondition"); |
ysr@2071 | 171 | set_remainder_to_point_to_start_incl(start_card, end_card, reducing); // closed interval |
duke@435 | 172 | } |
duke@435 | 173 | |
duke@435 | 174 | |
duke@435 | 175 | // Unlike the normal convention in this code, the argument here denotes |
duke@435 | 176 | // a closed, inclusive interval: [start_card, end_card], cf set_remainder_to_point_to_start() |
duke@435 | 177 | // above. |
duke@435 | 178 | void |
ysr@2071 | 179 | BlockOffsetArray::set_remainder_to_point_to_start_incl(size_t start_card, size_t end_card, bool reducing) { |
ysr@2071 | 180 | |
ysr@2071 | 181 | check_reducing_assertion(reducing); |
duke@435 | 182 | if (start_card > end_card) { |
duke@435 | 183 | return; |
duke@435 | 184 | } |
duke@435 | 185 | assert(start_card > _array->index_for(_bottom), "Cannot be first card"); |
duke@435 | 186 | assert(_array->offset_array(start_card-1) <= N_words, |
duke@435 | 187 | "Offset card has an unexpected value"); |
duke@435 | 188 | size_t start_card_for_region = start_card; |
duke@435 | 189 | u_char offset = max_jubyte; |
ysr@777 | 190 | for (int i = 0; i < N_powers; i++) { |
duke@435 | 191 | // -1 so that the the card with the actual offset is counted. Another -1 |
duke@435 | 192 | // so that the reach ends in this region and not at the start |
duke@435 | 193 | // of the next. |
duke@435 | 194 | size_t reach = start_card - 1 + (power_to_cards_back(i+1) - 1); |
duke@435 | 195 | offset = N_words + i; |
duke@435 | 196 | if (reach >= end_card) { |
ysr@2071 | 197 | _array->set_offset_array(start_card_for_region, end_card, offset, reducing); |
duke@435 | 198 | start_card_for_region = reach + 1; |
duke@435 | 199 | break; |
duke@435 | 200 | } |
ysr@2071 | 201 | _array->set_offset_array(start_card_for_region, reach, offset, reducing); |
duke@435 | 202 | start_card_for_region = reach + 1; |
duke@435 | 203 | } |
duke@435 | 204 | assert(start_card_for_region > end_card, "Sanity check"); |
duke@435 | 205 | DEBUG_ONLY(check_all_cards(start_card, end_card);) |
duke@435 | 206 | } |
duke@435 | 207 | |
duke@435 | 208 | // The card-interval [start_card, end_card] is a closed interval; this |
duke@435 | 209 | // is an expensive check -- use with care and only under protection of |
duke@435 | 210 | // suitable flag. |
duke@435 | 211 | void BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const { |
duke@435 | 212 | |
duke@435 | 213 | if (end_card < start_card) { |
duke@435 | 214 | return; |
duke@435 | 215 | } |
duke@435 | 216 | guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card"); |
ysr@2071 | 217 | u_char last_entry = N_words; |
duke@435 | 218 | for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) { |
duke@435 | 219 | u_char entry = _array->offset_array(c); |
ysr@2071 | 220 | guarantee(entry >= last_entry, "Monotonicity"); |
duke@435 | 221 | if (c - start_card > power_to_cards_back(1)) { |
duke@435 | 222 | guarantee(entry > N_words, "Should be in logarithmic region"); |
duke@435 | 223 | } |
duke@435 | 224 | size_t backskip = entry_to_cards_back(entry); |
duke@435 | 225 | size_t landing_card = c - backskip; |
duke@435 | 226 | guarantee(landing_card >= (start_card - 1), "Inv"); |
duke@435 | 227 | if (landing_card >= start_card) { |
ysr@2071 | 228 | guarantee(_array->offset_array(landing_card) <= entry, "Monotonicity"); |
duke@435 | 229 | } else { |
ysr@2071 | 230 | guarantee(landing_card == (start_card - 1), "Tautology"); |
ysr@2071 | 231 | // Note that N_words is the maximum offset value |
duke@435 | 232 | guarantee(_array->offset_array(landing_card) <= N_words, "Offset value"); |
duke@435 | 233 | } |
ysr@2071 | 234 | last_entry = entry; // remember for monotonicity test |
duke@435 | 235 | } |
duke@435 | 236 | } |
duke@435 | 237 | |
duke@435 | 238 | |
duke@435 | 239 | void |
duke@435 | 240 | BlockOffsetArray::alloc_block(HeapWord* blk_start, HeapWord* blk_end) { |
duke@435 | 241 | assert(blk_start != NULL && blk_end > blk_start, |
duke@435 | 242 | "phantom block"); |
duke@435 | 243 | single_block(blk_start, blk_end); |
duke@435 | 244 | } |
duke@435 | 245 | |
duke@435 | 246 | // Action_mark - update the BOT for the block [blk_start, blk_end). |
