1 /*
2 * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
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 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
27 #include "gc_implementation/g1/heapRegion.hpp"
28 #include "memory/space.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "runtime/java.hpp"
31 #include "services/memTracker.hpp"
32
33 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
34
35 //////////////////////////////////////////////////////////////////////
36 // G1BlockOffsetSharedArray
37 //////////////////////////////////////////////////////////////////////
38
39 G1BlockOffsetSharedArray::G1BlockOffsetSharedArray(MemRegion reserved,
40 size_t init_word_size) :
41 _reserved(reserved), _end(NULL)
42 {
43 size_t size = compute_size(reserved.word_size());
44 ReservedSpace rs(ReservedSpace::allocation_align_size_up(size));
45 if (!rs.is_reserved()) {
46 vm_exit_during_initialization("Could not reserve enough space for heap offset array");
47 }
48 if (!_vs.initialize(rs, 0)) {
49 vm_exit_during_initialization("Could not reserve enough space for heap offset array");
50 }
51
52 MemTracker::record_virtual_memory_type((address)rs.base(), mtGC);
53
54 _offset_array = (u_char*)_vs.low_boundary();
55 resize(init_word_size);
56 if (TraceBlockOffsetTable) {
57 gclog_or_tty->print_cr("G1BlockOffsetSharedArray::G1BlockOffsetSharedArray: ");
58 gclog_or_tty->print_cr(" "
59 " rs.base(): " INTPTR_FORMAT
60 " rs.size(): " INTPTR_FORMAT
61 " rs end(): " INTPTR_FORMAT,
62 rs.base(), rs.size(), rs.base() + rs.size());
63 gclog_or_tty->print_cr(" "
64 " _vs.low_boundary(): " INTPTR_FORMAT
65 " _vs.high_boundary(): " INTPTR_FORMAT,
66 _vs.low_boundary(),
67 _vs.high_boundary());
68 }
69 }
70
71 void G1BlockOffsetSharedArray::resize(size_t new_word_size) {
72 assert(new_word_size <= _reserved.word_size(), "Resize larger than reserved");
73 size_t new_size = compute_size(new_word_size);
74 size_t old_size = _vs.committed_size();
75 size_t delta;
76 char* high = _vs.high();
77 _end = _reserved.start() + new_word_size;
78 if (new_size > old_size) {
79 delta = ReservedSpace::page_align_size_up(new_size - old_size);
80 assert(delta > 0, "just checking");
81 if (!_vs.expand_by(delta)) {
82 // Do better than this for Merlin
83 vm_exit_out_of_memory(delta, OOM_MMAP_ERROR, "offset table expansion");
84 }
85 assert(_vs.high() == high + delta, "invalid expansion");
86 // Initialization of the contents is left to the
87 // G1BlockOffsetArray that uses it.
88 } else {
89 delta = ReservedSpace::page_align_size_down(old_size - new_size);
90 if (delta == 0) return;
91 _vs.shrink_by(delta);
92 assert(_vs.high() == high - delta, "invalid expansion");
93 }
94 }
95
96 bool G1BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const {
97 assert(p >= _reserved.start(), "just checking");
98 size_t delta = pointer_delta(p, _reserved.start());
99 return (delta & right_n_bits(LogN_words)) == (size_t)NoBits;
100 }
101
102 void G1BlockOffsetSharedArray::set_offset_array(HeapWord* left, HeapWord* right, u_char offset) {
103 check_index(index_for(right - 1), "right address out of range");
104 assert(left < right, "Heap addresses out of order");
105 size_t num_cards = pointer_delta(right, left) >> LogN_words;
106 if (UseMemSetInBOT) {
107 memset(&_offset_array[index_for(left)], offset, num_cards);
108 } else {
109 size_t i = index_for(left);
110 const size_t end = i + num_cards;
111 for (; i < end; i++) {
112 _offset_array[i] = offset;
113 }
114 }
115 }
116
117
118 //////////////////////////////////////////////////////////////////////
