Tue, 10 May 2011 00:33:21 -0700
6883834: ParNew: assert(!_g->to()->is_in_reserved(obj),"Scanning field twice?") with LargeObjects tests
Summary: Fixed process_chunk_boundaries(), used for parallel card scanning when using ParNew/CMS, so as to prevent double-scanning, or worse, non-scanning of imprecisely marked objects exceeding parallel chunk size. Made some sizing parameters for parallel card scanning diagnostic, disabled ParallelGCRetainPLAB, and elaborated and clarified some comments.
Reviewed-by: stefank, johnc
1 /*
2 * Copyright (c) 2000, 2011, 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.
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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).
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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.
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23 */
25 #include "precompiled.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "memory/cardTableModRefBS.hpp"
28 #include "memory/cardTableRS.hpp"
29 #include "memory/sharedHeap.hpp"
30 #include "memory/space.hpp"
31 #include "memory/space.inline.hpp"
32 #include "memory/universe.hpp"
33 #include "runtime/java.hpp"
34 #include "runtime/mutexLocker.hpp"
35 #include "runtime/virtualspace.hpp"
36 #ifdef COMPILER1
37 #include "c1/c1_LIR.hpp"
38 #include "c1/c1_LIRGenerator.hpp"
39 #endif
41 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
42 // enumerate ref fields that have been modified (since the last
43 // enumeration.)
45 size_t CardTableModRefBS::cards_required(size_t covered_words)
46 {
47 // Add one for a guard card, used to detect errors.
48 const size_t words = align_size_up(covered_words, card_size_in_words);
49 return words / card_size_in_words + 1;
50 }
52 size_t CardTableModRefBS::compute_byte_map_size()
53 {
54 assert(_guard_index == cards_required(_whole_heap.word_size()) - 1,
55 "unitialized, check declaration order");
56 assert(_page_size != 0, "unitialized, check declaration order");
57 const size_t granularity = os::vm_allocation_granularity();
58 return align_size_up(_guard_index + 1, MAX2(_page_size, granularity));
59 }
61 CardTableModRefBS::CardTableModRefBS(MemRegion whole_heap,
62 int max_covered_regions):
63 ModRefBarrierSet(max_covered_regions),
64 _whole_heap(whole_heap),
65 _guard_index(cards_required(whole_heap.word_size()) - 1),
66 _last_valid_index(_guard_index - 1),
67 _page_size(os::vm_page_size()),
68 _byte_map_size(compute_byte_map_size())
69 {
70 _kind = BarrierSet::CardTableModRef;
72 HeapWord* low_bound = _whole_heap.start();
73 HeapWord* high_bound = _whole_heap.end();
74 assert((uintptr_t(low_bound) & (card_size - 1)) == 0, "heap must start at card boundary");
75 assert((uintptr_t(high_bound) & (card_size - 1)) == 0, "heap must end at card boundary");
77 assert(card_size <= 512, "card_size must be less than 512"); // why?
79 _covered = new MemRegion[max_covered_regions];
80 _committed = new MemRegion[max_covered_regions];
81 if (_covered == NULL || _committed == NULL)
82 vm_exit_during_initialization("couldn't alloc card table covered region set.");
83 int i;
84 for (i = 0; i < max_covered_regions; i++) {
85 _covered[i].set_word_size(0);
86 _committed[i].set_word_size(0);
87 }
88 _cur_covered_regions = 0;
90 const size_t rs_align = _page_size == (size_t) os::vm_page_size() ? 0 :
91 MAX2(_page_size, (size_t) os::vm_allocation_granularity());
92 ReservedSpace heap_rs(_byte_map_size, rs_align, false);
93 os::trace_page_sizes("card table", _guard_index + 1, _guard_index + 1,
94 _page_size, heap_rs.base(), heap_rs.size());
95 if (!heap_rs.is_reserved()) {
96 vm_exit_during_initialization("Could not reserve enough space for the "
97 "card marking array");
98 }
100 // The assember store_check code will do an unsigned shift of the oop,
101 // then add it to byte_map_base, i.e.