duke@435 | 247 | // Current typical use is for splitting a block. |
duke@435 | 248 | // Action_single - udpate the BOT for an allocation. |
duke@435 | 249 | // Action_verify - BOT verification. |
duke@435 | 250 | void |
duke@435 | 251 | BlockOffsetArray::do_block_internal(HeapWord* blk_start, |
duke@435 | 252 | HeapWord* blk_end, |
ysr@2071 | 253 | Action action, bool reducing) { |
duke@435 | 254 | assert(Universe::heap()->is_in_reserved(blk_start), |
duke@435 | 255 | "reference must be into the heap"); |
duke@435 | 256 | assert(Universe::heap()->is_in_reserved(blk_end-1), |
duke@435 | 257 | "limit must be within the heap"); |
duke@435 | 258 | // This is optimized to make the test fast, assuming we only rarely |
duke@435 | 259 | // cross boundaries. |
duke@435 | 260 | uintptr_t end_ui = (uintptr_t)(blk_end - 1); |
duke@435 | 261 | uintptr_t start_ui = (uintptr_t)blk_start; |
duke@435 | 262 | // Calculate the last card boundary preceding end of blk |
duke@435 | 263 | intptr_t boundary_before_end = (intptr_t)end_ui; |
duke@435 | 264 | clear_bits(boundary_before_end, right_n_bits(LogN)); |
duke@435 | 265 | if (start_ui <= (uintptr_t)boundary_before_end) { |
duke@435 | 266 | // blk starts at or crosses a boundary |
duke@435 | 267 | // Calculate index of card on which blk begins |
duke@435 | 268 | size_t start_index = _array->index_for(blk_start); |
duke@435 | 269 | // Index of card on which blk ends |
duke@435 | 270 | size_t end_index = _array->index_for(blk_end - 1); |
duke@435 | 271 | // Start address of card on which blk begins |
duke@435 | 272 | HeapWord* boundary = _array->address_for_index(start_index); |
duke@435 | 273 | assert(boundary <= blk_start, "blk should start at or after boundary"); |
duke@435 | 274 | if (blk_start != boundary) { |
duke@435 | 275 | // blk starts strictly after boundary |
duke@435 | 276 | // adjust card boundary and start_index forward to next card |
duke@435 | 277 | boundary += N_words; |
duke@435 | 278 | start_index++; |
duke@435 | 279 | } |
duke@435 | 280 | assert(start_index <= end_index, "monotonicity of index_for()"); |
duke@435 | 281 | assert(boundary <= (HeapWord*)boundary_before_end, "tautology"); |
duke@435 | 282 | switch (action) { |
duke@435 | 283 | case Action_mark: { |
duke@435 | 284 | if (init_to_zero()) { |
ysr@2071 | 285 | _array->set_offset_array(start_index, boundary, blk_start, reducing); |
duke@435 | 286 | break; |
duke@435 | 287 | } // Else fall through to the next case |
duke@435 | 288 | } |
duke@435 | 289 | case Action_single: { |
ysr@2071 | 290 | _array->set_offset_array(start_index, boundary, blk_start, reducing); |
duke@435 | 291 | // We have finished marking the "offset card". We need to now |
duke@435 | 292 | // mark the subsequent cards that this blk spans. |
duke@435 | 293 | if (start_index < end_index) { |
duke@435 | 294 | HeapWord* rem_st = _array->address_for_index(start_index) + N_words; |
duke@435 | 295 | HeapWord* rem_end = _array->address_for_index(end_index) + N_words; |
ysr@2071 | 296 | set_remainder_to_point_to_start(rem_st, rem_end, reducing); |
duke@435 | 297 | } |
duke@435 | 298 | break; |
duke@435 | 299 | } |
duke@435 | 300 | case Action_check: { |
duke@435 | 301 | _array->check_offset_array(start_index, boundary, blk_start); |
duke@435 | 302 | // We have finished checking the "offset card". We need to now |
duke@435 | 303 | // check the subsequent cards that this blk spans. |
duke@435 | 304 | check_all_cards(start_index + 1, end_index); |
duke@435 | 305 | break; |
duke@435 | 306 | } |
duke@435 | 307 | default: |
duke@435 | 308 | ShouldNotReachHere(); |
duke@435 | 309 | } |
duke@435 | 310 | } |
duke@435 | 311 | } |
duke@435 | 312 | |
duke@435 | 313 | // The range [blk_start, blk_end) represents a single contiguous block |
duke@435 | 314 | // of storage; modify the block offset table to represent this |
duke@435 | 315 | // information; Right-open interval: [blk_start, blk_end) |
duke@435 | 316 | // NOTE: this method does _not_ adjust _unallocated_block. |
duke@435 | 317 | void |
duke@435 | 318 | BlockOffsetArray::single_block(HeapWord* blk_start, |
duke@435 | 319 | HeapWord* blk_end) { |
duke@435 | 320 | do_block_internal(blk_start, blk_end, Action_single); |
