1 /*
2 * Copyright (c) 2001, 2012, 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 "memory/space.hpp"
28 #include "oops/oop.inline.hpp"
29 #include "runtime/java.hpp"
30 #include "services/memTracker.hpp"
31
32 //////////////////////////////////////////////////////////////////////
33 // G1BlockOffsetSharedArray
34 //////////////////////////////////////////////////////////////////////
35
36 G1BlockOffsetSharedArray::G1BlockOffsetSharedArray(MemRegion reserved,
37 size_t init_word_size) :
38 _reserved(reserved), _end(NULL)
39 {
40 size_t size = compute_size(reserved.word_size());
41 ReservedSpace rs(ReservedSpace::allocation_align_size_up(size));
42 if (!rs.is_reserved()) {
43 vm_exit_during_initialization("Could not reserve enough space for heap offset array");
44 }
45 if (!_vs.initialize(rs, 0)) {
46 vm_exit_during_initialization("Could not reserve enough space for heap offset array");
47 }
48
49 MemTracker::record_virtual_memory_type((address)rs.base(), mtGC);
50
51 _offset_array = (u_char*)_vs.low_boundary();
52 resize(init_word_size);
53 if (TraceBlockOffsetTable) {
54 gclog_or_tty->print_cr("G1BlockOffsetSharedArray::G1BlockOffsetSharedArray: ");
55 gclog_or_tty->print_cr(" "
56 " rs.base(): " INTPTR_FORMAT
57 " rs.size(): " INTPTR_FORMAT
58 " rs end(): " INTPTR_FORMAT,
59 rs.base(), rs.size(), rs.base() + rs.size());
60 gclog_or_tty->print_cr(" "
61 " _vs.low_boundary(): " INTPTR_FORMAT
62 " _vs.high_boundary(): " INTPTR_FORMAT,
63 _vs.low_boundary(),
64 _vs.high_boundary());
65 }
66 }
67
68 void G1BlockOffsetSharedArray::resize(size_t new_word_size) {
69 assert(new_word_size <= _reserved.word_size(), "Resize larger than reserved");
70 size_t new_size = compute_size(new_word_size);
71 size_t old_size = _vs.committed_size();
72 size_t delta;
73 char* high = _vs.high();
74 _end = _reserved.start() + new_word_size;
75 if (new_size > old_size) {
76 delta = ReservedSpace::page_align_size_up(new_size - old_size);
77 assert(delta > 0, "just checking");
78 if (!_vs.expand_by(delta)) {
79 // Do better than this for Merlin
80 vm_exit_out_of_memory(delta, OOM_MMAP_ERROR, "offset table expansion");
81 }
82 assert(_vs.high() == high + delta, "invalid expansion");
83 // Initialization of the contents is left to the
84 // G1BlockOffsetArray that uses it.
85 } else {
86 delta = ReservedSpace::page_align_size_down(old_size - new_size);
87 if (delta == 0) return;
88 _vs.shrink_by(delta);
89 assert(_vs.high() == high - delta, "invalid expansion");
90 }
91 }
92
93 bool G1BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const {
94 assert(p >= _reserved.start(), "just checking");
95 size_t delta = pointer_delta(p, _reserved.start());
96 return (delta & right_n_bits(LogN_words)) == (size_t)NoBits;
97 }
98
99
100 //////////////////////////////////////////////////////////////////////
101 // G1BlockOffsetArray
102 //////////////////////////////////////////////////////////////////////
103
104 G1BlockOffsetArray::G1BlockOffsetArray(G1BlockOffsetSharedArray* array,
105 MemRegion mr, bool init_to_zero) :
106 G1BlockOffsetTable(mr.start(), mr.end()),
107 _unallocated_block(_bottom),
108 _array(array), _csp(NULL),
109 _init_to_zero(init_to_zero) {
110 assert(_bottom <= _end, "arguments out of order");
111 if (!_init_to_zero) {
112 // initialize cards to point back to mr.start()
113 set_remainder_to_point_to_start(mr.start() + N_words, mr.end());
114 _array->set_offset_array(0, 0); // set first card to 0
115 }
116 }
117
118 void G1BlockOffsetArray::set_space(Space* sp) {
119 _sp = sp;
120 _csp = sp->toContiguousSpace();
121 }
122
123 // The arguments follow the normal convention of denoting
124 // a right-open interval: [start, end)
125 void
126 G1BlockOffsetArray:: set_remainder_to_point_to_start(HeapWord* start, HeapWord* end) {
127
128 if (start >= end) {
129 // The start address is equal to the end address (or to
130 // the right of the end address) so there are not cards
131 // that need to be updated..