119 // G1BlockOffsetArray
120 //////////////////////////////////////////////////////////////////////
121
122 G1BlockOffsetArray::G1BlockOffsetArray(G1BlockOffsetSharedArray* array,
123 MemRegion mr, bool init_to_zero) :
124 G1BlockOffsetTable(mr.start(), mr.end()),
125 _unallocated_block(_bottom),
126 _array(array), _gsp(NULL),
127 _init_to_zero(init_to_zero) {
128 assert(_bottom <= _end, "arguments out of order");
129 if (!_init_to_zero) {
130 // initialize cards to point back to mr.start()
131 set_remainder_to_point_to_start(mr.start() + N_words, mr.end());
132 _array->set_offset_array(0, 0); // set first card to 0
133 }
134 }
135
136 void G1BlockOffsetArray::set_space(G1OffsetTableContigSpace* sp) {
137 _gsp = sp;
138 }
139
140 // The arguments follow the normal convention of denoting
141 // a right-open interval: [start, end)
142 void
143 G1BlockOffsetArray:: set_remainder_to_point_to_start(HeapWord* start, HeapWord* end) {
144
145 if (start >= end) {
146 // The start address is equal to the end address (or to
147 // the right of the end address) so there are not cards
148 // that need to be updated..
149 return;
150 }
151
152 // Write the backskip value for each region.
153 //
154 // offset
155 // card 2nd 3rd
156 // | +- 1st | |
157 // v v v v
158 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-
159 // |x|0|0|0|0|0|0|0|1|1|1|1|1|1| ... |1|1|1|1|2|2|2|2|2|2| ...
160 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-
161 // 11 19 75
162 // 12
163 //
164 // offset card is the card that points to the start of an object
165 // x - offset value of offset card
166 // 1st - start of first logarithmic region
167 // 0 corresponds to logarithmic value N_words + 0 and 2**(3 * 0) = 1
168 // 2nd - start of second logarithmic region
169 // 1 corresponds to logarithmic value N_words + 1 and 2**(3 * 1) = 8
170 // 3rd - start of third logarithmic region
171 // 2 corresponds to logarithmic value N_words + 2 and 2**(3 * 2) = 64
172 //
173 // integer below the block offset entry is an example of
174 // the index of the entry
175 //
176 // Given an address,
177 // Find the index for the address
178 // Find the block offset table entry
179 // Convert the entry to a back slide
180 // (e.g., with today's, offset = 0x81 =>
181 // back slip = 2**(3*(0x81 - N_words)) = 2**3) = 8
182 // Move back N (e.g., 8) entries and repeat with the
183 // value of the new entry
184 //
185 size_t start_card = _array->index_for(start);
186 size_t end_card = _array->index_for(end-1);
187 assert(start ==_array->address_for_index(start_card), "Precondition");
188 assert(end ==_array->address_for_index(end_card)+N_words, "Precondition");
189 set_remainder_to_point_to_start_incl(start_card, end_card); // closed interval
190 }
191
192 // Unlike the normal convention in this code, the argument here denotes
193 // a closed, inclusive interval: [start_card, end_card], cf set_remainder_to_point_to_start()
194 // above.
195 void
196 G1BlockOffsetArray::set_remainder_to_point_to_start_incl(size_t start_card, size_t end_card) {
197 if (start_card > end_card) {
198 return;
199 }
200 assert(start_card > _array->index_for(_bottom), "Cannot be first card");
201 assert(_array->offset_array(start_card-1) <= N_words,
202 "Offset card has an unexpected value");
203 size_t start_card_for_region = start_card;
204 u_char offset = max_jubyte;
205 for (int i = 0; i < BlockOffsetArray::N_powers; i++) {
206 // -1 so that the the card with the actual offset is counted. Another -1
207 // so that the reach ends in this region and not at the start
208 // of the next.