duke@435 | 321 | } |
duke@435 | 322 | |
duke@435 | 323 | void BlockOffsetArray::verify() const { |
duke@435 | 324 | // For each entry in the block offset table, verify that |
duke@435 | 325 | // the entry correctly finds the start of an object at the |
duke@435 | 326 | // first address covered by the block or to the left of that |
duke@435 | 327 | // first address. |
duke@435 | 328 | |
duke@435 | 329 | size_t next_index = 1; |
duke@435 | 330 | size_t last_index = last_active_index(); |
duke@435 | 331 | |
duke@435 | 332 | // Use for debugging. Initialize to NULL to distinguish the |
duke@435 | 333 | // first iteration through the while loop. |
duke@435 | 334 | HeapWord* last_p = NULL; |
duke@435 | 335 | HeapWord* last_start = NULL; |
duke@435 | 336 | oop last_o = NULL; |
duke@435 | 337 | |
duke@435 | 338 | while (next_index <= last_index) { |
duke@435 | 339 | // Use an address past the start of the address for |
duke@435 | 340 | // the entry. |
duke@435 | 341 | HeapWord* p = _array->address_for_index(next_index) + 1; |
duke@435 | 342 | if (p >= _end) { |
duke@435 | 343 | // That's all of the allocated block table. |
duke@435 | 344 | return; |
duke@435 | 345 | } |
duke@435 | 346 | // block_start() asserts that start <= p. |
duke@435 | 347 | HeapWord* start = block_start(p); |
duke@435 | 348 | // First check if the start is an allocated block and only |
duke@435 | 349 | // then if it is a valid object. |
duke@435 | 350 | oop o = oop(start); |
duke@435 | 351 | assert(!Universe::is_fully_initialized() || |
duke@435 | 352 | _sp->is_free_block(start) || |
duke@435 | 353 | o->is_oop_or_null(), "Bad object was found"); |
duke@435 | 354 | next_index++; |
duke@435 | 355 | last_p = p; |
duke@435 | 356 | last_start = start; |
duke@435 | 357 | last_o = o; |
duke@435 | 358 | } |
duke@435 | 359 | } |
duke@435 | 360 | |
duke@435 | 361 | ////////////////////////////////////////////////////////////////////// |
duke@435 | 362 | // BlockOffsetArrayNonContigSpace |
duke@435 | 363 | ////////////////////////////////////////////////////////////////////// |
duke@435 | 364 | |
duke@435 | 365 | // The block [blk_start, blk_end) has been allocated; |
duke@435 | 366 | // adjust the block offset table to represent this information; |
duke@435 | 367 | // NOTE: Clients of BlockOffsetArrayNonContigSpace: consider using |
duke@435 | 368 | // the somewhat more lightweight split_block() or |
duke@435 | 369 | // (when init_to_zero()) mark_block() wherever possible. |
duke@435 | 370 | // right-open interval: [blk_start, blk_end) |
duke@435 | 371 | void |
duke@435 | 372 | BlockOffsetArrayNonContigSpace::alloc_block(HeapWord* blk_start, |
duke@435 | 373 | HeapWord* blk_end) { |
duke@435 | 374 | assert(blk_start != NULL && blk_end > blk_start, |
duke@435 | 375 | "phantom block"); |
duke@435 | 376 | single_block(blk_start, blk_end); |
duke@435 | 377 | allocated(blk_start, blk_end); |
duke@435 | 378 | } |
duke@435 | 379 | |
duke@435 | 380 | // Adjust BOT to show that a previously whole block has been split |
duke@435 | 381 | // into two. We verify the BOT for the first part (prefix) and |
duke@435 | 382 | // update the BOT for the second part (suffix). |
duke@435 | 383 | // blk is the start of the block |
duke@435 | 384 | // blk_size is the size of the original block |
duke@435 | 385 | // left_blk_size is the size of the first part of the split |
duke@435 | 386 | void BlockOffsetArrayNonContigSpace::split_block(HeapWord* blk, |
duke@435 | 387 | size_t blk_size, |
duke@435 | 388 | size_t left_blk_size) { |
duke@435 | 389 | // Verify that the BOT shows [blk, blk + blk_size) to be one block. |
duke@435 | 390 | verify_single_block(blk, blk_size); |
duke@435 | 391 | // Update the BOT to indicate that [blk + left_blk_size, blk + blk_size) |
duke@435 | 392 | // is one single block. |
duke@435 | 393 | assert(blk_size > 0, "Should be positive"); |
duke@435 | 394 | assert(left_blk_size > 0, "Should be positive"); |
duke@435 | 395 | assert(left_blk_size < blk_size, "Not a split"); |
duke@435 | 396 | |
duke@435 | 397 | // Start addresses of prefix block and suffix block. |
duke@435 | 398 | HeapWord* pref_addr = blk; |