132 return;
133 }
134
135 // Write the backskip value for each region.
136 //
137 // offset
138 // card 2nd 3rd
139 // | +- 1st | |
140 // v v v v
141 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-
142 // |x|0|0|0|0|0|0|0|1|1|1|1|1|1| ... |1|1|1|1|2|2|2|2|2|2| ...
143 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-
144 // 11 19 75
145 // 12
146 //
147 // offset card is the card that points to the start of an object
148 // x - offset value of offset card
149 // 1st - start of first logarithmic region
150 // 0 corresponds to logarithmic value N_words + 0 and 2**(3 * 0) = 1
151 // 2nd - start of second logarithmic region
152 // 1 corresponds to logarithmic value N_words + 1 and 2**(3 * 1) = 8
153 // 3rd - start of third logarithmic region
154 // 2 corresponds to logarithmic value N_words + 2 and 2**(3 * 2) = 64
155 //
156 // integer below the block offset entry is an example of
157 // the index of the entry
158 //
159 // Given an address,
160 // Find the index for the address
161 // Find the block offset table entry
162 // Convert the entry to a back slide
163 // (e.g., with today's, offset = 0x81 =>
164 // back slip = 2**(3*(0x81 - N_words)) = 2**3) = 8
165 // Move back N (e.g., 8) entries and repeat with the
166 // value of the new entry
167 //
168 size_t start_card = _array->index_for(start);
169 size_t end_card = _array->index_for(end-1);
170 assert(start ==_array->address_for_index(start_card), "Precondition");
171 assert(end ==_array->address_for_index(end_card)+N_words, "Precondition");
172 set_remainder_to_point_to_start_incl(start_card, end_card); // closed interval
173 }
174
175 // Unlike the normal convention in this code, the argument here denotes
176 // a closed, inclusive interval: [start_card, end_card], cf set_remainder_to_point_to_start()
177 // above.
178 void
179 G1BlockOffsetArray::set_remainder_to_point_to_start_incl(size_t start_card, size_t end_card) {
180 if (start_card > end_card) {
181 return;
182 }
183 assert(start_card > _array->index_for(_bottom), "Cannot be first card");
184 assert(_array->offset_array(start_card-1) <= N_words,
185 "Offset card has an unexpected value");
186 size_t start_card_for_region = start_card;
187 u_char offset = max_jubyte;
188 for (int i = 0; i < BlockOffsetArray::N_powers; i++) {
189 // -1 so that the the card with the actual offset is counted. Another -1
190 // so that the reach ends in this region and not at the start
191 // of the next.
192 size_t reach = start_card - 1 + (BlockOffsetArray::power_to_cards_back(i+1) - 1);
193 offset = N_words + i;
194 if (reach >= end_card) {
195 _array->set_offset_array(start_card_for_region, end_card, offset);
196 start_card_for_region = reach + 1;
197 break;
198 }
199 _array->set_offset_array(start_card_for_region, reach, offset);
200 start_card_for_region = reach + 1;
201 }
202 assert(start_card_for_region > end_card, "Sanity check");
203 DEBUG_ONLY(check_all_cards(start_card, end_card);)
204 }
205
206 // The block [blk_start, blk_end) has been allocated;
207 // adjust the block offset table to represent this information;
208 // right-open interval: [blk_start, blk_end)
209 void
210 G1BlockOffsetArray::alloc_block(HeapWord* blk_start, HeapWord* blk_end) {
211 mark_block(blk_start, blk_end);
212 allocated(blk_start, blk_end);
213 }
214
215 // Adjust BOT to show that a previously whole block has been split
216 // into two.