209 size_t reach = start_card - 1 + (BlockOffsetArray::power_to_cards_back(i+1) - 1);
210 offset = N_words + i;
211 if (reach >= end_card) {
212 _array->set_offset_array(start_card_for_region, end_card, offset);
213 start_card_for_region = reach + 1;
214 break;
215 }
216 _array->set_offset_array(start_card_for_region, reach, offset);
217 start_card_for_region = reach + 1;
218 }
219 assert(start_card_for_region > end_card, "Sanity check");
220 DEBUG_ONLY(check_all_cards(start_card, end_card);)
221 }
222
223 // The block [blk_start, blk_end) has been allocated;
224 // adjust the block offset table to represent this information;
225 // right-open interval: [blk_start, blk_end)
226 void
227 G1BlockOffsetArray::alloc_block(HeapWord* blk_start, HeapWord* blk_end) {
228 mark_block(blk_start, blk_end);
229 allocated(blk_start, blk_end);
230 }
231
232 // Adjust BOT to show that a previously whole block has been split
233 // into two.
234 void G1BlockOffsetArray::split_block(HeapWord* blk, size_t blk_size,
235 size_t left_blk_size) {
236 // Verify that the BOT shows [blk, blk + blk_size) to be one block.
237 verify_single_block(blk, blk_size);
238 // Update the BOT to indicate that [blk + left_blk_size, blk + blk_size)
239 // is one single block.
240 mark_block(blk + left_blk_size, blk + blk_size);
241 }
242
243
244 // Action_mark - update the BOT for the block [blk_start, blk_end).
245 // Current typical use is for splitting a block.
246 // Action_single - update the BOT for an allocation.
247 // Action_verify - BOT verification.
248 void G1BlockOffsetArray::do_block_internal(HeapWord* blk_start,
249 HeapWord* blk_end,
250 Action action) {
251 assert(Universe::heap()->is_in_reserved(blk_start),
252 "reference must be into the heap");
253 assert(Universe::heap()->is_in_reserved(blk_end-1),
254 "limit must be within the heap");
255 // This is optimized to make the test fast, assuming we only rarely
256 // cross boundaries.
257 uintptr_t end_ui = (uintptr_t)(blk_end - 1);
258 uintptr_t start_ui = (uintptr_t)blk_start;
259 // Calculate the last card boundary preceding end of blk
260 intptr_t boundary_before_end = (intptr_t)end_ui;
261 clear_bits(boundary_before_end, right_n_bits(LogN));
262 if (start_ui <= (uintptr_t)boundary_before_end) {
263 // blk starts at or crosses a boundary
264 // Calculate index of card on which blk begins
265 size_t start_index = _array->index_for(blk_start);
266 // Index of card on which blk ends
267 size_t end_index = _array->index_for(blk_end - 1);
268 // Start address of card on which blk begins
269 HeapWord* boundary = _array->address_for_index(start_index);
270 assert(boundary <= blk_start, "blk should start at or after boundary");
271 if (blk_start != boundary) {
272 // blk starts strictly after boundary
273 // adjust card boundary and start_index forward to next card
274 boundary += N_words;
275 start_index++;
276 }
277 assert(start_index <= end_index, "monotonicity of index_for()");
278 assert(boundary <= (HeapWord*)boundary_before_end, "tautology");
279 switch (action) {
280 case Action_mark: {
281 if (init_to_zero()) {
282 _array->set_offset_array(start_index, boundary, blk_start);
283 break;
284 } // Else fall through to the next case
285 }
286 case Action_single: {
287 _array->set_offset_array(start_index, boundary, blk_start);
288 // We have finished marking the "offset card". We need to now
289 // mark the subsequent cards that this blk spans.
290 if (start_index < end_index) {
291 HeapWord* rem_st = _array->address_for_index(start_index) + N_words;
292 HeapWord* rem_end = _array->address_for_index(end_index) + N_words;
293 set_remainder_to_point_to_start(rem_st, rem_end);
294 }
295 break;
296 }
297 case Action_check: {
298 _array->check_offset_array(start_index, boundary, blk_start);
299 // We have finished checking the "offset card". We need to now
300 // check the subsequent cards that this blk spans.