duke@435 | 399 | HeapWord* suff_addr = blk + left_blk_size; |
duke@435 | 400 | HeapWord* end_addr = blk + blk_size; |
duke@435 | 401 | |
duke@435 | 402 | // Indices for starts of prefix block and suffix block. |
duke@435 | 403 | size_t pref_index = _array->index_for(pref_addr); |
duke@435 | 404 | if (_array->address_for_index(pref_index) != pref_addr) { |
ysr@2071 | 405 | // pref_addr does not begin pref_index |
duke@435 | 406 | pref_index++; |
duke@435 | 407 | } |
duke@435 | 408 | |
duke@435 | 409 | size_t suff_index = _array->index_for(suff_addr); |
duke@435 | 410 | if (_array->address_for_index(suff_index) != suff_addr) { |
duke@435 | 411 | // suff_addr does not begin suff_index |
duke@435 | 412 | suff_index++; |
duke@435 | 413 | } |
duke@435 | 414 | |
duke@435 | 415 | // Definition: A block B, denoted [B_start, B_end) __starts__ |
duke@435 | 416 | // a card C, denoted [C_start, C_end), where C_start and C_end |
duke@435 | 417 | // are the heap addresses that card C covers, iff |
duke@435 | 418 | // B_start <= C_start < B_end. |
duke@435 | 419 | // |
duke@435 | 420 | // We say that a card C "is started by" a block B, iff |
duke@435 | 421 | // B "starts" C. |
duke@435 | 422 | // |
duke@435 | 423 | // Note that the cardinality of the set of cards {C} |
duke@435 | 424 | // started by a block B can be 0, 1, or more. |
duke@435 | 425 | // |
duke@435 | 426 | // Below, pref_index and suff_index are, respectively, the |
duke@435 | 427 | // first (least) card indices that the prefix and suffix of |
duke@435 | 428 | // the split start; end_index is one more than the index of |
duke@435 | 429 | // the last (greatest) card that blk starts. |
duke@435 | 430 | size_t end_index = _array->index_for(end_addr - 1) + 1; |
duke@435 | 431 | |
duke@435 | 432 | // Calculate the # cards that the prefix and suffix affect. |
duke@435 | 433 | size_t num_pref_cards = suff_index - pref_index; |
duke@435 | 434 | |
duke@435 | 435 | size_t num_suff_cards = end_index - suff_index; |
duke@435 | 436 | // Change the cards that need changing |
duke@435 | 437 | if (num_suff_cards > 0) { |
duke@435 | 438 | HeapWord* boundary = _array->address_for_index(suff_index); |
duke@435 | 439 | // Set the offset card for suffix block |
ysr@2071 | 440 | _array->set_offset_array(suff_index, boundary, suff_addr, true /* reducing */); |
duke@435 | 441 | // Change any further cards that need changing in the suffix |
duke@435 | 442 | if (num_pref_cards > 0) { |
duke@435 | 443 | if (num_pref_cards >= num_suff_cards) { |
duke@435 | 444 | // Unilaterally fix all of the suffix cards: closed card |
duke@435 | 445 | // index interval in args below. |
ysr@2071 | 446 | set_remainder_to_point_to_start_incl(suff_index + 1, end_index - 1, true /* reducing */); |
duke@435 | 447 | } else { |
duke@435 | 448 | // Unilaterally fix the first (num_pref_cards - 1) following |
duke@435 | 449 | // the "offset card" in the suffix block. |
duke@435 | 450 | set_remainder_to_point_to_start_incl(suff_index + 1, |
ysr@2071 | 451 | suff_index + num_pref_cards - 1, true /* reducing */); |
duke@435 | 452 | // Fix the appropriate cards in the remainder of the |
duke@435 | 453 | // suffix block -- these are the last num_pref_cards |
duke@435 | 454 | // cards in each power block of the "new" range plumbed |
duke@435 | 455 | // from suff_addr. |
duke@435 | 456 | bool more = true; |
duke@435 | 457 | uint i = 1; |
duke@435 | 458 | while (more && (i < N_powers)) { |
duke@435 | 459 | size_t back_by = power_to_cards_back(i); |
duke@435 | 460 | size_t right_index = suff_index + back_by - 1; |
duke@435 | 461 | size_t left_index = right_index - num_pref_cards + 1; |
duke@435 | 462 | if (right_index >= end_index - 1) { // last iteration |
duke@435 | 463 | right_index = end_index - 1; |
duke@435 | 464 | more = false; |
duke@435 | 465 | } |
duke@435 | 466 | if (back_by > num_pref_cards) { |
duke@435 | 467 | // Fill in the remainder of this "power block", if it |
duke@435 | 468 | // is non-null. |
duke@435 | 469 | if (left_index <= right_index) { |
duke@435 | 470 | _array->set_offset_array(left_index, right_index, |
ysr@2071 | 471 | N_words + i - 1, true /* reducing */); |
duke@435 | 472 | } else { |