217 void G1BlockOffsetArray::split_block(HeapWord* blk, size_t blk_size,
218 size_t left_blk_size) {
219 // Verify that the BOT shows [blk, blk + blk_size) to be one block.
220 verify_single_block(blk, blk_size);
221 // Update the BOT to indicate that [blk + left_blk_size, blk + blk_size)
222 // is one single block.
223 mark_block(blk + left_blk_size, blk + blk_size);
224 }
225
226
227 // Action_mark - update the BOT for the block [blk_start, blk_end).
228 // Current typical use is for splitting a block.
229 // Action_single - update the BOT for an allocation.
230 // Action_verify - BOT verification.
231 void G1BlockOffsetArray::do_block_internal(HeapWord* blk_start,
232 HeapWord* blk_end,
233 Action action) {
234 assert(Universe::heap()->is_in_reserved(blk_start),
235 "reference must be into the heap");
236 assert(Universe::heap()->is_in_reserved(blk_end-1),
237 "limit must be within the heap");
238 // This is optimized to make the test fast, assuming we only rarely
239 // cross boundaries.
240 uintptr_t end_ui = (uintptr_t)(blk_end - 1);
241 uintptr_t start_ui = (uintptr_t)blk_start;
242 // Calculate the last card boundary preceding end of blk
243 intptr_t boundary_before_end = (intptr_t)end_ui;
244 clear_bits(boundary_before_end, right_n_bits(LogN));
245 if (start_ui <= (uintptr_t)boundary_before_end) {
246 // blk starts at or crosses a boundary
247 // Calculate index of card on which blk begins
248 size_t start_index = _array->index_for(blk_start);
249 // Index of card on which blk ends
250 size_t end_index = _array->index_for(blk_end - 1);
251 // Start address of card on which blk begins
252 HeapWord* boundary = _array->address_for_index(start_index);
253 assert(boundary <= blk_start, "blk should start at or after boundary");
254 if (blk_start != boundary) {
255 // blk starts strictly after boundary
256 // adjust card boundary and start_index forward to next card
257 boundary += N_words;
258 start_index++;
259 }
260 assert(start_index <= end_index, "monotonicity of index_for()");
261 assert(boundary <= (HeapWord*)boundary_before_end, "tautology");
262 switch (action) {
263 case Action_mark: {
264 if (init_to_zero()) {
265 _array->set_offset_array(start_index, boundary, blk_start);
266 break;
267 } // Else fall through to the next case
268 }
269 case Action_single: {
270 _array->set_offset_array(start_index, boundary, blk_start);
271 // We have finished marking the "offset card". We need to now
272 // mark the subsequent cards that this blk spans.
273 if (start_index < end_index) {
274 HeapWord* rem_st = _array->address_for_index(start_index) + N_words;
275 HeapWord* rem_end = _array->address_for_index(end_index) + N_words;
276 set_remainder_to_point_to_start(rem_st, rem_end);
277 }
278 break;
279 }
280 case Action_check: {
281 _array->check_offset_array(start_index, boundary, blk_start);
282 // We have finished checking the "offset card". We need to now
283 // check the subsequent cards that this blk spans.
284 check_all_cards(start_index + 1, end_index);
285 break;
286 }
287 default:
288 ShouldNotReachHere();
289 }
290 }
291 }
292
293 // The card-interval [start_card, end_card] is a closed interval; this
294 // is an expensive check -- use with care and only under protection of
295 // suitable flag.