102 //
103 // _byte_map = byte_map_base + (uintptr_t(low_bound) >> card_shift)
104 _byte_map = (jbyte*) heap_rs.base();
105 byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
106 assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map");
107 assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map");
109 jbyte* guard_card = &_byte_map[_guard_index];
110 uintptr_t guard_page = align_size_down((uintptr_t)guard_card, _page_size);
111 _guard_region = MemRegion((HeapWord*)guard_page, _page_size);
112 if (!os::commit_memory((char*)guard_page, _page_size, _page_size)) {
113 // Do better than this for Merlin
114 vm_exit_out_of_memory(_page_size, "card table last card");
115 }
116 *guard_card = last_card;
118 _lowest_non_clean =
119 NEW_C_HEAP_ARRAY(CardArr, max_covered_regions);
120 _lowest_non_clean_chunk_size =
121 NEW_C_HEAP_ARRAY(size_t, max_covered_regions);
122 _lowest_non_clean_base_chunk_index =
123 NEW_C_HEAP_ARRAY(uintptr_t, max_covered_regions);
124 _last_LNC_resizing_collection =
125 NEW_C_HEAP_ARRAY(int, max_covered_regions);
126 if (_lowest_non_clean == NULL
127 || _lowest_non_clean_chunk_size == NULL
128 || _lowest_non_clean_base_chunk_index == NULL
129 || _last_LNC_resizing_collection == NULL)
130 vm_exit_during_initialization("couldn't allocate an LNC array.");
131 for (i = 0; i < max_covered_regions; i++) {
132 _lowest_non_clean[i] = NULL;
133 _lowest_non_clean_chunk_size[i] = 0;
134 _last_LNC_resizing_collection[i] = -1;
135 }
137 if (TraceCardTableModRefBS) {
138 gclog_or_tty->print_cr("CardTableModRefBS::CardTableModRefBS: ");
139 gclog_or_tty->print_cr(" "
140 " &_byte_map[0]: " INTPTR_FORMAT
141 " &_byte_map[_last_valid_index]: " INTPTR_FORMAT,
142 &_byte_map[0],
143 &_byte_map[_last_valid_index]);
144 gclog_or_tty->print_cr(" "
145 " byte_map_base: " INTPTR_FORMAT,
146 byte_map_base);
147 }
148 }
150 int CardTableModRefBS::find_covering_region_by_base(HeapWord* base) {
151 int i;
152 for (i = 0; i < _cur_covered_regions; i++) {
153 if (_covered[i].start() == base) return i;
154 if (_covered[i].start() > base) break;
155 }
156 // If we didn't find it, create a new one.
157 assert(_cur_covered_regions < _max_covered_regions,
158 "too many covered regions");
159 // Move the ones above up, to maintain sorted order.
160 for (int j = _cur_covered_regions; j > i; j--) {
161 _covered[j] = _covered[j-1];
162 _committed[j] = _committed[j-1];
163 }
164 int res = i;
165 _cur_covered_regions++;
166 _covered[res].set_start(base);
167 _covered[res].set_word_size(0);
168 jbyte* ct_start = byte_for(base);
169 uintptr_t ct_start_aligned = align_size_down((uintptr_t)ct_start, _page_size);
170 _committed[res].set_start((HeapWord*)ct_start_aligned);
171 _committed[res].set_word_size(0);
172 return res;
173 }
175 int CardTableModRefBS::find_covering_region_containing(HeapWord* addr) {
176 for (int i = 0; i < _cur_covered_regions; i++) {
177 if (_covered[i].contains(addr)) {
178 return i;
179 }
180 }
181 assert(0, "address outside of heap?");
182 return -1;
183 }
185 HeapWord* CardTableModRefBS::largest_prev_committed_end(int ind) const {
186 HeapWord* max_end = NULL;
187 for (int j = 0; j < ind; j++) {
188 HeapWord* this_end = _committed[j].end();
189 if (this_end > max_end) max_end = this_end;
190 }
191 return max_end;
192 }
194 MemRegion CardTableModRefBS::committed_unique_to_self(int self,
195 MemRegion mr) const {
196 MemRegion result = mr;
197 for (int r = 0; r < _cur_covered_regions; r += 1) {
198 if (r != self) {
199 result = result.minus(_committed[r]);
200 }
201 }
202 // Never include the guard page.