duke@435 | 473 | more = false; // we are done |
duke@435 | 474 | } |
duke@435 | 475 | i++; |
duke@435 | 476 | break; |
duke@435 | 477 | } |
duke@435 | 478 | i++; |
duke@435 | 479 | } |
duke@435 | 480 | while (more && (i < N_powers)) { |
duke@435 | 481 | size_t back_by = power_to_cards_back(i); |
duke@435 | 482 | size_t right_index = suff_index + back_by - 1; |
duke@435 | 483 | size_t left_index = right_index - num_pref_cards + 1; |
duke@435 | 484 | if (right_index >= end_index - 1) { // last iteration |
duke@435 | 485 | right_index = end_index - 1; |
duke@435 | 486 | if (left_index > right_index) { |
duke@435 | 487 | break; |
duke@435 | 488 | } |
duke@435 | 489 | more = false; |
duke@435 | 490 | } |
duke@435 | 491 | assert(left_index <= right_index, "Error"); |
ysr@2071 | 492 | _array->set_offset_array(left_index, right_index, N_words + i - 1, true /* reducing */); |
duke@435 | 493 | i++; |
duke@435 | 494 | } |
duke@435 | 495 | } |
duke@435 | 496 | } // else no more cards to fix in suffix |
duke@435 | 497 | } // else nothing needs to be done |
duke@435 | 498 | // Verify that we did the right thing |
duke@435 | 499 | verify_single_block(pref_addr, left_blk_size); |
duke@435 | 500 | verify_single_block(suff_addr, blk_size - left_blk_size); |
duke@435 | 501 | } |
duke@435 | 502 | |
duke@435 | 503 | |
duke@435 | 504 | // Mark the BOT such that if [blk_start, blk_end) straddles a card |
duke@435 | 505 | // boundary, the card following the first such boundary is marked |
duke@435 | 506 | // with the appropriate offset. |
duke@435 | 507 | // NOTE: this method does _not_ adjust _unallocated_block or |
duke@435 | 508 | // any cards subsequent to the first one. |
duke@435 | 509 | void |
duke@435 | 510 | BlockOffsetArrayNonContigSpace::mark_block(HeapWord* blk_start, |
ysr@2071 | 511 | HeapWord* blk_end, bool reducing) { |
ysr@2071 | 512 | do_block_internal(blk_start, blk_end, Action_mark, reducing); |
duke@435 | 513 | } |
duke@435 | 514 | |
duke@435 | 515 | HeapWord* BlockOffsetArrayNonContigSpace::block_start_unsafe( |
duke@435 | 516 | const void* addr) const { |
duke@435 | 517 | assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); |
duke@435 | 518 | assert(_bottom <= addr && addr < _end, |
duke@435 | 519 | "addr must be covered by this Array"); |
duke@435 | 520 | // Must read this exactly once because it can be modified by parallel |
duke@435 | 521 | // allocation. |
duke@435 | 522 | HeapWord* ub = _unallocated_block; |
duke@435 | 523 | if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { |
duke@435 | 524 | assert(ub < _end, "tautology (see above)"); |
duke@435 | 525 | return ub; |
duke@435 | 526 | } |
duke@435 | 527 | |
duke@435 | 528 | // Otherwise, find the block start using the table. |
duke@435 | 529 | size_t index = _array->index_for(addr); |
duke@435 | 530 | HeapWord* q = _array->address_for_index(index); |
duke@435 | 531 | |
duke@435 | 532 | uint offset = _array->offset_array(index); // Extend u_char to uint. |
duke@435 | 533 | while (offset >= N_words) { |
duke@435 | 534 | // The excess of the offset from N_words indicates a power of Base |
duke@435 | 535 | // to go back by. |
duke@435 | 536 | size_t n_cards_back = entry_to_cards_back(offset); |
duke@435 | 537 | q -= (N_words * n_cards_back); |
ysr@2891 | 538 | assert(q >= _sp->bottom(), |
ysr@2891 | 539 | err_msg("q = " PTR_FORMAT " crossed below bottom = " PTR_FORMAT, |
ysr@2891 | 540 | q, _sp->bottom())); |
ysr@2891 | 541 | assert(q < _sp->end(), |
ysr@2891 | 542 | err_msg("q = " PTR_FORMAT " crossed above end = " PTR_FORMAT, |
ysr@2891 | 543 | q, _sp->end())); |
duke@435 | 544 | index -= n_cards_back; |
duke@435 | 545 | offset = _array->offset_array(index); |
duke@435 | 546 | } |
duke@435 | 547 | assert(offset < N_words, "offset too large"); |
duke@435 | 548 | index--; |
duke@435 | 549 | q -= offset; |
ysr@2891 | 550 | assert(q >= _sp->bottom(), |
ysr@2891 | 551 | err_msg("q = " PTR_FORMAT " crossed below bottom = " PTR_FORMAT, |
ysr@2891 | 552 | q, _sp->bottom())); |
ysr@2891 | 553 | assert(q < _sp->end(), |
ysr@2891 | 554 | err_msg("q = " PTR_FORMAT " crossed above end = " PTR_FORMAT, |
ysr@2891 | 555 | q, _sp->end())); |
duke@435 | 556 | HeapWord* n = q; |