301 check_all_cards(start_index + 1, end_index);
302 break;
303 }
304 default:
305 ShouldNotReachHere();
306 }
307 }
308 }
309
310 // The card-interval [start_card, end_card] is a closed interval; this
311 // is an expensive check -- use with care and only under protection of
312 // suitable flag.
313 void G1BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const {
314
315 if (end_card < start_card) {
316 return;
317 }
318 guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card");
319 for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) {
320 u_char entry = _array->offset_array(c);
321 if (c - start_card > BlockOffsetArray::power_to_cards_back(1)) {
322 guarantee(entry > N_words,
323 err_msg("Should be in logarithmic region - "
324 "entry: %u, "
325 "_array->offset_array(c): %u, "
326 "N_words: %u",
327 (uint)entry, (uint)_array->offset_array(c), (uint)N_words));
328 }
329 size_t backskip = BlockOffsetArray::entry_to_cards_back(entry);
330 size_t landing_card = c - backskip;
331 guarantee(landing_card >= (start_card - 1), "Inv");
332 if (landing_card >= start_card) {
333 guarantee(_array->offset_array(landing_card) <= entry,
334 err_msg("Monotonicity - landing_card offset: %u, "
335 "entry: %u",
336 (uint)_array->offset_array(landing_card), (uint)entry));
337 } else {
338 guarantee(landing_card == start_card - 1, "Tautology");
339 // Note that N_words is the maximum offset value
340 guarantee(_array->offset_array(landing_card) <= N_words,
341 err_msg("landing card offset: %u, "
342 "N_words: %u",
343 (uint)_array->offset_array(landing_card), (uint)N_words));
344 }
345 }
346 }
347
348 // The range [blk_start, blk_end) represents a single contiguous block
349 // of storage; modify the block offset table to represent this
350 // information; Right-open interval: [blk_start, blk_end)
351 // NOTE: this method does _not_ adjust _unallocated_block.
352 void
353 G1BlockOffsetArray::single_block(HeapWord* blk_start, HeapWord* blk_end) {
354 do_block_internal(blk_start, blk_end, Action_single);
355 }
356
357 // Mark the BOT such that if [blk_start, blk_end) straddles a card
358 // boundary, the card following the first such boundary is marked
359 // with the appropriate offset.
360 // NOTE: this method does _not_ adjust _unallocated_block or
361 // any cards subsequent to the first one.
362 void
363 G1BlockOffsetArray::mark_block(HeapWord* blk_start, HeapWord* blk_end) {
364 do_block_internal(blk_start, blk_end, Action_mark);
365 }
366
367 HeapWord* G1BlockOffsetArray::block_start_unsafe(const void* addr) {
368 assert(_bottom <= addr && addr < _end,
369 "addr must be covered by this Array");
370 // Must read this exactly once because it can be modified by parallel
371 // allocation.
372 HeapWord* ub = _unallocated_block;
373 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
374 assert(ub < _end, "tautology (see above)");
375 return ub;
376 }
377 // Otherwise, find the block start using the table.
378 HeapWord* q = block_at_or_preceding(addr, false, 0);
379 return forward_to_block_containing_addr(q, addr);
380 }
381
382 // This duplicates a little code from the above: unavoidable.
383 HeapWord*
384 G1BlockOffsetArray::block_start_unsafe_const(const void* addr) const {
385 assert(_bottom <= addr && addr < _end,
386 "addr must be covered by this Array");
387 // Must read this exactly once because it can be modified by parallel
388 // allocation.
389 HeapWord* ub = _unallocated_block;
390 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
391 assert(ub < _end, "tautology (see above)");
392 return ub;
393 }
394 // Otherwise, find the block start using the table.
395 HeapWord* q = block_at_or_preceding(addr, false, 0);
396 HeapWord* n = q + block_size(q);
397 return forward_to_block_containing_addr_const(q, n, addr);
398 }
399
400
401 HeapWord*
402 G1BlockOffsetArray::forward_to_block_containing_addr_slow(HeapWord* q,
403 HeapWord* n,
404 const void* addr) {
405 // We're not in the normal case. We need to handle an important subcase
406 // here: LAB allocation. An allocation previously recorded in the
407 // offset table was actually a lab allocation, and was divided into
408 // several objects subsequently. Fix this situation as we answer the
409 // query, by updating entries as we cross them.