203 result = result.minus(_guard_region);
204 return result;
205 }
207 void CardTableModRefBS::resize_covered_region(MemRegion new_region) {
208 // We don't change the start of a region, only the end.
209 assert(_whole_heap.contains(new_region),
210 "attempt to cover area not in reserved area");
211 debug_only(verify_guard();)
212 // collided is true if the expansion would push into another committed region
213 debug_only(bool collided = false;)
214 int const ind = find_covering_region_by_base(new_region.start());
215 MemRegion const old_region = _covered[ind];
216 assert(old_region.start() == new_region.start(), "just checking");
217 if (new_region.word_size() != old_region.word_size()) {
218 // Commit new or uncommit old pages, if necessary.
219 MemRegion cur_committed = _committed[ind];
220 // Extend the end of this _commited region
221 // to cover the end of any lower _committed regions.
222 // This forms overlapping regions, but never interior regions.
223 HeapWord* const max_prev_end = largest_prev_committed_end(ind);
224 if (max_prev_end > cur_committed.end()) {
225 cur_committed.set_end(max_prev_end);
226 }
227 // Align the end up to a page size (starts are already aligned).
228 jbyte* const new_end = byte_after(new_region.last());
229 HeapWord* new_end_aligned =
230 (HeapWord*) align_size_up((uintptr_t)new_end, _page_size);
231 assert(new_end_aligned >= (HeapWord*) new_end,
232 "align up, but less");
233 // Check the other regions (excludes "ind") to ensure that
234 // the new_end_aligned does not intrude onto the committed
235 // space of another region.
236 int ri = 0;
237 for (ri = 0; ri < _cur_covered_regions; ri++) {
238 if (ri != ind) {
239 if (_committed[ri].contains(new_end_aligned)) {
240 // The prior check included in the assert
241 // (new_end_aligned >= _committed[ri].start())
242 // is redundant with the "contains" test.
243 // Any region containing the new end
244 // should start at or beyond the region found (ind)
245 // for the new end (committed regions are not expected to
246 // be proper subsets of other committed regions).
247 assert(_committed[ri].start() >= _committed[ind].start(),
248 "New end of committed region is inconsistent");
249 new_end_aligned = _committed[ri].start();
250 // new_end_aligned can be equal to the start of its
251 // committed region (i.e., of "ind") if a second
252 // region following "ind" also start at the same location
253 // as "ind".
254 assert(new_end_aligned >= _committed[ind].start(),
255 "New end of committed region is before start");
256 debug_only(collided = true;)
257 // Should only collide with 1 region
258 break;
259 }
260 }
261 }
262 #ifdef ASSERT
263 for (++ri; ri < _cur_covered_regions; ri++) {
264 assert(!_committed[ri].contains(new_end_aligned),
265 "New end of committed region is in a second committed region");
266 }
267 #endif
268 // The guard page is always committed and should not be committed over.
269 // "guarded" is used for assertion checking below and recalls the fact
270 // that the would-be end of the new committed region would have
271 // penetrated the guard page.
272 HeapWord* new_end_for_commit = new_end_aligned;
274 DEBUG_ONLY(bool guarded = false;)
275 if (new_end_for_commit > _guard_region.start()) {
276 new_end_for_commit = _guard_region.start();
277 DEBUG_ONLY(guarded = true;)
278 }
280 if (new_end_for_commit > cur_committed.end()) {
281 // Must commit new pages.
282 MemRegion const new_committed =
283 MemRegion(cur_committed.end(), new_end_for_commit);
285 assert(!new_committed.is_empty(), "Region should not be empty here");
286 if (!os::commit_memory((char*)new_committed.start(),
287 new_committed.byte_size(), _page_size)) {
288 // Do better than this for Merlin
289 vm_exit_out_of_memory(new_committed.byte_size(),
290 "card table expansion");
291 }
292 // Use new_end_aligned (as opposed to new_end_for_commit) because
293 // the cur_committed region may include the guard region.
294 } else if (new_end_aligned < cur_committed.end()) {
295 // Must uncommit pages.