duke@435 | 557 | |
duke@435 | 558 | while (n <= addr) { |
duke@435 | 559 | debug_only(HeapWord* last = q); // for debugging |
duke@435 | 560 | q = n; |
duke@435 | 561 | n += _sp->block_size(n); |
ysr@2891 | 562 | assert(n > q, |
ysr@2943 | 563 | err_msg("Looping at n = " PTR_FORMAT " with last = " PTR_FORMAT"," |
ysr@2943 | 564 | " while querying blk_start(" PTR_FORMAT ")" |
ysr@2943 | 565 | " on _sp = [" PTR_FORMAT "," PTR_FORMAT ")", |
ysr@2943 | 566 | n, last, addr, _sp->bottom(), _sp->end())); |
duke@435 | 567 | } |
ysr@2943 | 568 | assert(q <= addr, |
ysr@2943 | 569 | err_msg("wrong order for current (" INTPTR_FORMAT ")" " <= arg (" INTPTR_FORMAT ")", |
ysr@2943 | 570 | q, addr)); |
ysr@2943 | 571 | assert(addr <= n, |
ysr@2943 | 572 | err_msg("wrong order for arg (" INTPTR_FORMAT ") <= next (" INTPTR_FORMAT ")", |
ysr@2943 | 573 | addr, n)); |
duke@435 | 574 | return q; |
duke@435 | 575 | } |
duke@435 | 576 | |
duke@435 | 577 | HeapWord* BlockOffsetArrayNonContigSpace::block_start_careful( |
duke@435 | 578 | const void* addr) const { |
duke@435 | 579 | assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); |
duke@435 | 580 | |
duke@435 | 581 | assert(_bottom <= addr && addr < _end, |
duke@435 | 582 | "addr must be covered by this Array"); |
duke@435 | 583 | // Must read this exactly once because it can be modified by parallel |
duke@435 | 584 | // allocation. |
duke@435 | 585 | HeapWord* ub = _unallocated_block; |
duke@435 | 586 | if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { |
duke@435 | 587 | assert(ub < _end, "tautology (see above)"); |
duke@435 | 588 | return ub; |
duke@435 | 589 | } |
duke@435 | 590 | |
duke@435 | 591 | // Otherwise, find the block start using the table, but taking |
duke@435 | 592 | // care (cf block_start_unsafe() above) not to parse any objects/blocks |
duke@435 | 593 | // on the cards themsleves. |
duke@435 | 594 | size_t index = _array->index_for(addr); |
duke@435 | 595 | assert(_array->address_for_index(index) == addr, |
duke@435 | 596 | "arg should be start of card"); |
duke@435 | 597 | |
duke@435 | 598 | HeapWord* q = (HeapWord*)addr; |
duke@435 | 599 | uint offset; |
duke@435 | 600 | do { |
duke@435 | 601 | offset = _array->offset_array(index); |
duke@435 | 602 | if (offset < N_words) { |
duke@435 | 603 | q -= offset; |
duke@435 | 604 | } else { |
duke@435 | 605 | size_t n_cards_back = entry_to_cards_back(offset); |
duke@435 | 606 | q -= (n_cards_back * N_words); |
duke@435 | 607 | index -= n_cards_back; |
duke@435 | 608 | } |
duke@435 | 609 | } while (offset >= N_words); |
duke@435 | 610 | assert(q <= addr, "block start should be to left of arg"); |
duke@435 | 611 | return q; |
duke@435 | 612 | } |
duke@435 | 613 | |
duke@435 | 614 | #ifndef PRODUCT |
duke@435 | 615 | // Verification & debugging - ensure that the offset table reflects the fact |
duke@435 | 616 | // that the block [blk_start, blk_end) or [blk, blk + size) is a |
duke@435 | 617 | // single block of storage. NOTE: can't const this because of |
duke@435 | 618 | // call to non-const do_block_internal() below. |
duke@435 | 619 | void BlockOffsetArrayNonContigSpace::verify_single_block( |
duke@435 | 620 | HeapWord* blk_start, HeapWord* blk_end) { |
duke@435 | 621 | if (VerifyBlockOffsetArray) { |
duke@435 | 622 | do_block_internal(blk_start, blk_end, Action_check); |
duke@435 | 623 | } |
duke@435 | 624 | } |
duke@435 | 625 | |
duke@435 | 626 | void BlockOffsetArrayNonContigSpace::verify_single_block( |
duke@435 | 627 | HeapWord* blk, size_t size) { |
duke@435 | 628 | verify_single_block(blk, blk + size); |
duke@435 | 629 | } |
duke@435 | 630 | |
duke@435 | 631 | // Verify that the given block is before _unallocated_block |
duke@435 | 632 | void BlockOffsetArrayNonContigSpace::verify_not_unallocated( |
duke@435 | 633 | HeapWord* blk_start, HeapWord* blk_end) const { |
duke@435 | 634 | if (BlockOffsetArrayUseUnallocatedBlock) { |
duke@435 | 635 | assert(blk_start < blk_end, "Block inconsistency?"); |
duke@435 | 636 | assert(blk_end <= _unallocated_block, "_unallocated_block problem"); |
duke@435 | 637 | } |
duke@435 | 638 | } |
duke@435 | 639 | |