410
411 // If the fist object's end q is at the card boundary. Start refining
412 // with the corresponding card (the value of the entry will be basically
413 // set to 0). If the object crosses the boundary -- start from the next card.
414 size_t n_index = _array->index_for(n);
415 size_t next_index = _array->index_for(n) + !_array->is_card_boundary(n);
416 // Calculate a consistent next boundary. If "n" is not at the boundary
417 // already, step to the boundary.
418 HeapWord* next_boundary = _array->address_for_index(n_index) +
419 (n_index == next_index ? 0 : N_words);
420 assert(next_boundary <= _array->_end,
421 err_msg("next_boundary is beyond the end of the covered region "
422 " next_boundary " PTR_FORMAT " _array->_end " PTR_FORMAT,
423 next_boundary, _array->_end));
424 if (addr >= gsp()->top()) return gsp()->top();
425 while (next_boundary < addr) {
426 while (n <= next_boundary) {
427 q = n;
428 oop obj = oop(q);
429 if (obj->klass_or_null() == NULL) return q;
430 n += block_size(q);
431 }
432 assert(q <= next_boundary && n > next_boundary, "Consequence of loop");
433 // [q, n) is the block that crosses the boundary.
434 alloc_block_work2(&next_boundary, &next_index, q, n);
435 }
436 return forward_to_block_containing_addr_const(q, n, addr);
437 }
438
439 HeapWord* G1BlockOffsetArray::block_start_careful(const void* addr) const {
440 assert(_array->offset_array(0) == 0, "objects can't cross covered areas");
441
442 assert(_bottom <= addr && addr < _end,
443 "addr must be covered by this Array");
444 // Must read this exactly once because it can be modified by parallel
445 // allocation.
446 HeapWord* ub = _unallocated_block;
447 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
448 assert(ub < _end, "tautology (see above)");
449 return ub;
450 }
451
452 // Otherwise, find the block start using the table, but taking
453 // care (cf block_start_unsafe() above) not to parse any objects/blocks
454 // on the cards themselves.
455 size_t index = _array->index_for(addr);
456 assert(_array->address_for_index(index) == addr,
457 "arg should be start of card");
458
459 HeapWord* q = (HeapWord*)addr;
460 uint offset;
461 do {
462 offset = _array->offset_array(index--);
463 q -= offset;
464 } while (offset == N_words);
465 assert(q <= addr, "block start should be to left of arg");
466 return q;
467 }
468
469 // Note that the committed size of the covered space may have changed,
470 // so the table size might also wish to change.
471 void G1BlockOffsetArray::resize(size_t new_word_size) {
472 HeapWord* new_end = _bottom + new_word_size;
473 if (_end < new_end && !init_to_zero()) {
474 // verify that the old and new boundaries are also card boundaries
475 assert(_array->is_card_boundary(_end),
476 "_end not a card boundary");
477 assert(_array->is_card_boundary(new_end),
478 "new _end would not be a card boundary");
479 // set all the newly added cards
480 _array->set_offset_array(_end, new_end, N_words);
481 }
482 _end = new_end; // update _end
483 }
484
485 void G1BlockOffsetArray::set_region(MemRegion mr) {
486 _bottom = mr.start();
487 _end = mr.end();
488 }
489
490 //
491 // threshold_
492 // | _index_
493 // v v
494 // +-------+-------+-------+-------+-------+
495 // | i-1 | i | i+1 | i+2 | i+3 |
496 // +-------+-------+-------+-------+-------+
497 // ( ^ ]
498 // block-start
499 //
500 void G1BlockOffsetArray::alloc_block_work2(HeapWord** threshold_, size_t* index_,
501 HeapWord* blk_start, HeapWord* blk_end) {
502 // For efficiency, do copy-in/copy-out.