296 MemRegion const uncommit_region =
297 committed_unique_to_self(ind, MemRegion(new_end_aligned,
298 cur_committed.end()));
299 if (!uncommit_region.is_empty()) {
300 // It is not safe to uncommit cards if the boundary between
301 // the generations is moving. A shrink can uncommit cards
302 // owned by generation A but being used by generation B.
303 if (!UseAdaptiveGCBoundary) {
304 if (!os::uncommit_memory((char*)uncommit_region.start(),
305 uncommit_region.byte_size())) {
306 assert(false, "Card table contraction failed");
307 // The call failed so don't change the end of the
308 // committed region. This is better than taking the
309 // VM down.
310 new_end_aligned = _committed[ind].end();
311 }
312 } else {
313 new_end_aligned = _committed[ind].end();
314 }
315 }
316 }
317 // In any case, we can reset the end of the current committed entry.
318 _committed[ind].set_end(new_end_aligned);
320 #ifdef ASSERT
321 // Check that the last card in the new region is committed according
322 // to the tables.
323 bool covered = false;
324 for (int cr = 0; cr < _cur_covered_regions; cr++) {
325 if (_committed[cr].contains(new_end - 1)) {
326 covered = true;
327 break;
328 }
329 }
330 assert(covered, "Card for end of new region not committed");
331 #endif
333 // The default of 0 is not necessarily clean cards.
334 jbyte* entry;
335 if (old_region.last() < _whole_heap.start()) {
336 entry = byte_for(_whole_heap.start());
337 } else {
338 entry = byte_after(old_region.last());
339 }
340 assert(index_for(new_region.last()) < _guard_index,
341 "The guard card will be overwritten");
342 // This line commented out cleans the newly expanded region and
343 // not the aligned up expanded region.
344 // jbyte* const end = byte_after(new_region.last());
345 jbyte* const end = (jbyte*) new_end_for_commit;
346 assert((end >= byte_after(new_region.last())) || collided || guarded,
347 "Expect to be beyond new region unless impacting another region");
348 // do nothing if we resized downward.
349 #ifdef ASSERT
350 for (int ri = 0; ri < _cur_covered_regions; ri++) {
351 if (ri != ind) {
352 // The end of the new committed region should not
353 // be in any existing region unless it matches
354 // the start of the next region.
355 assert(!_committed[ri].contains(end) ||
356 (_committed[ri].start() == (HeapWord*) end),
357 "Overlapping committed regions");
358 }
359 }
360 #endif
361 if (entry < end) {
362 memset(entry, clean_card, pointer_delta(end, entry, sizeof(jbyte)));
363 }
364 }
365 // In any case, the covered size changes.
366 _covered[ind].set_word_size(new_region.word_size());
367 if (TraceCardTableModRefBS) {
368 gclog_or_tty->print_cr("CardTableModRefBS::resize_covered_region: ");
369 gclog_or_tty->print_cr(" "
370 " _covered[%d].start(): " INTPTR_FORMAT
371 " _covered[%d].last(): " INTPTR_FORMAT,
372 ind, _covered[ind].start(),
373 ind, _covered[ind].last());
374 gclog_or_tty->print_cr(" "
375 " _committed[%d].start(): " INTPTR_FORMAT
376 " _committed[%d].last(): " INTPTR_FORMAT,
377 ind, _committed[ind].start(),
378 ind, _committed[ind].last());
379 gclog_or_tty->print_cr(" "
380 " byte_for(start): " INTPTR_FORMAT
381 " byte_for(last): " INTPTR_FORMAT,
382 byte_for(_covered[ind].start()),
383 byte_for(_covered[ind].last()));
384 gclog_or_tty->print_cr(" "
385 " addr_for(start): " INTPTR_FORMAT
386 " addr_for(last): " INTPTR_FORMAT,
387 addr_for((jbyte*) _committed[ind].start()),
388 addr_for((jbyte*) _committed[ind].last()));
389 }
390 // Touch the last card of the covered region to show that it
391 // is committed (or SEGV).
392 debug_only(*byte_for(_covered[ind].last());)
393 debug_only(verify_guard();)
394 }
396 // Note that these versions are precise! The scanning code has to handle the
397 // fact that the write barrier may be either precise or imprecise.