296 void G1BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const {
297
298 if (end_card < start_card) {
299 return;
300 }
301 guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card");
302 for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) {
303 u_char entry = _array->offset_array(c);
304 if (c - start_card > BlockOffsetArray::power_to_cards_back(1)) {
305 guarantee(entry > N_words,
306 err_msg("Should be in logarithmic region - "
307 "entry: " UINT32_FORMAT ", "
308 "_array->offset_array(c): " UINT32_FORMAT ", "
309 "N_words: " UINT32_FORMAT,
310 entry, _array->offset_array(c), N_words));
311 }
312 size_t backskip = BlockOffsetArray::entry_to_cards_back(entry);
313 size_t landing_card = c - backskip;
314 guarantee(landing_card >= (start_card - 1), "Inv");
315 if (landing_card >= start_card) {
316 guarantee(_array->offset_array(landing_card) <= entry,
317 err_msg("Monotonicity - landing_card offset: " UINT32_FORMAT ", "
318 "entry: " UINT32_FORMAT,
319 _array->offset_array(landing_card), entry));
320 } else {
321 guarantee(landing_card == start_card - 1, "Tautology");
322 // Note that N_words is the maximum offset value
323 guarantee(_array->offset_array(landing_card) <= N_words,
324 err_msg("landing card offset: " UINT32_FORMAT ", "
325 "N_words: " UINT32_FORMAT,
326 _array->offset_array(landing_card), N_words));
327 }
328 }
329 }
330
331 // The range [blk_start, blk_end) represents a single contiguous block
332 // of storage; modify the block offset table to represent this
333 // information; Right-open interval: [blk_start, blk_end)
334 // NOTE: this method does _not_ adjust _unallocated_block.
335 void
336 G1BlockOffsetArray::single_block(HeapWord* blk_start, HeapWord* blk_end) {
337 do_block_internal(blk_start, blk_end, Action_single);
338 }
339
340 // Mark the BOT such that if [blk_start, blk_end) straddles a card
341 // boundary, the card following the first such boundary is marked
342 // with the appropriate offset.
343 // NOTE: this method does _not_ adjust _unallocated_block or
344 // any cards subsequent to the first one.
345 void
346 G1BlockOffsetArray::mark_block(HeapWord* blk_start, HeapWord* blk_end) {
347 do_block_internal(blk_start, blk_end, Action_mark);
348 }
349
350 HeapWord* G1BlockOffsetArray::block_start_unsafe(const void* addr) {
351 assert(_bottom <= addr && addr < _end,
352 "addr must be covered by this Array");
353 // Must read this exactly once because it can be modified by parallel
354 // allocation.
355 HeapWord* ub = _unallocated_block;
356 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
357 assert(ub < _end, "tautology (see above)");
358 return ub;
359 }
360 // Otherwise, find the block start using the table.
361 HeapWord* q = block_at_or_preceding(addr, false, 0);
362 return forward_to_block_containing_addr(q, addr);
363 }
364
365 // This duplicates a little code from the above: unavoidable.
366 HeapWord*
367 G1BlockOffsetArray::block_start_unsafe_const(const void* addr) const {
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 HeapWord* n = q + _sp->block_size(q);
380 return forward_to_block_containing_addr_const(q, n, addr);
381 }
382
383
384 HeapWord*
385 G1BlockOffsetArray::forward_to_block_containing_addr_slow(HeapWord* q,
386 HeapWord* n,
387 const void* addr) {
388 // We're not in the normal case. We need to handle an important subcase
389 // here: LAB allocation. An allocation previously recorded in the
390 // offset table was actually a lab allocation, and was divided into
391 // several objects subsequently. Fix this situation as we answer the
392 // query, by updating entries as we cross them.
393
394 // If the fist object's end q is at the card boundary. Start refining
395 // with the corresponding card (the value of the entry will be basically
396 // set to 0). If the object crosses the boundary -- start from the next card.
397 size_t n_index = _array->index_for(n);
398 size_t next_index = _array->index_for(n) + !_array->is_card_boundary(n);
399 // Calculate a consistent next boundary. If "n" is not at the boundary
400 // already, step to the boundary.