503 HeapWord* threshold = *threshold_;
504 size_t index = *index_;
505
506 assert(blk_start != NULL && blk_end > blk_start,
507 "phantom block");
508 assert(blk_end > threshold, "should be past threshold");
509 assert(blk_start <= threshold, "blk_start should be at or before threshold");
510 assert(pointer_delta(threshold, blk_start) <= N_words,
511 "offset should be <= BlockOffsetSharedArray::N");
512 assert(Universe::heap()->is_in_reserved(blk_start),
513 "reference must be into the heap");
514 assert(Universe::heap()->is_in_reserved(blk_end-1),
515 "limit must be within the heap");
516 assert(threshold == _array->_reserved.start() + index*N_words,
517 "index must agree with threshold");
518
519 DEBUG_ONLY(size_t orig_index = index;)
520
521 // Mark the card that holds the offset into the block. Note
522 // that _next_offset_index and _next_offset_threshold are not
523 // updated until the end of this method.
524 _array->set_offset_array(index, threshold, blk_start);
525
526 // We need to now mark the subsequent cards that this blk spans.
527
528 // Index of card on which blk ends.
529 size_t end_index = _array->index_for(blk_end - 1);
530
531 // Are there more cards left to be updated?
532 if (index + 1 <= end_index) {
533 HeapWord* rem_st = _array->address_for_index(index + 1);
534 // Calculate rem_end this way because end_index
535 // may be the last valid index in the covered region.
536 HeapWord* rem_end = _array->address_for_index(end_index) + N_words;
537 set_remainder_to_point_to_start(rem_st, rem_end);
538 }
539
540 index = end_index + 1;
541 // Calculate threshold_ this way because end_index
542 // may be the last valid index in the covered region.
543 threshold = _array->address_for_index(end_index) + N_words;
544 assert(threshold >= blk_end, "Incorrect offset threshold");
545
546 // index_ and threshold_ updated here.
547 *threshold_ = threshold;
548 *index_ = index;
549
550 #ifdef ASSERT
551 // The offset can be 0 if the block starts on a boundary. That
552 // is checked by an assertion above.
553 size_t start_index = _array->index_for(blk_start);
554 HeapWord* boundary = _array->address_for_index(start_index);
555 assert((_array->offset_array(orig_index) == 0 &&
556 blk_start == boundary) ||
557 (_array->offset_array(orig_index) > 0 &&
558 _array->offset_array(orig_index) <= N_words),
559 err_msg("offset array should have been set - "
560 "orig_index offset: %u, "
561 "blk_start: " PTR_FORMAT ", "
562 "boundary: " PTR_FORMAT,
563 (uint)_array->offset_array(orig_index),
564 blk_start, boundary));
565 for (size_t j = orig_index + 1; j <= end_index; j++) {
566 assert(_array->offset_array(j) > 0 &&
567 _array->offset_array(j) <=
568 (u_char) (N_words+BlockOffsetArray::N_powers-1),
569 err_msg("offset array should have been set - "
570 "%u not > 0 OR %u not <= %u",
571 (uint) _array->offset_array(j),
572 (uint) _array->offset_array(j),
573 (uint) (N_words+BlockOffsetArray::N_powers-1)));
574 }
575 #endif
576 }
577
578 bool
579 G1BlockOffsetArray::verify_for_object(HeapWord* obj_start,
580 size_t word_size) const {
581 size_t first_card = _array->index_for(obj_start);
582 size_t last_card = _array->index_for(obj_start + word_size - 1);
583 if (!_array->is_card_boundary(obj_start)) {
584 // If the object is not on a card boundary the BOT entry of the
585 // first card should point to another object so we should not
586 // check that one.
