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