399 void CardTableModRefBS::write_ref_field_work(void* field, oop newVal) {
400 inline_write_ref_field(field, newVal);
401 }
403 /*
404 Claimed and deferred bits are used together in G1 during the evacuation
405 pause. These bits can have the following state transitions:
406 1. The claimed bit can be put over any other card state. Except that
407 the "dirty -> dirty and claimed" transition is checked for in
408 G1 code and is not used.
409 2. Deferred bit can be set only if the previous state of the card
410 was either clean or claimed. mark_card_deferred() is wait-free.
411 We do not care if the operation is be successful because if
412 it does not it will only result in duplicate entry in the update
413 buffer because of the "cache-miss". So it's not worth spinning.
414 */
417 bool CardTableModRefBS::claim_card(size_t card_index) {
418 jbyte val = _byte_map[card_index];
419 assert(val != dirty_card_val(), "Shouldn't claim a dirty card");
420 while (val == clean_card_val() ||
421 (val & (clean_card_mask_val() | claimed_card_val())) != claimed_card_val()) {
422 jbyte new_val = val;
423 if (val == clean_card_val()) {
424 new_val = (jbyte)claimed_card_val();
425 } else {
426 new_val = val | (jbyte)claimed_card_val();
427 }
428 jbyte res = Atomic::cmpxchg(new_val, &_byte_map[card_index], val);
429 if (res == val) {
430 return true;
431 }
432 val = res;
433 }
434 return false;
435 }
437 bool CardTableModRefBS::mark_card_deferred(size_t card_index) {
438 jbyte val = _byte_map[card_index];
439 // It's already processed
440 if ((val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val()) {
441 return false;
442 }
443 // Cached bit can be installed either on a clean card or on a claimed card.
444 jbyte new_val = val;
445 if (val == clean_card_val()) {
446 new_val = (jbyte)deferred_card_val();
447 } else {
448 if (val & claimed_card_val()) {
449 new_val = val | (jbyte)deferred_card_val();
450 }
451 }
452 if (new_val != val) {
453 Atomic::cmpxchg(new_val, &_byte_map[card_index], val);
454 }
455 return true;
456 }
458 void CardTableModRefBS::non_clean_card_iterate_possibly_parallel(Space* sp,
459 MemRegion mr,
460 OopsInGenClosure* cl,
461 CardTableRS* ct) {
462 if (!mr.is_empty()) {
463 int n_threads = SharedHeap::heap()->n_par_threads();
464 if (n_threads > 0) {
465 #ifndef SERIALGC
466 non_clean_card_iterate_parallel_work(sp, mr, cl, ct, n_threads);
467 #else // SERIALGC
468 fatal("Parallel gc not supported here.");
469 #endif // SERIALGC
470 } else {
471 // We do not call the non_clean_card_iterate_serial() version below because
472 // we want to clear the cards (which non_clean_card_iterate_serial() does not
473 // do for us): clear_cl here does the work of finding contiguous dirty ranges
474 // of cards to process and clear.
476 DirtyCardToOopClosure* dcto_cl = sp->new_dcto_cl(cl, precision(),
477 cl->gen_boundary());
478 ClearNoncleanCardWrapper clear_cl(dcto_cl, ct);
480 clear_cl.do_MemRegion(mr);
481 }
482 }
483 }
485 // The iterator itself is not MT-aware, but
486 // MT-aware callers and closures can use this to
487 // accomplish dirty card iteration in parallel. The
488 // iterator itself does not clear the dirty cards, or
489 // change their values in any manner.
490 void CardTableModRefBS::non_clean_card_iterate_serial(MemRegion mr,
491 MemRegionClosure* cl) {
492 for (int i = 0; i < _cur_covered_regions; i++) {
493 MemRegion mri = mr.intersection(_covered[i]);
494 if (mri.word_size() > 0) {
495 jbyte* cur_entry = byte_for(mri.last());
496 jbyte* limit = byte_for(mri.start());
497 while (cur_entry >= limit) {
498 jbyte* next_entry = cur_entry - 1;
499 if (*cur_entry != clean_card) {
500 size_t non_clean_cards = 1;
501 // Should the next card be included in this range of dirty cards.