401 HeapWord* next_boundary = _array->address_for_index(n_index) +
402 (n_index == next_index ? 0 : N_words);
403 assert(next_boundary <= _array->_end,
404 err_msg("next_boundary is beyond the end of the covered region "
405 " next_boundary " PTR_FORMAT " _array->_end " PTR_FORMAT,
406 next_boundary, _array->_end));
407 if (csp() != NULL) {
408 if (addr >= csp()->top()) return csp()->top();
409 while (next_boundary < addr) {
410 while (n <= next_boundary) {
411 q = n;
412 oop obj = oop(q);
413 if (obj->klass_or_null() == NULL) return q;
414 n += obj->size();
415 }
416 assert(q <= next_boundary && n > next_boundary, "Consequence of loop");
417 // [q, n) is the block that crosses the boundary.
418 alloc_block_work2(&next_boundary, &next_index, q, n);
419 }
420 } else {
421 while (next_boundary < addr) {
422 while (n <= next_boundary) {
423 q = n;
424 oop obj = oop(q);
425 if (obj->klass_or_null() == NULL) return q;
426 n += _sp->block_size(q);
427 }
428 assert(q <= next_boundary && n > next_boundary, "Consequence of loop");
429 // [q, n) is the block that crosses the boundary.
430 alloc_block_work2(&next_boundary, &next_index, q, n);
431 }
432 }
433 return forward_to_block_containing_addr_const(q, n, addr);
434 }
435
436 HeapWord* G1BlockOffsetArray::block_start_careful(const void* addr) const {
437 assert(_array->offset_array(0) == 0, "objects can't cross covered areas");
438
439 assert(_bottom <= addr && addr < _end,
440 "addr must be covered by this Array");
441 // Must read this exactly once because it can be modified by parallel
442 // allocation.
443 HeapWord* ub = _unallocated_block;
444 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
445 assert(ub < _end, "tautology (see above)");
446 return ub;
447 }
448
449 // Otherwise, find the block start using the table, but taking
450 // care (cf block_start_unsafe() above) not to parse any objects/blocks
451 // on the cards themsleves.
452 size_t index = _array->index_for(addr);
453 assert(_array->address_for_index(index) == addr,
454 "arg should be start of card");
455
456 HeapWord* q = (HeapWord*)addr;
457 uint offset;
458 do {
459 offset = _array->offset_array(index--);
460 q -= offset;
461 } while (offset == N_words);
462 assert(q <= addr, "block start should be to left of arg");
463 return q;
464 }
465
466 // Note that the committed size of the covered space may have changed,
467 // so the table size might also wish to change.
468 void G1BlockOffsetArray::resize(size_t new_word_size) {
469 HeapWord* new_end = _bottom + new_word_size;
470 if (_end < new_end && !init_to_zero()) {
471 // verify that the old and new boundaries are also card boundaries
472 assert(_array->is_card_boundary(_end),
473 "_end not a card boundary");
474 assert(_array->is_card_boundary(new_end),
475 "new _end would not be a card boundary");
476 // set all the newly added cards
477 _array->set_offset_array(_end, new_end, N_words);
478 }
479 _end = new_end; // update _end
480 }
481
482 void G1BlockOffsetArray::set_region(MemRegion mr) {
483 _bottom = mr.start();
484 _end = mr.end();
485 }
486
487 //
488 // threshold_
489 // | _index_
490 // v v
491 // +-------+-------+-------+-------+-------+
492 // | i-1 | i | i+1 | i+2 | i+3 |
493 // +-------+-------+-------+-------+-------+
494 // ( ^ ]
495 // block-start
496 //
497 void G1BlockOffsetArray::alloc_block_work2(HeapWord** threshold_, size_t* index_,
498 HeapWord* blk_start, HeapWord* blk_end) {
499 // For efficiency, do copy-in/copy-out.