duke@435 | 640 | void BlockOffsetArrayNonContigSpace::verify_not_unallocated( |
duke@435 | 641 | HeapWord* blk, size_t size) const { |
duke@435 | 642 | verify_not_unallocated(blk, blk + size); |
duke@435 | 643 | } |
duke@435 | 644 | #endif // PRODUCT |
duke@435 | 645 | |
duke@435 | 646 | size_t BlockOffsetArrayNonContigSpace::last_active_index() const { |
duke@435 | 647 | if (_unallocated_block == _bottom) { |
duke@435 | 648 | return 0; |
duke@435 | 649 | } else { |
duke@435 | 650 | return _array->index_for(_unallocated_block - 1); |
duke@435 | 651 | } |
duke@435 | 652 | } |
duke@435 | 653 | |
duke@435 | 654 | ////////////////////////////////////////////////////////////////////// |
duke@435 | 655 | // BlockOffsetArrayContigSpace |
duke@435 | 656 | ////////////////////////////////////////////////////////////////////// |
duke@435 | 657 | |
duke@435 | 658 | HeapWord* BlockOffsetArrayContigSpace::block_start_unsafe(const void* addr) const { |
duke@435 | 659 | assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); |
duke@435 | 660 | |
duke@435 | 661 | // Otherwise, find the block start using the table. |
duke@435 | 662 | assert(_bottom <= addr && addr < _end, |
duke@435 | 663 | "addr must be covered by this Array"); |
duke@435 | 664 | size_t index = _array->index_for(addr); |
duke@435 | 665 | // We must make sure that the offset table entry we use is valid. If |
duke@435 | 666 | // "addr" is past the end, start at the last known one and go forward. |
duke@435 | 667 | index = MIN2(index, _next_offset_index-1); |
duke@435 | 668 | HeapWord* q = _array->address_for_index(index); |
duke@435 | 669 | |
duke@435 | 670 | uint offset = _array->offset_array(index); // Extend u_char to uint. |
duke@435 | 671 | while (offset > N_words) { |
duke@435 | 672 | // The excess of the offset from N_words indicates a power of Base |
duke@435 | 673 | // to go back by. |
duke@435 | 674 | size_t n_cards_back = entry_to_cards_back(offset); |
duke@435 | 675 | q -= (N_words * n_cards_back); |
duke@435 | 676 | assert(q >= _sp->bottom(), "Went below bottom!"); |
duke@435 | 677 | index -= n_cards_back; |
duke@435 | 678 | offset = _array->offset_array(index); |
duke@435 | 679 | } |
duke@435 | 680 | while (offset == N_words) { |
duke@435 | 681 | assert(q >= _sp->bottom(), "Went below bottom!"); |
duke@435 | 682 | q -= N_words; |
duke@435 | 683 | index--; |
duke@435 | 684 | offset = _array->offset_array(index); |
duke@435 | 685 | } |
duke@435 | 686 | assert(offset < N_words, "offset too large"); |
duke@435 | 687 | q -= offset; |
duke@435 | 688 | HeapWord* n = q; |
duke@435 | 689 | |
duke@435 | 690 | while (n <= addr) { |
duke@435 | 691 | debug_only(HeapWord* last = q); // for debugging |
duke@435 | 692 | q = n; |
duke@435 | 693 | n += _sp->block_size(n); |
duke@435 | 694 | } |
duke@435 | 695 | assert(q <= addr, "wrong order for current and arg"); |
duke@435 | 696 | assert(addr <= n, "wrong order for arg and next"); |
duke@435 | 697 | return q; |
duke@435 | 698 | } |
duke@435 | 699 | |
duke@435 | 700 | // |
duke@435 | 701 | // _next_offset_threshold |
duke@435 | 702 | // | _next_offset_index |
duke@435 | 703 | // v v |
duke@435 | 704 | // +-------+-------+-------+-------+-------+ |
duke@435 | 705 | // | i-1 | i | i+1 | i+2 | i+3 | |
duke@435 | 706 | // +-------+-------+-------+-------+-------+ |
duke@435 | 707 | // ( ^ ] |
duke@435 | 708 | // block-start |
duke@435 | 709 | // |
duke@435 | 710 | |
duke@435 | 711 | void BlockOffsetArrayContigSpace::alloc_block_work(HeapWord* blk_start, |
duke@435 | 712 | HeapWord* blk_end) { |
duke@435 | 713 | assert(blk_start != NULL && blk_end > blk_start, |
duke@435 | 714 | "phantom block"); |
duke@435 | 715 | assert(blk_end > _next_offset_threshold, |
duke@435 | 716 | "should be past threshold"); |
duke@435 | 717 | assert(blk_start <= _next_offset_threshold, |
jcoomes@1844 | 718 | "blk_start should be at or before threshold"); |
duke@435 | 719 | assert(pointer_delta(_next_offset_threshold, blk_start) <= N_words, |
duke@435 | 720 | "offset should be <= BlockOffsetSharedArray::N"); |
duke@435 | 721 | assert(Universe::heap()->is_in_reserved(blk_start), |
duke@435 | 722 | "reference must be into the heap"); |