502 while (next_entry >= limit && *next_entry != clean_card) {
503 non_clean_cards++;
504 cur_entry = next_entry;
505 next_entry--;
506 }
507 // The memory region may not be on a card boundary. So that
508 // objects beyond the end of the region are not processed, make
509 // cur_cards precise with regard to the end of the memory region.
510 MemRegion cur_cards(addr_for(cur_entry),
511 non_clean_cards * card_size_in_words);
512 MemRegion dirty_region = cur_cards.intersection(mri);
513 cl->do_MemRegion(dirty_region);
514 }
515 cur_entry = next_entry;
516 }
517 }
518 }
519 }
521 void CardTableModRefBS::dirty_MemRegion(MemRegion mr) {
522 assert((HeapWord*)align_size_down((uintptr_t)mr.start(), HeapWordSize) == mr.start(), "Unaligned start");
523 assert((HeapWord*)align_size_up ((uintptr_t)mr.end(), HeapWordSize) == mr.end(), "Unaligned end" );
524 jbyte* cur = byte_for(mr.start());
525 jbyte* last = byte_after(mr.last());
526 while (cur < last) {
527 *cur = dirty_card;
528 cur++;
529 }
530 }
532 void CardTableModRefBS::invalidate(MemRegion mr, bool whole_heap) {
533 assert((HeapWord*)align_size_down((uintptr_t)mr.start(), HeapWordSize) == mr.start(), "Unaligned start");
534 assert((HeapWord*)align_size_up ((uintptr_t)mr.end(), HeapWordSize) == mr.end(), "Unaligned end" );
535 for (int i = 0; i < _cur_covered_regions; i++) {
536 MemRegion mri = mr.intersection(_covered[i]);
537 if (!mri.is_empty()) dirty_MemRegion(mri);
538 }
539 }
541 void CardTableModRefBS::clear_MemRegion(MemRegion mr) {
542 // Be conservative: only clean cards entirely contained within the
543 // region.
544 jbyte* cur;
545 if (mr.start() == _whole_heap.start()) {
546 cur = byte_for(mr.start());
547 } else {
548 assert(mr.start() > _whole_heap.start(), "mr is not covered.");
549 cur = byte_after(mr.start() - 1);
550 }
551 jbyte* last = byte_after(mr.last());
552 memset(cur, clean_card, pointer_delta(last, cur, sizeof(jbyte)));
553 }
555 void CardTableModRefBS::clear(MemRegion mr) {
556 for (int i = 0; i < _cur_covered_regions; i++) {
557 MemRegion mri = mr.intersection(_covered[i]);
558 if (!mri.is_empty()) clear_MemRegion(mri);
559 }
560 }
562 void CardTableModRefBS::dirty(MemRegion mr) {
563 jbyte* first = byte_for(mr.start());
564 jbyte* last = byte_after(mr.last());
565 memset(first, dirty_card, last-first);
566 }
568 // Unlike several other card table methods, dirty_card_iterate()
569 // iterates over dirty cards ranges in increasing address order.