500 HeapWord* threshold = *threshold_;
501 size_t index = *index_;
502
503 assert(blk_start != NULL && blk_end > blk_start,
504 "phantom block");
505 assert(blk_end > threshold, "should be past threshold");
506 assert(blk_start <= threshold, "blk_start should be at or before threshold");
507 assert(pointer_delta(threshold, blk_start) <= N_words,
508 "offset should be <= BlockOffsetSharedArray::N");
509 assert(Universe::heap()->is_in_reserved(blk_start),
510 "reference must be into the heap");
511 assert(Universe::heap()->is_in_reserved(blk_end-1),
512 "limit must be within the heap");
513 assert(threshold == _array->_reserved.start() + index*N_words,
514 "index must agree with threshold");
515
516 DEBUG_ONLY(size_t orig_index = index;)
517
518 // Mark the card that holds the offset into the block. Note
519 // that _next_offset_index and _next_offset_threshold are not
520 // updated until the end of this method.
521 _array->set_offset_array(index, threshold, blk_start);
522
523 // We need to now mark the subsequent cards that this blk spans.
524
525 // Index of card on which blk ends.
526 size_t end_index = _array->index_for(blk_end - 1);
527
528 // Are there more cards left to be updated?
529 if (index + 1 <= end_index) {
530 HeapWord* rem_st = _array->address_for_index(index + 1);
531 // Calculate rem_end this way because end_index
532 // may be the last valid index in the covered region.
533 HeapWord* rem_end = _array->address_for_index(end_index) + N_words;
534 set_remainder_to_point_to_start(rem_st, rem_end);
535 }
536
537 index = end_index + 1;
538 // Calculate threshold_ this way because end_index
539 // may be the last valid index in the covered region.
540 threshold = _array->address_for_index(end_index) + N_words;
541 assert(threshold >= blk_end, "Incorrect offset threshold");
542
543 // index_ and threshold_ updated here.
544 *threshold_ = threshold;
545 *index_ = index;
546
547 #ifdef ASSERT
548 // The offset can be 0 if the block starts on a boundary. That
549 // is checked by an assertion above.
550 size_t start_index = _array->index_for(blk_start);
551 HeapWord* boundary = _array->address_for_index(start_index);
552 assert((_array->offset_array(orig_index) == 0 &&
553 blk_start == boundary) ||
554 (_array->offset_array(orig_index) > 0 &&
555 _array->offset_array(orig_index) <= N_words),
556 err_msg("offset array should have been set - "
557 "orig_index offset: " UINT32_FORMAT ", "
558 "blk_start: " PTR_FORMAT ", "
559 "boundary: " PTR_FORMAT,
560 _array->offset_array(orig_index),
561 blk_start, boundary));
562 for (size_t j = orig_index + 1; j <= end_index; j++) {
563 assert(_array->offset_array(j) > 0 &&
564 _array->offset_array(j) <=
565 (u_char) (N_words+BlockOffsetArray::N_powers-1),
566 err_msg("offset array should have been set - "
567 UINT32_FORMAT " not > 0 OR "
568 UINT32_FORMAT " not <= " UINT32_FORMAT,
569 _array->offset_array(j),
570 _array->offset_array(j),
571 (u_char) (N_words+BlockOffsetArray::N_powers-1)));
572 }
573 #endif
574 }
575
576 bool
577 G1BlockOffsetArray::verify_for_object(HeapWord* obj_start,
578 size_t word_size) const {
579 size_t first_card = _array->index_for(obj_start);
580 size_t last_card = _array->index_for(obj_start + word_size - 1);
581 if (!_array->is_card_boundary(obj_start)) {
582 // If the object is not on a card boundary the BOT entry of the
583 // first card should point to another object so we should not
584 // check that one.