duke@435 | 723 | assert(Universe::heap()->is_in_reserved(blk_end-1), |
duke@435 | 724 | "limit must be within the heap"); |
duke@435 | 725 | assert(_next_offset_threshold == |
duke@435 | 726 | _array->_reserved.start() + _next_offset_index*N_words, |
duke@435 | 727 | "index must agree with threshold"); |
duke@435 | 728 | |
duke@435 | 729 | debug_only(size_t orig_next_offset_index = _next_offset_index;) |
duke@435 | 730 | |
duke@435 | 731 | // Mark the card that holds the offset into the block. Note |
duke@435 | 732 | // that _next_offset_index and _next_offset_threshold are not |
duke@435 | 733 | // updated until the end of this method. |
duke@435 | 734 | _array->set_offset_array(_next_offset_index, |
duke@435 | 735 | _next_offset_threshold, |
duke@435 | 736 | blk_start); |
duke@435 | 737 | |
duke@435 | 738 | // We need to now mark the subsequent cards that this blk spans. |
duke@435 | 739 | |
duke@435 | 740 | // Index of card on which blk ends. |
duke@435 | 741 | size_t end_index = _array->index_for(blk_end - 1); |
duke@435 | 742 | |
duke@435 | 743 | // Are there more cards left to be updated? |
duke@435 | 744 | if (_next_offset_index + 1 <= end_index) { |
duke@435 | 745 | HeapWord* rem_st = _array->address_for_index(_next_offset_index + 1); |
duke@435 | 746 | // Calculate rem_end this way because end_index |
duke@435 | 747 | // may be the last valid index in the covered region. |
duke@435 | 748 | HeapWord* rem_end = _array->address_for_index(end_index) + N_words; |
duke@435 | 749 | set_remainder_to_point_to_start(rem_st, rem_end); |
duke@435 | 750 | } |
duke@435 | 751 | |
duke@435 | 752 | // _next_offset_index and _next_offset_threshold updated here. |
duke@435 | 753 | _next_offset_index = end_index + 1; |
duke@435 | 754 | // Calculate _next_offset_threshold this way because end_index |
duke@435 | 755 | // may be the last valid index in the covered region. |
ysr@2071 | 756 | _next_offset_threshold = _array->address_for_index(end_index) + N_words; |
ysr@2071 | 757 | assert(_next_offset_threshold >= blk_end, "Incorrect offset threshold"); |
duke@435 | 758 | |
duke@435 | 759 | #ifdef ASSERT |
duke@435 | 760 | // The offset can be 0 if the block starts on a boundary. That |
duke@435 | 761 | // is checked by an assertion above. |
duke@435 | 762 | size_t start_index = _array->index_for(blk_start); |
duke@435 | 763 | HeapWord* boundary = _array->address_for_index(start_index); |
duke@435 | 764 | assert((_array->offset_array(orig_next_offset_index) == 0 && |
duke@435 | 765 | blk_start == boundary) || |
duke@435 | 766 | (_array->offset_array(orig_next_offset_index) > 0 && |
duke@435 | 767 | _array->offset_array(orig_next_offset_index) <= N_words), |
duke@435 | 768 | "offset array should have been set"); |
duke@435 | 769 | for (size_t j = orig_next_offset_index + 1; j <= end_index; j++) { |
duke@435 | 770 | assert(_array->offset_array(j) > 0 && |
duke@435 | 771 | _array->offset_array(j) <= (u_char) (N_words+N_powers-1), |
duke@435 | 772 | "offset array should have been set"); |
duke@435 | 773 | } |
duke@435 | 774 | #endif |
duke@435 | 775 | } |
duke@435 | 776 | |
duke@435 | 777 | HeapWord* BlockOffsetArrayContigSpace::initialize_threshold() { |
duke@435 | 778 | assert(!Universe::heap()->is_in_reserved(_array->_offset_array), |
duke@435 | 779 | "just checking"); |
duke@435 | 780 | _next_offset_index = _array->index_for(_bottom); |
duke@435 | 781 | _next_offset_index++; |
duke@435 | 782 | _next_offset_threshold = |
duke@435 | 783 | _array->address_for_index(_next_offset_index); |
duke@435 | 784 | return _next_offset_threshold; |
duke@435 | 785 | } |
duke@435 | 786 | |
duke@435 | 787 | void BlockOffsetArrayContigSpace::zero_bottom_entry() { |
duke@435 | 788 | assert(!Universe::heap()->is_in_reserved(_array->_offset_array), |
duke@435 | 789 | "just checking"); |
duke@435 | 790 | size_t bottom_index = _array->index_for(_bottom); |
duke@435 | 791 | _array->set_offset_array(bottom_index, 0); |
duke@435 | 792 | } |
duke@435 | 793 | |
duke@435 | 794 | size_t BlockOffsetArrayContigSpace::last_active_index() const { |
duke@435 | 795 | size_t result = _next_offset_index - 1; |
duke@435 | 796 | return result >= 0 ? result : 0; |
duke@435 | 797 | } |