570 void CardTableModRefBS::dirty_card_iterate(MemRegion mr,
571 MemRegionClosure* cl) {
572 for (int i = 0; i < _cur_covered_regions; i++) {
573 MemRegion mri = mr.intersection(_covered[i]);
574 if (!mri.is_empty()) {
575 jbyte *cur_entry, *next_entry, *limit;
576 for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last());
577 cur_entry <= limit;
578 cur_entry = next_entry) {
579 next_entry = cur_entry + 1;
580 if (*cur_entry == dirty_card) {
581 size_t dirty_cards;
582 // Accumulate maximal dirty card range, starting at cur_entry
583 for (dirty_cards = 1;
584 next_entry <= limit && *next_entry == dirty_card;
585 dirty_cards++, next_entry++);
586 MemRegion cur_cards(addr_for(cur_entry),
587 dirty_cards*card_size_in_words);
588 cl->do_MemRegion(cur_cards);
589 }
590 }
591 }
592 }
593 }
595 MemRegion CardTableModRefBS::dirty_card_range_after_reset(MemRegion mr,
596 bool reset,
597 int reset_val) {
598 for (int i = 0; i < _cur_covered_regions; i++) {
599 MemRegion mri = mr.intersection(_covered[i]);
600 if (!mri.is_empty()) {
601 jbyte* cur_entry, *next_entry, *limit;
602 for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last());
603 cur_entry <= limit;
604 cur_entry = next_entry) {
605 next_entry = cur_entry + 1;
606 if (*cur_entry == dirty_card) {
607 size_t dirty_cards;
608 // Accumulate maximal dirty card range, starting at cur_entry
609 for (dirty_cards = 1;
610 next_entry <= limit && *next_entry == dirty_card;
611 dirty_cards++, next_entry++);
612 MemRegion cur_cards(addr_for(cur_entry),
613 dirty_cards*card_size_in_words);
614 if (reset) {
615 for (size_t i = 0; i < dirty_cards; i++) {
616 cur_entry[i] = reset_val;
617 }
618 }
619 return cur_cards;
620 }
621 }
622 }
623 }
624 return MemRegion(mr.end(), mr.end());
625 }
627 // Set all the dirty cards in the given region to "precleaned" state.
628 void CardTableModRefBS::preclean_dirty_cards(MemRegion mr) {
629 for (int i = 0; i < _cur_covered_regions; i++) {
630 MemRegion mri = mr.intersection(_covered[i]);
631 if (!mri.is_empty()) {
632 jbyte *cur_entry, *limit;
633 for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last());
634 cur_entry <= limit;
635 cur_entry++) {
636 if (*cur_entry == dirty_card) {
637 *cur_entry = precleaned_card;
638 }
639 }
640 }
641 }
642 }
644 uintx CardTableModRefBS::ct_max_alignment_constraint() {
645 return card_size * os::vm_page_size();
646 }
648 void CardTableModRefBS::verify_guard() {
649 // For product build verification
650 guarantee(_byte_map[_guard_index] == last_card,
651 "card table guard has been modified");
652 }
654 void CardTableModRefBS::verify() {
655 verify_guard();
656 }
658 #ifndef PRODUCT
659 void CardTableModRefBS::verify_region(MemRegion mr,
660 jbyte val, bool val_equals) {
661 jbyte* start = byte_for(mr.start());
662 jbyte* end = byte_for(mr.last());
663 bool failures = false;
664 for (jbyte* curr = start; curr <= end; ++curr) {
665 jbyte curr_val = *curr;
666 bool failed = (val_equals) ? (curr_val != val) : (curr_val == val);
667 if (failed) {
668 if (!failures) {
669 tty->cr();
670 tty->print_cr("== CT verification failed: ["PTR_FORMAT","PTR_FORMAT"]");
671 tty->print_cr("== %sexpecting value: %d",
672 (val_equals) ? "" : "not ", val);
673 failures = true;
674 }
675 tty->print_cr("== card "PTR_FORMAT" ["PTR_FORMAT","PTR_FORMAT"], "
676 "val: %d", curr, addr_for(curr),
677 (HeapWord*) (((size_t) addr_for(curr)) + card_size),
678 (int) curr_val);
679 }
680 }
681 guarantee(!failures, "there should not have been any failures");
682 }
684 void CardTableModRefBS::verify_not_dirty_region(MemRegion mr) {
685 verify_region(mr, dirty_card, false /* val_equals */);
686 }
688 void CardTableModRefBS::verify_dirty_region(MemRegion mr) {
689 verify_region(mr, dirty_card, true /* val_equals */);
690 }
691 #endif
693 bool CardTableModRefBSForCTRS::card_will_be_scanned(jbyte cv) {
694 return
695 CardTableModRefBS::card_will_be_scanned(cv) ||
696 _rs->is_prev_nonclean_card_val(cv);
697 };
699 bool CardTableModRefBSForCTRS::card_may_have_been_dirty(jbyte cv) {
700 return
701 cv != clean_card &&
702 (CardTableModRefBS::card_may_have_been_dirty(cv) ||
703 CardTableRS::youngergen_may_have_been_dirty(cv));
704 };