587 first_card += 1;
588 }
589 for (size_t card = first_card; card <= last_card; card += 1) {
590 HeapWord* card_addr = _array->address_for_index(card);
591 HeapWord* block_start = block_start_const(card_addr);
592 if (block_start != obj_start) {
593 gclog_or_tty->print_cr("block start: "PTR_FORMAT" is incorrect - "
594 "card index: "SIZE_FORMAT" "
595 "card addr: "PTR_FORMAT" BOT entry: %u "
596 "obj: "PTR_FORMAT" word size: "SIZE_FORMAT" "
597 "cards: ["SIZE_FORMAT","SIZE_FORMAT"]",
598 block_start, card, card_addr,
599 _array->offset_array(card),
600 obj_start, word_size, first_card, last_card);
601 return false;
602 }
603 }
604 return true;
605 }
606
607 #ifndef PRODUCT
608 void
609 G1BlockOffsetArray::print_on(outputStream* out) {
610 size_t from_index = _array->index_for(_bottom);
611 size_t to_index = _array->index_for(_end);
612 out->print_cr(">> BOT for area ["PTR_FORMAT","PTR_FORMAT") "
613 "cards ["SIZE_FORMAT","SIZE_FORMAT")",
614 _bottom, _end, from_index, to_index);
615 for (size_t i = from_index; i < to_index; ++i) {
616 out->print_cr(" entry "SIZE_FORMAT_W(8)" | "PTR_FORMAT" : %3u",
617 i, _array->address_for_index(i),
618 (uint) _array->offset_array(i));
619 }
620 }
621 #endif // !PRODUCT
622
623 //////////////////////////////////////////////////////////////////////
624 // G1BlockOffsetArrayContigSpace
625 //////////////////////////////////////////////////////////////////////
626
627 HeapWord*
628 G1BlockOffsetArrayContigSpace::block_start_unsafe(const void* addr) {
629 assert(_bottom <= addr && addr < _end,
630 "addr must be covered by this Array");
631 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
632 return forward_to_block_containing_addr(q, addr);
633 }
634
635 HeapWord*
636 G1BlockOffsetArrayContigSpace::
637 block_start_unsafe_const(const void* addr) const {
638 assert(_bottom <= addr && addr < _end,
639 "addr must be covered by this Array");
640 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
641 HeapWord* n = q + block_size(q);
642 return forward_to_block_containing_addr_const(q, n, addr);
643 }
644
645 G1BlockOffsetArrayContigSpace::
646 G1BlockOffsetArrayContigSpace(G1BlockOffsetSharedArray* array,
647 MemRegion mr) :
648 G1BlockOffsetArray(array, mr, true)
649 {
650 _next_offset_threshold = NULL;
651 _next_offset_index = 0;
652 }
653
654 HeapWord* G1BlockOffsetArrayContigSpace::initialize_threshold() {
655 assert(!Universe::heap()->is_in_reserved(_array->_offset_array),
656 "just checking");
657 _next_offset_index = _array->index_for(_bottom);
658 _next_offset_index++;
659 _next_offset_threshold =
660 _array->address_for_index(_next_offset_index);
661 return _next_offset_threshold;
662 }
663
664 void G1BlockOffsetArrayContigSpace::zero_bottom_entry() {
665 assert(!Universe::heap()->is_in_reserved(_array->_offset_array),
666 "just checking");
667 size_t bottom_index = _array->index_for(_bottom);
668 assert(_array->address_for_index(bottom_index) == _bottom,
669 "Precondition of call");
670 _array->set_offset_array(bottom_index, 0);
671 }
672
673 void
674 G1BlockOffsetArrayContigSpace::set_for_starts_humongous(HeapWord* new_top) {
675 assert(new_top <= _end, "_end should have already been updated");
676
677 // The first BOT entry should have offset 0.
678 zero_bottom_entry();
679 initialize_threshold();
680 alloc_block(_bottom, new_top);
681 }
682
683 #ifndef PRODUCT
684 void
685 G1BlockOffsetArrayContigSpace::print_on(outputStream* out) {
686 G1BlockOffsetArray::print_on(out);
687 out->print_cr(" next offset threshold: "PTR_FORMAT, _next_offset_threshold);
688 out->print_cr(" next offset index: "SIZE_FORMAT, _next_offset_index);
689 }
690 #endif // !PRODUCT