585 first_card += 1;
586 }
587 for (size_t card = first_card; card <= last_card; card += 1) {
588 HeapWord* card_addr = _array->address_for_index(card);
589 HeapWord* block_start = block_start_const(card_addr);
590 if (block_start != obj_start) {
591 gclog_or_tty->print_cr("block start: "PTR_FORMAT" is incorrect - "
592 "card index: "SIZE_FORMAT" "
593 "card addr: "PTR_FORMAT" BOT entry: %u "
594 "obj: "PTR_FORMAT" word size: "SIZE_FORMAT" "
595 "cards: ["SIZE_FORMAT","SIZE_FORMAT"]",
596 block_start, card, card_addr,
597 _array->offset_array(card),
598 obj_start, word_size, first_card, last_card);
599 return false;
600 }
601 }
602 return true;
603 }
604
605 #ifndef PRODUCT
606 void
607 G1BlockOffsetArray::print_on(outputStream* out) {
608 size_t from_index = _array->index_for(_bottom);
609 size_t to_index = _array->index_for(_end);
610 out->print_cr(">> BOT for area ["PTR_FORMAT","PTR_FORMAT") "
611 "cards ["SIZE_FORMAT","SIZE_FORMAT")",
612 _bottom, _end, from_index, to_index);
613 for (size_t i = from_index; i < to_index; ++i) {
614 out->print_cr(" entry "SIZE_FORMAT_W(8)" | "PTR_FORMAT" : %3u",
615 i, _array->address_for_index(i),
616 (uint) _array->offset_array(i));
617 }
618 }
619 #endif // !PRODUCT
620
621 //////////////////////////////////////////////////////////////////////
622 // G1BlockOffsetArrayContigSpace
623 //////////////////////////////////////////////////////////////////////
624
625 HeapWord*
626 G1BlockOffsetArrayContigSpace::block_start_unsafe(const void* addr) {
627 assert(_bottom <= addr && addr < _end,
628 "addr must be covered by this Array");
629 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
630 return forward_to_block_containing_addr(q, addr);
631 }
632
633 HeapWord*
634 G1BlockOffsetArrayContigSpace::
635 block_start_unsafe_const(const void* addr) const {
636 assert(_bottom <= addr && addr < _end,
637 "addr must be covered by this Array");
638 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
639 HeapWord* n = q + _sp->block_size(q);
640 return forward_to_block_containing_addr_const(q, n, addr);
641 }
642
643 G1BlockOffsetArrayContigSpace::
644 G1BlockOffsetArrayContigSpace(G1BlockOffsetSharedArray* array,
645 MemRegion mr) :
646 G1BlockOffsetArray(array, mr, true)
647 {
648 _next_offset_threshold = NULL;
649 _next_offset_index = 0;
650 }
651
652 HeapWord* G1BlockOffsetArrayContigSpace::initialize_threshold() {
653 assert(!Universe::heap()->is_in_reserved(_array->_offset_array),
654 "just checking");
655 _next_offset_index = _array->index_for(_bottom);
656 _next_offset_index++;
657 _next_offset_threshold =
658 _array->address_for_index(_next_offset_index);
659 return _next_offset_threshold;
660 }
661
662 void G1BlockOffsetArrayContigSpace::zero_bottom_entry() {
663 assert(!Universe::heap()->is_in_reserved(_array->_offset_array),
664 "just checking");
665 size_t bottom_index = _array->index_for(_bottom);
666 assert(_array->address_for_index(bottom_index) == _bottom,
667 "Precondition of call");
668 _array->set_offset_array(bottom_index, 0);
669 }
670
671 void
672 G1BlockOffsetArrayContigSpace::set_for_starts_humongous(HeapWord* new_top) {
673 assert(new_top <= _end, "_end should have already been updated");
674
675 // The first BOT entry should have offset 0.
676 zero_bottom_entry();
677 initialize_threshold();
678 alloc_block(_bottom, new_top);
679 }
680
681 #ifndef PRODUCT
682 void
683 G1BlockOffsetArrayContigSpace::print_on(outputStream* out) {
684 G1BlockOffsetArray::print_on(out);
685 out->print_cr(" next offset threshold: "PTR_FORMAT, _next_offset_threshold);
686 out->print_cr(" next offset index: "SIZE_FORMAT, _next_offset_index);
687 }
688 #endif // !PRODUCT